{"version":"1.0.0","segments":[{"startTime":0.15,"endTime":4.5,"body":"- Today's lecture is"},{"startTime":0.15,"endTime":4.5,"body":"very much a continuation"},{"startTime":4.5,"endTime":9.5,"body":"of the last two lectures"},{"startTime":4.5,"endTime":9.5,"body":"in my previous series."},{"startTime":9.75,"endTime":11.82,"body":"Specifically, I'm thinking of the lecture"},{"startTime":11.82,"endTime":14.34,"body":"on Planetary Universe"},{"startTime":14.34,"endTime":18.33,"body":"and also the one on Life in the Universe."},{"startTime":18.33,"endTime":20.07,"body":"And in this previous lecture,"},{"startTime":20.07,"endTime":22.89,"body":"I talk quite a bit about what it is"},{"startTime":22.89,"endTime":25.26,"body":"that makes a planet hospitable"},{"startTime":25.26,"endTime":27.513,"body":"and a really good place to live."},{"startTime":28.53,"endTime":32.79,"body":"Well, let's just remind"},{"startTime":28.53,"endTime":32.79,"body":"ourselves of the array of planets"},{"startTime":32.79,"endTime":34.83,"body":"and, indeed, one dwarf planet"},{"startTime":34.83,"endTime":36.99,"body":"that we don't really want to forget about,"},{"startTime":36.99,"endTime":39.18,"body":"we love you Pluto, honestly,"},{"startTime":39.18,"endTime":42.51,"body":"which is over here on the right-hand side."},{"startTime":42.51,"endTime":44.1,"body":"So these images are all taken"},{"startTime":44.1,"endTime":46.74,"body":"from various different NASA missions."},{"startTime":46.74,"endTime":49.44,"body":"Obviously, we have the Sun on the left,"},{"startTime":49.44,"endTime":51.87,"body":"and then Mercury, and then Venus,"},{"startTime":51.87,"endTime":55.32,"body":"which I'll be talking"},{"startTime":51.87,"endTime":55.32,"body":"about quite a bit today,"},{"startTime":55.32,"endTime":58.29,"body":"then Earth, which will not be forgotten"},{"startTime":58.29,"endTime":60.33,"body":"during the course of today,"},{"startTime":60.33,"endTime":64.35,"body":"then Mars, then Jupiter, the"},{"startTime":60.33,"endTime":64.35,"body":"prettiest of all the planets,"},{"startTime":64.35,"endTime":66.3,"body":"Saturn, Uranus,"},{"startTime":66.3,"endTime":69.69,"body":"Neptune, we're going to be"},{"startTime":66.3,"endTime":69.69,"body":"talking about a little bit,"},{"startTime":69.69,"endTime":73.05,"body":"and I'm afraid Pluto doesn't get a mention"},{"startTime":73.05,"endTime":76.08,"body":"in today's lecture at least."},{"startTime":76.08,"endTime":81.08,"body":"So Venus is often"},{"startTime":76.08,"endTime":81.08,"body":"regarded as Earth's twin."},{"startTime":81.15,"endTime":84.15,"body":"I don't think that's a"},{"startTime":81.15,"endTime":84.15,"body":"very good analogy at all"},{"startTime":84.15,"endTime":85.92,"body":"for reasons that I'll develop"},{"startTime":85.92,"endTime":88.35,"body":"during the course of the lecture."},{"startTime":88.35,"endTime":90.627,"body":"But it's certainly one of the neighbors,"},{"startTime":90.627,"endTime":93.27,"body":"and we do well to look at the neighbors"},{"startTime":93.27,"endTime":96.63,"body":"and compare and contrast their situation"},{"startTime":96.63,"endTime":100.98,"body":"to cast perspective on our own situation."},{"startTime":100.98,"endTime":103.83,"body":"So we know for sure that Venus"},{"startTime":103.83,"endTime":106.59,"body":"is closer to the Sun than we are"},{"startTime":106.59,"endTime":108.39,"body":"because, just occasionally,"},{"startTime":108.39,"endTime":112.29,"body":"we see it to transit in front of the Sun,"},{"startTime":112.29,"endTime":117.29,"body":"so we know that it lies"},{"startTime":112.29,"endTime":117.29,"body":"between the Sun and ourselves."},{"startTime":117.51,"endTime":119.31,"body":"This is only a rare event,"},{"startTime":119.31,"endTime":122.01,"body":"and it's not going to"},{"startTime":119.31,"endTime":122.01,"body":"happen again in the lifetime"},{"startTime":122.01,"endTime":125.583,"body":"of any of us sitting in this"},{"startTime":122.01,"endTime":125.583,"body":"lecture theater tonight."},{"startTime":126.69,"endTime":129.21,"body":"But let's go further away to start with,"},{"startTime":129.21,"endTime":132.06,"body":"and let's think about Neptune."},{"startTime":132.06,"endTime":137.06,"body":"Neptune is the furthest"},{"startTime":132.06,"endTime":137.06,"body":"planet from our Sun,"},{"startTime":137.07,"endTime":139.59,"body":"and, as such, it's very cold,"},{"startTime":139.59,"endTime":141.36,"body":"but that's not the only thing about it"},{"startTime":141.36,"endTime":143.973,"body":"that's different from planet Earth."},{"startTime":144.84,"endTime":149.16,"body":"The spin, rotation on Neptune"},{"startTime":149.16,"endTime":152.64,"body":"is a tad faster than on Earth."},{"startTime":152.64,"endTime":155.13,"body":"One day takes about 16 hours."},{"startTime":155.13,"endTime":158.88,"body":"So, if you think we're racing"},{"startTime":155.13,"endTime":158.88,"body":"through the days in September,"},{"startTime":158.88,"endTime":161.07,"body":"and here I very much agree with you,"},{"startTime":161.07,"endTime":163.59,"body":"then you'd find that you"},{"startTime":161.07,"endTime":163.59,"body":"rattle through the days"},{"startTime":163.59,"endTime":166.173,"body":"rather more quickly on Neptune."},{"startTime":167.04,"endTime":169.62,"body":"Neptune's axis of rotation"},{"startTime":169.62,"endTime":173.73,"body":"about which it's doing that"},{"startTime":169.62,"endTime":173.73,"body":"spinning every 16 hours"},{"startTime":173.73,"endTime":177.09,"body":"is about 28 degrees,"},{"startTime":177.09,"endTime":181.17,"body":"with respect to the plane"},{"startTime":177.09,"endTime":181.17,"body":"of its orbit around the Sun."},{"startTime":181.17,"endTime":183.27,"body":"And so that's fairly similar"},{"startTime":183.27,"endTime":187.29,"body":"to the axial tilt here on Earth,"},{"startTime":187.29,"endTime":191.37,"body":"which means that Neptune"},{"startTime":187.29,"endTime":191.37,"body":"experiences seasons"},{"startTime":191.37,"endTime":193.803,"body":"just like we do here on Earth."},{"startTime":194.76,"endTime":199.76,"body":"However, because the year"},{"startTime":194.76,"endTime":199.76,"body":"on Neptune is so long,"},{"startTime":199.86,"endTime":201.78,"body":"then each of the seasons,"},{"startTime":201.78,"endTime":204.84,"body":"each of the four seasons on Neptune,"},{"startTime":204.84,"endTime":207.87,"body":"lasts for over 40 years."},{"startTime":207.87,"endTime":211.23,"body":"That will seem rather longer"},{"startTime":207.87,"endTime":211.23,"body":"than the three months of summer"},{"startTime":211.23,"endTime":213.36,"body":"that we just went through."},{"startTime":213.36,"endTime":216.33,"body":"And that's because a year on Neptune"},{"startTime":216.33,"endTime":220.68,"body":"lasts about 165 Earth years."},{"startTime":220.68,"endTime":223.65,"body":"So Neptune would be very different indeed."},{"startTime":223.65,"endTime":227.52,"body":"It is way outside the habitable zone."},{"startTime":227.52,"endTime":229.86,"body":"It is just too cold,"},{"startTime":229.86,"endTime":234.06,"body":"too far to receive enough"},{"startTime":229.86,"endTime":234.06,"body":"heat energy from the Sun"},{"startTime":234.06,"endTime":237.873,"body":"to be warm enough for"},{"startTime":234.06,"endTime":237.873,"body":"creatures like us to inhabit."},{"startTime":238.98,"endTime":241.02,"body":"Although that may sound a tad gloomy,"},{"startTime":241.02,"endTime":244.62,"body":"I hope I can cheer you up"},{"startTime":241.02,"endTime":244.62,"body":"with some very new images"},{"startTime":244.62,"endTime":249.09,"body":"taken by NASA's newest"},{"startTime":244.62,"endTime":249.09,"body":"space telescope, the JWST."},{"startTime":250.5,"endTime":252.06,"body":"I don't know if you've already seen"},{"startTime":252.06,"endTime":254.13,"body":"this really beautiful image"},{"startTime":254.13,"endTime":256.89,"body":"taken in the direction of Neptune."},{"startTime":256.89,"endTime":258.783,"body":"It was taken back in July."},{"startTime":259.95,"endTime":261.33,"body":"I thought it was breathtaking."},{"startTime":261.33,"endTime":263.61,"body":"I still think it's breathtaking."},{"startTime":263.61,"endTime":266.76,"body":"I love the fact that even though Neptune"},{"startTime":266.76,"endTime":270.63,"body":"is really quite large compared with Earth,"},{"startTime":270.63,"endTime":274.14,"body":"if the Earth were the size of a walnut,"},{"startTime":274.14,"endTime":276.39,"body":"then Neptune would be"},{"startTime":274.14,"endTime":276.39,"body":"as big as a football."},{"startTime":276.39,"endTime":278.13,"body":"That's the kind of difference in scale"},{"startTime":278.13,"endTime":279.69,"body":"that we're talking about."},{"startTime":279.69,"endTime":281.76,"body":"But in this particular image,"},{"startTime":281.76,"endTime":285.18,"body":"we see Neptune against"},{"startTime":281.76,"endTime":285.18,"body":"a wide field of view,"},{"startTime":285.18,"endTime":289.41,"body":"and down there, there's a"},{"startTime":285.18,"endTime":289.41,"body":"really beautiful spiral galaxy."},{"startTime":289.41,"endTime":292.62,"body":"It's well worth downloading"},{"startTime":289.41,"endTime":292.62,"body":"this image from the NASA website"},{"startTime":292.62,"endTime":294.72,"body":"just to admire the many galaxies"},{"startTime":294.72,"endTime":297.123,"body":"in this beautiful wide-field view."},{"startTime":298.32,"endTime":301.77,"body":"This image was taken by"},{"startTime":298.32,"endTime":301.77,"body":"what's called NIRCam,"},{"startTime":301.77,"endTime":304.02,"body":"the Near Infrared Camera."},{"startTime":304.02,"endTime":308.1,"body":"So that's the portion of"},{"startTime":304.02,"endTime":308.1,"body":"the infrared energy band"},{"startTime":308.1,"endTime":309.51,"body":"between the optical"},{"startTime":309.51,"endTime":314.51,"body":"and the full-on, serious,"},{"startTime":309.51,"endTime":314.51,"body":"thermal infrared wave band."},{"startTime":314.82,"endTime":317.973,"body":"It's just an absolutely spectacular image."},{"startTime":318.93,"endTime":322.83,"body":"So Neptune is dark, because"},{"startTime":318.93,"endTime":322.83,"body":"it's so far away from the Sun,"},{"startTime":322.83,"endTime":324.99,"body":"and it is cold."},{"startTime":324.99,"endTime":329.04,"body":"It is 30 times more distant from the Sun"},{"startTime":329.04,"endTime":331.293,"body":"than planet Earth is."},{"startTime":332.22,"endTime":335.46,"body":"Neptune is the only"},{"startTime":332.22,"endTime":335.46,"body":"planet in our solar system"},{"startTime":335.46,"endTime":339.54,"body":"not to be visible at all to the naked eye."},{"startTime":339.54,"endTime":342.84,"body":"Interestingly, Neptune"},{"startTime":339.54,"endTime":342.84,"body":"was the very first planet"},{"startTime":342.84,"endTime":346.05,"body":"to be predicted on the"},{"startTime":342.84,"endTime":346.05,"body":"basis of mathematics."},{"startTime":346.05,"endTime":349.05,"body":"Because of deductions about the behavior"},{"startTime":349.05,"endTime":351.78,"body":"of orbits nearby to Neptune,"},{"startTime":351.78,"endTime":354.54,"body":"it became clear that"},{"startTime":351.78,"endTime":354.54,"body":"something else was going on."},{"startTime":354.54,"endTime":357.15,"body":"Hence, its discovery."},{"startTime":357.15,"endTime":360.63,"body":"It was discovered in 1846."},{"startTime":360.63,"endTime":363.69,"body":"And it was only 11 years ago"},{"startTime":363.69,"endTime":368.22,"body":"that Neptune completed an"},{"startTime":363.69,"endTime":368.22,"body":"entire year, a Neptune year,"},{"startTime":368.22,"endTime":372.033,"body":"since someone on Earth had discovered it."},{"startTime":373.41,"endTime":378.36,"body":"Not only is it too dark and"},{"startTime":373.41,"endTime":378.36,"body":"too cold for life to survive,"},{"startTime":378.36,"endTime":382.86,"body":"but the atmosphere just"},{"startTime":378.36,"endTime":382.86,"body":"doesn't work for human lungs."},{"startTime":382.86,"endTime":386.88,"body":"It's largely composed"},{"startTime":382.86,"endTime":386.88,"body":"of hydrogen and helium,"},{"startTime":386.88,"endTime":389.703,"body":"very light elements indeed."},{"startTime":390.6,"endTime":393.51,"body":"The weather is pretty dreadful as well."},{"startTime":393.51,"endTime":395.193,"body":"Winds whip around."},{"startTime":396.84,"endTime":401.01,"body":"There's also quite a bit of"},{"startTime":396.84,"endTime":401.01,"body":"methane in Neptune's atmosphere,"},{"startTime":401.01,"endTime":404.82,"body":"and some of the winds in"},{"startTime":401.01,"endTime":404.82,"body":"the top of the atmosphere"},{"startTime":404.82,"endTime":406.41,"body":"move across the planet"},{"startTime":406.41,"endTime":410.97,"body":"at speeds of about 2,000"},{"startTime":406.41,"endTime":410.97,"body":"kilometers per hour."},{"startTime":410.97,"endTime":412.86,"body":"That's about 1,200 miles per hour."},{"startTime":412.86,"endTime":414.81,"body":"Whichever units you prefer,"},{"startTime":414.81,"endTime":418.83,"body":"it's still really fast"},{"startTime":414.81,"endTime":418.83,"body":"and really inhospitable."},{"startTime":418.83,"endTime":421.323,"body":"It is utterly hostile to life,"},{"startTime":422.19,"endTime":424.47,"body":"yet it is a thing of beauty."},{"startTime":424.47,"endTime":427.923,"body":"So here is just a zoom in of Neptune."},{"startTime":428.79,"endTime":430.95,"body":"And this new image from the JWST"},{"startTime":430.95,"endTime":434.82,"body":"showing in very sharp"},{"startTime":430.95,"endTime":434.82,"body":"detail the beautiful rings"},{"startTime":434.82,"endTime":437.1,"body":"which were discovered by"},{"startTime":434.82,"endTime":437.1,"body":"a previous NASA mission,"},{"startTime":437.1,"endTime":438.153,"body":"Mariner 2,"},{"startTime":440.97,"endTime":443.88,"body":"in the late 1980s."},{"startTime":443.88,"endTime":447.51,"body":"Here are some of the moons around Neptune,"},{"startTime":447.51,"endTime":450.48,"body":"with Triton showing just up there,"},{"startTime":450.48,"endTime":453.303,"body":"and here is a beautiful zoom in."},{"startTime":454.23,"endTime":459.15,"body":"It's a little saturated"},{"startTime":454.23,"endTime":459.15,"body":"out on the screen here,"},{"startTime":459.15,"endTime":461.58,"body":"but, in fact, there"},{"startTime":459.15,"endTime":461.58,"body":"are some bright patches"},{"startTime":461.58,"endTime":464.61,"body":"in the southern hemisphere of Neptune,"},{"startTime":464.61,"endTime":467.73,"body":"that's in the bottom"},{"startTime":464.61,"endTime":467.73,"body":"half of the main disc,"},{"startTime":467.73,"endTime":472.73,"body":"and these correspond to"},{"startTime":467.73,"endTime":472.73,"body":"high-altitude methane ice clouds."},{"startTime":476.4,"endTime":481.11,"body":"For the first time, the"},{"startTime":476.4,"endTime":481.11,"body":"JWST was able to image"},{"startTime":481.11,"endTime":486.11,"body":"some of the meteorological"},{"startTime":481.11,"endTime":486.11,"body":"conditions on Neptune,"},{"startTime":486.18,"endTime":490.98,"body":"and so it's extremely helpful"},{"startTime":486.18,"endTime":490.98,"body":"for atmospheric physicists"},{"startTime":490.98,"endTime":493.71,"body":"to be able to study the atmosphere"},{"startTime":493.71,"endTime":496.713,"body":"of planet Neptune in this detail."},{"startTime":497.7,"endTime":501.63,"body":"So this is the kind of"},{"startTime":497.7,"endTime":501.63,"body":"amazing image that you can get"},{"startTime":501.63,"endTime":505.53,"body":"from a $10 billion space telescope."},{"startTime":505.53,"endTime":508.02,"body":"I'm now going to show you"},{"startTime":505.53,"endTime":508.02,"body":"an image taken with my phone"},{"startTime":508.02,"endTime":511.41,"body":"outside of my kitchen door during lockdown"},{"startTime":511.41,"endTime":513.99,"body":"of another planet in the solar system."},{"startTime":513.99,"endTime":515.85,"body":"That's Venus right at the top"},{"startTime":515.85,"endTime":518.25,"body":"and our moon right at the bottom."},{"startTime":518.25,"endTime":521.16,"body":"This is literally handheld with my phone"},{"startTime":521.16,"endTime":523.98,"body":"outside of our kitchen door."},{"startTime":523.98,"endTime":526.65,"body":"The clarity of the sky was something"},{"startTime":526.65,"endTime":530.34,"body":"that seemed to characterize"},{"startTime":526.65,"endTime":530.34,"body":"the first few weeks"},{"startTime":530.34,"endTime":531.93,"body":"of that first lockdown,"},{"startTime":531.93,"endTime":535.8,"body":"which is when I took this photograph."},{"startTime":535.8,"endTime":540.8,"body":"Venus is often known as the"},{"startTime":535.8,"endTime":540.8,"body":"Evening Star or the Morning Star"},{"startTime":540.9,"endTime":543.15,"body":"because of that business"},{"startTime":540.9,"endTime":543.15,"body":"I talked about earlier,"},{"startTime":543.15,"endTime":545.28,"body":"that it's really close in."},{"startTime":545.28,"endTime":549.36,"body":"It's on a really relatively"},{"startTime":545.28,"endTime":549.36,"body":"smaller orbit closer to the Sun,"},{"startTime":549.36,"endTime":551.64,"body":"so it's never very far from the Sun."},{"startTime":551.64,"endTime":555.03,"body":"So, when the Sun is setting,"},{"startTime":551.64,"endTime":555.03,"body":"it's not far behind."},{"startTime":555.03,"endTime":558.33,"body":"When the Sun is rising,"},{"startTime":555.03,"endTime":558.33,"body":"it's not far behind."},{"startTime":558.33,"endTime":562.56,"body":"Whether we see it as the"},{"startTime":558.33,"endTime":562.56,"body":"Morning Star or the Evening Star"},{"startTime":562.56,"endTime":567.56,"body":"depends very much on what part"},{"startTime":562.56,"endTime":567.56,"body":"of the Venus year we are in."},{"startTime":569.16,"endTime":572.16,"body":"Venus is shrouded in cloud."},{"startTime":572.16,"endTime":575.1,"body":"We can't see all the way to the surface"},{"startTime":575.1,"endTime":578.34,"body":"because of all the"},{"startTime":575.1,"endTime":578.34,"body":"clouds in its atmosphere."},{"startTime":578.34,"endTime":581.22,"body":"More of those a little later on."},{"startTime":581.22,"endTime":585.03,"body":"But Venus appears so"},{"startTime":581.22,"endTime":585.03,"body":"bright in the night sky"},{"startTime":585.03,"endTime":589.787,"body":"because those clouds have what"},{"startTime":585.03,"endTime":589.787,"body":"we call a very high albedo."},{"startTime":590.97,"endTime":593.43,"body":"What do I mean by albedo?"},{"startTime":593.43,"endTime":598.43,"body":"The albedo measures how"},{"startTime":593.43,"endTime":598.43,"body":"reflective a surface is."},{"startTime":598.56,"endTime":602.13,"body":"So snow and ice and white clouds,"},{"startTime":602.13,"endTime":604.38,"body":"they have a very high albedo."},{"startTime":604.38,"endTime":606.99,"body":"They reflect a lot of sunlight,"},{"startTime":606.99,"endTime":610.62,"body":"so we see the object"},{"startTime":606.99,"endTime":610.62,"body":"that's doing the reflecting"},{"startTime":610.62,"endTime":611.82,"body":"to be very bright,"},{"startTime":611.82,"endTime":614.88,"body":"which is why you can take"},{"startTime":611.82,"endTime":614.88,"body":"a photograph of Venus"},{"startTime":614.88,"endTime":616.263,"body":"even with a phone."},{"startTime":617.46,"endTime":621.63,"body":"So snow and ice have a high"},{"startTime":617.46,"endTime":621.63,"body":"albedo, sunlight is reflected,"},{"startTime":621.63,"endTime":624.69,"body":"and, in fact, that then cools the ice"},{"startTime":624.69,"endTime":627.66,"body":"and the snow underneath a bit more"},{"startTime":627.66,"endTime":631.83,"body":"because it's reflected"},{"startTime":627.66,"endTime":631.83,"body":"the heat energy away."},{"startTime":631.83,"endTime":636.83,"body":"In contrast, seawater is"},{"startTime":631.83,"endTime":636.83,"body":"not as reflective as ice"},{"startTime":637.26,"endTime":640.68,"body":"and, therefore, it absorbs"},{"startTime":637.26,"endTime":640.68,"body":"more heat from the Sun"},{"startTime":640.68,"endTime":642.81,"body":"because it doesn't reflect as much,"},{"startTime":642.81,"endTime":644.913,"body":"and, therefore, it gets hotter."},{"startTime":645.87,"endTime":649.56,"body":"In Venus, it's those"},{"startTime":645.87,"endTime":649.56,"body":"clouds that are responsible"},{"startTime":649.56,"endTime":653.403,"body":"for its high albedo,"},{"startTime":649.56,"endTime":653.403,"body":"its high reflectivity,"},{"startTime":654.54,"endTime":656.37,"body":"and that's why we can see it"},{"startTime":656.37,"endTime":660.57,"body":"to be so very bright in this image."},{"startTime":660.57,"endTime":664.65,"body":"The albedo of Venus is something like 0.7."},{"startTime":664.65,"endTime":668.07,"body":"Albedo is measured between zero and one."},{"startTime":668.07,"endTime":672.03,"body":"Black velvet would have an"},{"startTime":668.07,"endTime":672.03,"body":"albedo very close to zero,"},{"startTime":672.03,"endTime":674.25,"body":"but perfect ice would have,"},{"startTime":674.25,"endTime":677.01,"body":"perfect snow or a perfect mirror"},{"startTime":677.01,"endTime":679.38,"body":"would have an albedo close to one."},{"startTime":679.38,"endTime":683.16,"body":"The albedo of Venus is about 0.7,"},{"startTime":683.16,"endTime":687.27,"body":"so that means it reflects 70% of the light"},{"startTime":687.27,"endTime":689.493,"body":"from the Sun that strikes it."},{"startTime":691.02,"endTime":695.49,"body":"When the Moon is close to being"},{"startTime":691.02,"endTime":695.49,"body":"a full moon in Earth's sky,"},{"startTime":695.49,"endTime":698.61,"body":"it can look a lot brighter than Venus,"},{"startTime":698.61,"endTime":703.2,"body":"even though the Moon's"},{"startTime":698.61,"endTime":703.2,"body":"albedo is only about 0.1."},{"startTime":703.2,"endTime":707.04,"body":"The Moon is basically a lump"},{"startTime":703.2,"endTime":707.04,"body":"of coal, a sphere of coal,"},{"startTime":707.04,"endTime":708.75,"body":"but with really good PR."},{"startTime":708.75,"endTime":710.7,"body":"But because it's much closer to us,"},{"startTime":710.7,"endTime":713.403,"body":"it appears to be much, much brighter."},{"startTime":714.36,"endTime":716.73,"body":"So Venus looks really quite tranquil"},{"startTime":716.73,"endTime":719.82,"body":"and really quite beautiful, doesn't it?"},{"startTime":719.82,"endTime":722.43,"body":"Let's just learn a little more about Venus"},{"startTime":722.43,"endTime":725.97,"body":"and see if we can understand"},{"startTime":722.43,"endTime":725.97,"body":"what's different about Venus"},{"startTime":725.97,"endTime":728.493,"body":"compared with planet Earth."},{"startTime":729.33,"endTime":730.86,"body":"One thing to note first of all"},{"startTime":730.86,"endTime":733.8,"body":"is that Venus takes a"},{"startTime":730.86,"endTime":733.8,"body":"really long time to spin,"},{"startTime":733.8,"endTime":736.41,"body":"a really long time to rotate."},{"startTime":736.41,"endTime":740.73,"body":"So one day on Venus takes,"},{"startTime":740.73,"endTime":742.59,"body":"forget the 16 hours of Neptune,"},{"startTime":742.59,"endTime":747.59,"body":"one day on Venus takes 243 Earth days."},{"startTime":749.19,"endTime":750.84,"body":"The other interesting thing about Venus"},{"startTime":750.84,"endTime":755.43,"body":"is it rotates in the opposite"},{"startTime":750.84,"endTime":755.43,"body":"direction compared with Earth."},{"startTime":755.43,"endTime":759.27,"body":"So, on Venus, the Sun rises in the west"},{"startTime":759.27,"endTime":762.78,"body":"and it sets in the east,"},{"startTime":759.27,"endTime":762.78,"body":"the opposite to Earth"},{"startTime":762.78,"endTime":765.48,"body":"and, indeed, opposite"},{"startTime":762.78,"endTime":765.48,"body":"to all the other planets"},{"startTime":765.48,"endTime":766.713,"body":"in the solar system."},{"startTime":767.85,"endTime":771.06,"body":"But because the day on Venus is so long,"},{"startTime":771.06,"endTime":776.06,"body":"the Sun rises really slowly"},{"startTime":771.06,"endTime":776.06,"body":"and it sets really slowly."},{"startTime":777.63,"endTime":779.61,"body":"The Venus year,"},{"startTime":779.61,"endTime":781.65,"body":"in other words, the time taken for Venus"},{"startTime":781.65,"endTime":784.83,"body":"to do a complete orbit around the Sun,"},{"startTime":784.83,"endTime":788.97,"body":"is 225 Earth days."},{"startTime":788.97,"endTime":793.97,"body":"So a day on Venus lasts"},{"startTime":788.97,"endTime":793.97,"body":"longer than a year on Venus."},{"startTime":795.39,"endTime":796.223,"body":"So I put it to you,"},{"startTime":796.223,"endTime":799.2,"body":"it's a really good thing that"},{"startTime":796.223,"endTime":799.2,"body":"there is no life on Venus"},{"startTime":799.2,"endTime":802.06,"body":"because birthdays would"},{"startTime":799.2,"endTime":802.06,"body":"be so very confusing"},{"startTime":803.28,"endTime":804.933,"body":"and poorly defined."},{"startTime":806.19,"endTime":809.88,"body":"But why doesn't life exist on Venus?"},{"startTime":809.88,"endTime":813.903,"body":"And why is Venus said"},{"startTime":809.88,"endTime":813.903,"body":"to be hostile to life?"},{"startTime":815.13,"endTime":817.5,"body":"Well, it's the atmosphere."},{"startTime":817.5,"endTime":821.88,"body":"The atmosphere on Venus is mostly CO2."},{"startTime":821.88,"endTime":824.73,"body":"It's mostly carbon dioxide."},{"startTime":824.73,"endTime":829.73,"body":"Here on Earth we have"},{"startTime":824.73,"endTime":829.73,"body":"approximately 80% of our atmosphere"},{"startTime":830.1,"endTime":835.1,"body":"is nitrogen, N2, which is"},{"startTime":830.1,"endTime":835.1,"body":"a very neutral sort of gas,"},{"startTime":835.71,"endTime":839.22,"body":"and then 20% approximately,"},{"startTime":835.71,"endTime":839.22,"body":"I'm rounding this up,"},{"startTime":839.22,"endTime":843.45,"body":"is oxygen, O2, and that's"},{"startTime":839.22,"endTime":843.45,"body":"what human lungs need"},{"startTime":843.45,"endTime":846.453,"body":"in order to breathe."},{"startTime":847.59,"endTime":852.59,"body":"But the atmosphere on Venus"},{"startTime":847.59,"endTime":852.59,"body":"is about 96% carbon dioxide."},{"startTime":854.64,"endTime":856.86,"body":"Is this unusual in planets?"},{"startTime":856.86,"endTime":859.47,"body":"Well, let's ask that question."},{"startTime":859.47,"endTime":862.41,"body":"What's the best way of finding out"},{"startTime":862.41,"endTime":866.31,"body":"what the constituents"},{"startTime":862.41,"endTime":866.31,"body":"of other planets are?"},{"startTime":866.31,"endTime":867.39,"body":"Well, when you've discovered them,"},{"startTime":867.39,"endTime":870.63,"body":"and I described in my"},{"startTime":867.39,"endTime":870.63,"body":"last but one lecture,"},{"startTime":870.63,"endTime":872.583,"body":"the one on planetary universes."},{"startTime":873.57,"endTime":875.01,"body":"At the end of that lecture,"},{"startTime":875.01,"endTime":878.46,"body":"I said that 5,035 planets"},{"startTime":878.46,"endTime":881.46,"body":"outside of our solar"},{"startTime":878.46,"endTime":881.46,"body":"system had been discovered,"},{"startTime":881.46,"endTime":882.75,"body":"but that's now been updated."},{"startTime":882.75,"endTime":887.43,"body":"We now know about 5,157 exoplanets,"},{"startTime":887.43,"endTime":891.3,"body":"planets outside of our solar system."},{"startTime":891.3,"endTime":892.38,"body":"Many of these planets,"},{"startTime":892.38,"endTime":895.08,"body":"including the one that"},{"startTime":892.38,"endTime":895.08,"body":"I'm about to talk about,"},{"startTime":895.08,"endTime":899.25,"body":"were discovered by a"},{"startTime":895.08,"endTime":899.25,"body":"project called SuperWASP."},{"startTime":899.25,"endTime":902.85,"body":"WASP stands for the Wide"},{"startTime":899.25,"endTime":902.85,"body":"Angle Search for Planets."},{"startTime":902.85,"endTime":904.44,"body":"And I was able to visit this"},{"startTime":904.44,"endTime":907.14,"body":"in South Africa a few years ago."},{"startTime":907.14,"endTime":911.37,"body":"It's a very simple project"},{"startTime":907.14,"endTime":911.37,"body":"but brilliantly executed."},{"startTime":911.37,"endTime":914.1,"body":"It comprises a bunch of cameras"},{"startTime":914.1,"endTime":916.38,"body":"and a bunch of expensive Canon lenses,"},{"startTime":916.38,"endTime":919.08,"body":"or expensive by the"},{"startTime":916.38,"endTime":919.08,"body":"standards of photographers,"},{"startTime":919.08,"endTime":922.98,"body":"but it's a relatively cheap"},{"startTime":919.08,"endTime":922.98,"body":"way of building a telescope"},{"startTime":922.98,"endTime":927.153,"body":"to have a set of Canon lenses"},{"startTime":922.98,"endTime":927.153,"body":"operating there together."},{"startTime":928.2,"endTime":930.66,"body":"And this is one of a number of projects"},{"startTime":930.66,"endTime":932.85,"body":"that's been responsible for the discovery"},{"startTime":932.85,"endTime":936.48,"body":"of that 5,157 planets."},{"startTime":936.48,"endTime":940.563,"body":"One of them in particular"},{"startTime":936.48,"endTime":940.563,"body":"is known as WASP-39b,"},{"startTime":941.46,"endTime":944.01,"body":"and that's a planet that was discovered"},{"startTime":944.01,"endTime":945.723,"body":"just over 10 years ago,"},{"startTime":946.71,"endTime":950.04,"body":"which people had been looking"},{"startTime":946.71,"endTime":950.04,"body":"at to try and identify"},{"startTime":950.04,"endTime":954.84,"body":"what the constituents of"},{"startTime":950.04,"endTime":954.84,"body":"its atmosphere might be."},{"startTime":954.84,"endTime":957.99,"body":"So there was a space telescope"},{"startTime":954.84,"endTime":957.99,"body":"put up some years ago,"},{"startTime":957.99,"endTime":959.46,"body":"again, by NASA."},{"startTime":959.46,"endTime":963.06,"body":"This particular space"},{"startTime":959.46,"endTime":963.06,"body":"telescope is called Spitzer"},{"startTime":963.06,"endTime":964.92,"body":"after Lyman Spitzer."},{"startTime":964.92,"endTime":968.67,"body":"And this is an infrared space telescope,"},{"startTime":968.67,"endTime":971.61,"body":"and it was a very, very"},{"startTime":968.67,"endTime":971.61,"body":"successful mission."},{"startTime":971.61,"endTime":973.9,"body":"And it can take spectra"},{"startTime":974.91,"endTime":977.04,"body":"a bit like the ones that I described"},{"startTime":977.04,"endTime":980.31,"body":"in my lecture a couple of years ago now"},{"speaker":"on Cosmic Vision","startTime":980.31,"endTime":984.21,"body":"Unravelling Rainbows,"},{"speaker":"on Cosmic Vision","startTime":984.21,"endTime":987.63,"body":"where I talked about"},{"speaker":"on Cosmic Vision","startTime":984.21,"endTime":987.63,"body":"spectroscopy and spectra"},{"speaker":"on Cosmic Vision","startTime":987.63,"endTime":992.63,"body":"as being rainbows,"},{"speaker":"on Cosmic Vision","startTime":987.63,"endTime":992.63,"body":"split-up light from stars."},{"speaker":"on Cosmic Vision","startTime":992.94,"endTime":997.83,"body":"And this Spitzer satellite"},{"speaker":"on Cosmic Vision","startTime":992.94,"endTime":997.83,"body":"can sort of take spectra"},{"speaker":"on Cosmic Vision","startTime":997.83,"endTime":1001.643,"body":"a bit like the rainbows that"},{"speaker":"on Cosmic Vision","startTime":997.83,"endTime":1001.643,"body":"I described in that lecture."},{"speaker":"on Cosmic Vision","startTime":1002.48,"endTime":1004.52,"body":"By a rainbow or a spectrum,"},{"speaker":"on Cosmic Vision","startTime":1004.52,"endTime":1008.33,"body":"I mean that, as a function"},{"speaker":"on Cosmic Vision","startTime":1004.52,"endTime":1008.33,"body":"of color or wavelength,"},{"speaker":"on Cosmic Vision","startTime":1008.33,"endTime":1011.09,"body":"we've got differences in intensity"},{"speaker":"on Cosmic Vision","startTime":1011.09,"endTime":1014.06,"body":"that tell us about different constituents"},{"speaker":"on Cosmic Vision","startTime":1014.06,"endTime":1017.21,"body":"in the atmosphere of whatever"},{"speaker":"on Cosmic Vision","startTime":1014.06,"endTime":1017.21,"body":"planet we're looking at"},{"speaker":"on Cosmic Vision","startTime":1017.21,"endTime":1019.43,"body":"or the star that we're looking at."},{"speaker":"on Cosmic Vision","startTime":1019.43,"endTime":1020.99,"body":"So, don't judge."},{"speaker":"on Cosmic Vision","startTime":1020.99,"endTime":1023.75,"body":"This is not a great spectrum"},{"speaker":"on Cosmic Vision","startTime":1020.99,"endTime":1023.75,"body":"that I'm showing you here,"},{"speaker":"on Cosmic Vision","startTime":1023.75,"endTime":1026.21,"body":"but you can see at different wavelengths"},{"speaker":"on Cosmic Vision","startTime":1026.21,"endTime":1027.83,"body":"in the infrared band,"},{"speaker":"on Cosmic Vision","startTime":1027.83,"endTime":1030.38,"body":"there's some evidence"},{"speaker":"on Cosmic Vision","startTime":1027.83,"endTime":1030.38,"body":"from the Spitzer satellite"},{"speaker":"on Cosmic Vision","startTime":1030.38,"endTime":1032.52,"body":"for slight differences"},{"speaker":"on Cosmic Vision","startTime":1034.373,"endTime":1038.543,"body":"as a function of wavelength"},{"speaker":"on Cosmic Vision","startTime":1034.373,"endTime":1038.543,"body":"or as a function of color."},{"speaker":"on Cosmic Vision","startTime":1039.41,"endTime":1041.78,"body":"So, on the basis of these hints,"},{"speaker":"on Cosmic Vision","startTime":1041.78,"endTime":1045.05,"body":"WASP-39b was then a really good target"},{"speaker":"on Cosmic Vision","startTime":1045.05,"endTime":1048.92,"body":"to look at with the wonderful JWST,"},{"speaker":"on Cosmic Vision","startTime":1048.92,"endTime":1051.35,"body":"which I'm sure many of you remember."},{"speaker":"on Cosmic Vision","startTime":1051.35,"endTime":1054.56,"body":"We had the exciting launch"},{"speaker":"on Cosmic Vision","startTime":1051.35,"endTime":1054.56,"body":"of this on Christmas morning,"},{"speaker":"on Cosmic Vision","startTime":1054.56,"endTime":1058.58,"body":"late on Christmas morning"},{"speaker":"on Cosmic Vision","startTime":1054.56,"endTime":1058.58,"body":"in the Christmas just gone."},{"speaker":"on Cosmic Vision","startTime":1058.58,"endTime":1061.193,"body":"It was just before"},{"speaker":"on Cosmic Vision","startTime":1058.58,"endTime":1061.193,"body":"lunchtime here in Europe."},{"speaker":"on Cosmic Vision","startTime":1062.06,"endTime":1065.81,"body":"This was the triumphant"},{"speaker":"on Cosmic Vision","startTime":1062.06,"endTime":1065.81,"body":"success of a lot of hard work"},{"speaker":"on Cosmic Vision","startTime":1065.81,"endTime":1070.46,"body":"by engineers and"},{"speaker":"on Cosmic Vision","startTime":1065.81,"endTime":1070.46,"body":"scientists in NASA, in ESA,"},{"speaker":"on Cosmic Vision","startTime":1070.46,"endTime":1074.09,"body":"and in the CSA, the Canadian Space Agency"},{"speaker":"on Cosmic Vision","startTime":1074.09,"endTime":1076.19,"body":"and the European Space Agency"},{"speaker":"on Cosmic Vision","startTime":1076.19,"endTime":1081.023,"body":"as well as the North American"},{"speaker":"on Cosmic Vision","startTime":1076.19,"endTime":1081.023,"body":"Space Agency, irrespectively."},{"speaker":"on Cosmic Vision","startTime":1081.86,"endTime":1086.66,"body":"It was launched from an Ariane 5 rocket"},{"speaker":"on Cosmic Vision","startTime":1086.66,"endTime":1090.29,"body":"from the Guiana Space"},{"speaker":"on Cosmic Vision","startTime":1086.66,"endTime":1090.29,"body":"Centre in South America,"},{"speaker":"on Cosmic Vision","startTime":1090.29,"endTime":1093.47,"body":"and it was a fantastically"},{"speaker":"on Cosmic Vision","startTime":1090.29,"endTime":1093.47,"body":"successful launch,"},{"speaker":"on Cosmic Vision","startTime":1093.47,"endTime":1094.61,"body":"and the deployment,"},{"speaker":"on Cosmic Vision","startTime":1094.61,"endTime":1097.61,"body":"the commissioning and the"},{"speaker":"on Cosmic Vision","startTime":1094.61,"endTime":1097.61,"body":"deployment of that telescope"},{"speaker":"on Cosmic Vision","startTime":1097.61,"endTime":1101.63,"body":"has been every bit as"},{"speaker":"on Cosmic Vision","startTime":1097.61,"endTime":1101.63,"body":"successful as the first launch."},{"speaker":"on Cosmic Vision","startTime":1101.63,"endTime":1103.58,"body":"That's why we got that amazing image"},{"speaker":"on Cosmic Vision","startTime":1103.58,"endTime":1105.17,"body":"of Neptune and its rings"},{"speaker":"on Cosmic Vision","startTime":1105.17,"endTime":1107.603,"body":"that I showed you at the"},{"speaker":"on Cosmic Vision","startTime":1105.17,"endTime":1107.603,"body":"start of this lecture."},{"speaker":"on Cosmic Vision","startTime":1108.68,"endTime":1112.55,"body":"It is an absolute triumph of the expertise"},{"speaker":"on Cosmic Vision","startTime":1112.55,"endTime":1117.26,"body":"and the painstaking hard work"},{"speaker":"on Cosmic Vision","startTime":1112.55,"endTime":1117.26,"body":"of international cooperation"},{"speaker":"on Cosmic Vision","startTime":1117.26,"endTime":1121.43,"body":"by engineers, especially,"},{"speaker":"on Cosmic Vision","startTime":1117.26,"endTime":1121.43,"body":"and of scientists."},{"speaker":"on Cosmic Vision","startTime":1121.43,"endTime":1125.06,"body":"It's gone beautifully according to plan"},{"speaker":"on Cosmic Vision","startTime":1125.06,"endTime":1127.523,"body":"every step of the way since launch."},{"speaker":"on Cosmic Vision","startTime":1128.75,"endTime":1132.14,"body":"So, if we now look at the spectrum,"},{"speaker":"on Cosmic Vision","startTime":1132.14,"endTime":1136.28,"body":"the previous spectrum prior"},{"speaker":"on Cosmic Vision","startTime":1132.14,"endTime":1136.28,"body":"to the launch of the JWST,"},{"speaker":"on Cosmic Vision","startTime":1136.28,"endTime":1139.22,"body":"which is this one from"},{"speaker":"on Cosmic Vision","startTime":1136.28,"endTime":1139.22,"body":"the Spitzer satellite,"},{"speaker":"on Cosmic Vision","startTime":1139.22,"endTime":1141.44,"body":"and what the JWST brings."},{"speaker":"on Cosmic Vision","startTime":1141.44,"endTime":1143.96,"body":"That's the spectrum in these blue dots."},{"speaker":"on Cosmic Vision","startTime":1143.96,"endTime":1146.33,"body":"And I'm very grateful to"},{"speaker":"on Cosmic Vision","startTime":1143.96,"endTime":1146.33,"body":"my former graduate student,"},{"speaker":"on Cosmic Vision","startTime":1146.33,"endTime":1149.93,"body":"David Grant, for preparing this spectrum"},{"speaker":"on Cosmic Vision","startTime":1149.93,"endTime":1151.97,"body":"in such a clear way."},{"speaker":"on Cosmic Vision","startTime":1151.97,"endTime":1154.94,"body":"That big spike in blue dots there"},{"speaker":"on Cosmic Vision","startTime":1154.94,"endTime":1158.63,"body":"tells you about the presence of CO2"},{"speaker":"on Cosmic Vision","startTime":1158.63,"endTime":1162.74,"body":"at a wavelength of about 4.4 microns,"},{"speaker":"on Cosmic Vision","startTime":1162.74,"endTime":1166.133,"body":"4.4 millionths of a meter."},{"speaker":"on Cosmic Vision","startTime":1167.21,"endTime":1172.21,"body":"So CO2 in planetary"},{"speaker":"on Cosmic Vision","startTime":1167.21,"endTime":1172.21,"body":"atmospheres is a thing."},{"speaker":"on Cosmic Vision","startTime":1172.25,"endTime":1176.99,"body":"Practically the first exoplanet"},{"speaker":"on Cosmic Vision","startTime":1172.25,"endTime":1176.99,"body":"to be looked at showed CO2."},{"speaker":"on Cosmic Vision","startTime":1176.99,"endTime":1179.84,"body":"We had a slight hint"},{"speaker":"on Cosmic Vision","startTime":1176.99,"endTime":1179.84,"body":"that that was the case"},{"speaker":"on Cosmic Vision","startTime":1179.84,"endTime":1182.72,"body":"from a preexisting spectrum,"},{"speaker":"on Cosmic Vision","startTime":1182.72,"endTime":1185.303,"body":"but we now know for sure, very clearly,"},{"speaker":"on Cosmic Vision","startTime":1186.14,"endTime":1187.49,"body":"that there is CO2."},{"speaker":"on Cosmic Vision","startTime":1187.49,"endTime":1191.63,"body":"This spectrum is actually"},{"speaker":"on Cosmic Vision","startTime":1187.49,"endTime":1191.63,"body":"representing CO2 in absorption."},{"speaker":"on Cosmic Vision","startTime":1191.63,"endTime":1194.0,"body":"It doesn't matter too"},{"speaker":"on Cosmic Vision","startTime":1191.63,"endTime":1194.0,"body":"much about those details,"},{"speaker":"on Cosmic Vision","startTime":1194.0,"endTime":1195.05,"body":"but it's there."},{"speaker":"on Cosmic Vision","startTime":1195.05,"endTime":1199.943,"body":"It's in the atmosphere of"},{"speaker":"on Cosmic Vision","startTime":1195.05,"endTime":1199.943,"body":"that exoplanet, WASP-39b."},{"speaker":"on Cosmic Vision","startTime":1200.87,"endTime":1203.21,"body":"Well, now let's go back to Venus."},{"speaker":"on Cosmic Vision","startTime":1203.21,"endTime":1205.25,"body":"So, Venus."},{"speaker":"on Cosmic Vision","startTime":1205.25,"endTime":1210.25,"body":"This image is from NASA's"},{"speaker":"on Cosmic Vision","startTime":1205.25,"endTime":1210.25,"body":"Mariner 2 spacecraft."},{"speaker":"on Cosmic Vision","startTime":1210.29,"endTime":1214.52,"body":"It's got all the glamor of a"},{"speaker":"on Cosmic Vision","startTime":1210.29,"endTime":1214.52,"body":"slightly mucky ping pong ball,"},{"speaker":"on Cosmic Vision","startTime":1214.52,"endTime":1219.23,"body":"but it's vastly more deadly"},{"speaker":"on Cosmic Vision","startTime":1214.52,"endTime":1219.23,"body":"and hostile and dangerous"},{"speaker":"on Cosmic Vision","startTime":1219.23,"endTime":1222.35,"body":"because of all that CO2,"},{"speaker":"on Cosmic Vision","startTime":1222.35,"endTime":1227.35,"body":"because of the immense density of CO2."},{"speaker":"on Cosmic Vision","startTime":1227.66,"endTime":1232.66,"body":"It's 96% of CO2 in its atmosphere."},{"speaker":"on Cosmic Vision","startTime":1234.95,"endTime":1236.72,"body":"So, where does CO2 come from?"},{"speaker":"on Cosmic Vision","startTime":1236.72,"endTime":1241.43,"body":"And how come Venus has got"},{"speaker":"on Cosmic Vision","startTime":1236.72,"endTime":1241.43,"body":"so much CO2 in its atmosphere"},{"speaker":"on Cosmic Vision","startTime":1241.43,"endTime":1244.97,"body":"relative to, for example,"},{"speaker":"on Cosmic Vision","startTime":1241.43,"endTime":1244.97,"body":"what we have here on Earth?"},{"speaker":"on Cosmic Vision","startTime":1244.97,"endTime":1249.95,"body":"CO2 on Venus, CO2 on"},{"speaker":"on Cosmic Vision","startTime":1244.97,"endTime":1249.95,"body":"Earth, CO2 on other planets"},{"speaker":"on Cosmic Vision","startTime":1249.95,"endTime":1254.39,"body":"is very frequently released"},{"speaker":"on Cosmic Vision","startTime":1249.95,"endTime":1254.39,"body":"by volcanic activity."},{"speaker":"on Cosmic Vision","startTime":1254.39,"endTime":1258.533,"body":"Venus has way more volcanoes"},{"speaker":"on Cosmic Vision","startTime":1254.39,"endTime":1258.533,"body":"on it than Earth does."},{"speaker":"on Cosmic Vision","startTime":1259.76,"endTime":1261.713,"body":"Plate tectonic activity,"},{"speaker":"on Cosmic Vision","startTime":1263.144,"endTime":1265.4,"body":"when tectonic plates shift on a planet,"},{"speaker":"on Cosmic Vision","startTime":1265.4,"endTime":1270.4,"body":"can give rise to lots and"},{"speaker":"on Cosmic Vision","startTime":1265.4,"endTime":1270.4,"body":"lots of CO2 being released."},{"speaker":"on Cosmic Vision","startTime":1270.53,"endTime":1272.3,"body":"We no longer believe that Venus"},{"speaker":"on Cosmic Vision","startTime":1272.3,"endTime":1276.32,"body":"is seismically active these days,"},{"speaker":"on Cosmic Vision","startTime":1276.32,"endTime":1279.68,"body":"but we believe it was in the past."},{"speaker":"on Cosmic Vision","startTime":1279.68,"endTime":1284.68,"body":"So CO2, when released from"},{"speaker":"on Cosmic Vision","startTime":1279.68,"endTime":1284.68,"body":"volcanoes or tectonic activity,"},{"speaker":"on Cosmic Vision","startTime":1285.8,"endTime":1288.08,"body":"will make it into the atmosphere"},{"speaker":"on Cosmic Vision","startTime":1288.08,"endTime":1290.93,"body":"unless there's something to sequester it,"},{"speaker":"on Cosmic Vision","startTime":1290.93,"endTime":1293.093,"body":"unless there's something to store it."},{"speaker":"on Cosmic Vision","startTime":1294.05,"endTime":1295.76,"body":"What might be able to store CO2?"},{"speaker":"on Cosmic Vision","startTime":1295.76,"endTime":1297.65,"body":"Well, a nice big ocean."},{"speaker":"on Cosmic Vision","startTime":1297.65,"endTime":1300.773,"body":"We have wonderfully deep"},{"speaker":"on Cosmic Vision","startTime":1297.65,"endTime":1300.773,"body":"oceans here on Earth."},{"speaker":"on Cosmic Vision","startTime":1301.88,"endTime":1305.18,"body":"You can also, in contrast"},{"speaker":"on Cosmic Vision","startTime":1301.88,"endTime":1305.18,"body":"with Venus, by the way,"},{"speaker":"on Cosmic Vision","startTime":1305.18,"endTime":1308.3,"body":"Venus we don't believe"},{"speaker":"on Cosmic Vision","startTime":1305.18,"endTime":1308.3,"body":"ever had very deep oceans."},{"speaker":"on Cosmic Vision","startTime":1308.3,"endTime":1310.88,"body":"It has no oceans these days."},{"speaker":"on Cosmic Vision","startTime":1310.88,"endTime":1313.67,"body":"It's quite possible that they boiled off"},{"speaker":"on Cosmic Vision","startTime":1313.67,"endTime":1316.61,"body":"as the consequence of a"},{"speaker":"on Cosmic Vision","startTime":1313.67,"endTime":1316.61,"body":"runaway greenhouse effect."},{"speaker":"on Cosmic Vision","startTime":1316.61,"endTime":1319.07,"body":"More of that later on."},{"speaker":"on Cosmic Vision","startTime":1319.07,"endTime":1323.337,"body":"But plants and trees and"},{"speaker":"on Cosmic Vision","startTime":1319.07,"endTime":1323.337,"body":"animals can also sequester CO2."},{"speaker":"on Cosmic Vision","startTime":1325.601,"endTime":1330.38,"body":"CO2 can combine with water"},{"speaker":"on Cosmic Vision","startTime":1330.38,"endTime":1332.03,"body":"in the presence of sufficient energy"},{"speaker":"on Cosmic Vision","startTime":1332.03,"endTime":1335.42,"body":"and sufficient enzymes or catalysts"},{"speaker":"on Cosmic Vision","startTime":1335.42,"endTime":1337.28,"body":"in order to make the hydrocarbons"},{"speaker":"on Cosmic Vision","startTime":1337.28,"endTime":1341.0,"body":"that make up plants and trees and animals."},{"speaker":"on Cosmic Vision","startTime":1341.0,"endTime":1344.84,"body":"But Venus doesn't have"},{"speaker":"on Cosmic Vision","startTime":1341.0,"endTime":1344.84,"body":"any oceans to absorb CO2."},{"speaker":"on Cosmic Vision","startTime":1344.84,"endTime":1347.033,"body":"Earth's does, thankfully,"},{"speaker":"on Cosmic Vision","startTime":1347.99,"endTime":1352.07,"body":"and, at present, life is very much,"},{"speaker":"on Cosmic Vision","startTime":1352.07,"endTime":1355.133,"body":"for the most part, thriving here on Earth."},{"speaker":"on Cosmic Vision","startTime":1356.24,"endTime":1359.72,"body":"Let's talk a little more"},{"speaker":"on Cosmic Vision","startTime":1356.24,"endTime":1359.72,"body":"about some of the details"},{"speaker":"on Cosmic Vision","startTime":1359.72,"endTime":1363.23,"body":"of why Venus is so hostile to life."},{"speaker":"on Cosmic Vision","startTime":1363.23,"endTime":1366.83,"body":"That atmosphere that I"},{"speaker":"on Cosmic Vision","startTime":1363.23,"endTime":1366.83,"body":"mentioned that's 96% CO2."},{"speaker":"on Cosmic Vision","startTime":1366.83,"endTime":1370.61,"body":"It's not just the chemical"},{"speaker":"on Cosmic Vision","startTime":1366.83,"endTime":1370.61,"body":"composition of the atmosphere"},{"speaker":"on Cosmic Vision","startTime":1370.61,"endTime":1372.74,"body":"that would be deadly to life."},{"speaker":"on Cosmic Vision","startTime":1372.74,"endTime":1376.583,"body":"It's also that Venus has extreme pressure."},{"speaker":"on Cosmic Vision","startTime":1377.9,"endTime":1380.72,"body":"The atmospheric pressure"},{"speaker":"on Cosmic Vision","startTime":1377.9,"endTime":1380.72,"body":"that we have here on Earth"},{"speaker":"on Cosmic Vision","startTime":1380.72,"endTime":1382.43,"body":"is pretty good at sea level."},{"speaker":"on Cosmic Vision","startTime":1382.43,"endTime":1384.2,"body":"It's about right."},{"speaker":"on Cosmic Vision","startTime":1384.2,"endTime":1387.17,"body":"It's a bit strenuous to operate in"},{"speaker":"on Cosmic Vision","startTime":1387.17,"endTime":1389.81,"body":"on some of Earth's highest mountains,"},{"speaker":"on Cosmic Vision","startTime":1389.81,"endTime":1392.33,"body":"on Mauna Kea on Hawaii, for example,"},{"speaker":"on Cosmic Vision","startTime":1392.33,"endTime":1396.113,"body":"or Mauna Loa, or some of"},{"speaker":"on Cosmic Vision","startTime":1392.33,"endTime":1396.113,"body":"the high mountains in Chile."},{"speaker":"on Cosmic Vision","startTime":1397.13,"endTime":1402.13,"body":"But the pressure on the surface"},{"speaker":"on Cosmic Vision","startTime":1397.13,"endTime":1402.13,"body":"of Venus is 90 times higher"},{"speaker":"on Cosmic Vision","startTime":1403.19,"endTime":1406.88,"body":"than the atmospheric pressure on Earth."},{"speaker":"on Cosmic Vision","startTime":1406.88,"endTime":1410.99,"body":"It's equivalent to the"},{"speaker":"on Cosmic Vision","startTime":1406.88,"endTime":1410.99,"body":"pressure that you would get"},{"speaker":"on Cosmic Vision","startTime":1410.99,"endTime":1415.28,"body":"if you were about one"},{"speaker":"on Cosmic Vision","startTime":1410.99,"endTime":1415.28,"body":"kilometer deep in our ocean."},{"speaker":"on Cosmic Vision","startTime":1415.28,"endTime":1418.493,"body":"You'd be crushed. You would not survive."},{"speaker":"on Cosmic Vision","startTime":1419.54,"endTime":1423.15,"body":"Another way in which"},{"speaker":"on Cosmic Vision","startTime":1419.54,"endTime":1423.15,"body":"Venus is way too hostile"},{"speaker":"on Cosmic Vision","startTime":1425.388,"endTime":1429.59,"body":"for life to survive is"},{"speaker":"on Cosmic Vision","startTime":1425.388,"endTime":1429.59,"body":"its extreme temperatures."},{"speaker":"on Cosmic Vision","startTime":1429.59,"endTime":1431.48,"body":"All of that CO2,"},{"speaker":"on Cosmic Vision","startTime":1431.48,"endTime":1435.83,"body":"all of the clouds that I"},{"speaker":"on Cosmic Vision","startTime":1431.48,"endTime":1435.83,"body":"mentioned keep heat in."},{"speaker":"on Cosmic Vision","startTime":1435.83,"endTime":1437.6,"body":"They trap heat in."},{"speaker":"on Cosmic Vision","startTime":1437.6,"endTime":1439.88,"body":"More of that a bit later on."},{"speaker":"on Cosmic Vision","startTime":1439.88,"endTime":1443.03,"body":"But the temperature at"},{"speaker":"on Cosmic Vision","startTime":1439.88,"endTime":1443.03,"body":"the surface of Venus"},{"speaker":"on Cosmic Vision","startTime":1443.03,"endTime":1446.87,"body":"is about 460 degrees Celsius."},{"speaker":"on Cosmic Vision","startTime":1446.87,"endTime":1449.0,"body":"That's way hotter than my oven,"},{"speaker":"on Cosmic Vision","startTime":1449.0,"endTime":1450.713,"body":"and I have a pretty fancy oven."},{"speaker":"on Cosmic Vision","startTime":1452.3,"endTime":1457.3,"body":"460 degrees Celsius is hotter"},{"speaker":"on Cosmic Vision","startTime":1452.3,"endTime":1457.3,"body":"than lead can survive in."},{"speaker":"on Cosmic Vision","startTime":1458.69,"endTime":1463.69,"body":"460 degrees Celsius is above"},{"speaker":"on Cosmic Vision","startTime":1458.69,"endTime":1463.69,"body":"the melting point of lead."},{"speaker":"on Cosmic Vision","startTime":1464.42,"endTime":1469.28,"body":"No way would life or humans survive."},{"speaker":"on Cosmic Vision","startTime":1469.28,"endTime":1473.6,"body":"And amid these extreme"},{"speaker":"on Cosmic Vision","startTime":1469.28,"endTime":1473.6,"body":"temperatures, there is no relief"},{"speaker":"on Cosmic Vision","startTime":1473.6,"endTime":1477.08,"body":"because days last so long."},{"speaker":"on Cosmic Vision","startTime":1477.08,"endTime":1479.543,"body":"There's no cooling off at night."},{"speaker":"on Cosmic Vision","startTime":1480.98,"endTime":1483.29,"body":"There's very little annual variation"},{"speaker":"on Cosmic Vision","startTime":1483.29,"endTime":1485.9,"body":"because the tilt of Venus' axis,"},{"speaker":"on Cosmic Vision","startTime":1485.9,"endTime":1489.56,"body":"about which it spins jolly slowly,"},{"speaker":"on Cosmic Vision","startTime":1489.56,"endTime":1492.44,"body":"is none of this 28 degrees"},{"speaker":"on Cosmic Vision","startTime":1489.56,"endTime":1492.44,"body":"that you have on Neptune"},{"speaker":"on Cosmic Vision","startTime":1492.44,"endTime":1495.32,"body":"or 23 degrees that you have on Earth."},{"speaker":"on Cosmic Vision","startTime":1495.32,"endTime":1496.73,"body":"It's three degrees,"},{"speaker":"on Cosmic Vision","startTime":1496.73,"endTime":1499.34,"body":"so you don't even get seasons"},{"speaker":"on Cosmic Vision","startTime":1499.34,"endTime":1502.673,"body":"and a cool winter season"},{"speaker":"on Cosmic Vision","startTime":1499.34,"endTime":1502.673,"body":"in which to cool off."},{"speaker":"on Cosmic Vision","startTime":1505.82,"endTime":1509.21,"body":"It's been suggested that"},{"speaker":"on Cosmic Vision","startTime":1505.82,"endTime":1509.21,"body":"the Venus atmosphere"},{"speaker":"on Cosmic Vision","startTime":1509.21,"endTime":1512.3,"body":"has been so hot in the past"},{"speaker":"on Cosmic Vision","startTime":1512.3,"endTime":1516.14,"body":"that hydrogen cannot"},{"speaker":"on Cosmic Vision","startTime":1512.3,"endTime":1516.14,"body":"remain in its atmosphere."},{"speaker":"on Cosmic Vision","startTime":1516.14,"endTime":1519.68,"body":"And the reason for this"},{"speaker":"on Cosmic Vision","startTime":1516.14,"endTime":1519.68,"body":"is that we know the ratio"},{"speaker":"on Cosmic Vision","startTime":1519.68,"endTime":1522.44,"body":"of H2O, gaseous water,"},{"speaker":"on Cosmic Vision","startTime":1522.44,"endTime":1525.17,"body":"and D2O, which is like water,"},{"speaker":"on Cosmic Vision","startTime":1525.17,"endTime":1527.18,"body":"but where, instead of hydrogen,"},{"speaker":"on Cosmic Vision","startTime":1527.18,"endTime":1531.05,"body":"you've got what's called"},{"speaker":"on Cosmic Vision","startTime":1527.18,"endTime":1531.05,"body":"heavy hydrogen, deuterium,"},{"speaker":"on Cosmic Vision","startTime":1531.05,"endTime":1533.24,"body":"which is chemically the same as hydrogen"},{"speaker":"on Cosmic Vision","startTime":1533.24,"endTime":1535.43,"body":"but much more massive."},{"speaker":"on Cosmic Vision","startTime":1535.43,"endTime":1539.63,"body":"And while you have"},{"speaker":"on Cosmic Vision","startTime":1535.43,"endTime":1539.63,"body":"something like 100 times"},{"speaker":"on Cosmic Vision","startTime":1539.63,"endTime":1544.1,"body":"the D2O to H2O ratio on Venus"},{"speaker":"on Cosmic Vision","startTime":1544.1,"endTime":1547.13,"body":"compared with what you"},{"speaker":"on Cosmic Vision","startTime":1544.1,"endTime":1547.13,"body":"have on planet Earth,"},{"speaker":"on Cosmic Vision","startTime":1547.13,"endTime":1549.23,"body":"even though we think Venus and Earth"},{"speaker":"on Cosmic Vision","startTime":1549.23,"endTime":1551.87,"body":"formed out of the same bit of gas cloud"},{"speaker":"on Cosmic Vision","startTime":1551.87,"endTime":1554.87,"body":"that gave rise to our solar system,"},{"speaker":"on Cosmic Vision","startTime":1554.87,"endTime":1558.2,"body":"we think that, because the"},{"speaker":"on Cosmic Vision","startTime":1554.87,"endTime":1558.2,"body":"atmosphere of Venus was so hot,"},{"speaker":"on Cosmic Vision","startTime":1558.2,"endTime":1560.72,"body":"the hydrogen was able to escape"},{"speaker":"on Cosmic Vision","startTime":1560.72,"endTime":1563.63,"body":"in a phenomenon known"},{"speaker":"on Cosmic Vision","startTime":1560.72,"endTime":1563.63,"body":"in planetary atmospheres"},{"speaker":"on Cosmic Vision","startTime":1563.63,"endTime":1565.793,"body":"as Jeans escape."},{"speaker":"on Cosmic Vision","startTime":1568.82,"endTime":1572.12,"body":"So Venus, I hope I've convinced you,"},{"speaker":"on Cosmic Vision","startTime":1572.12,"endTime":1575.15,"body":"is absolutely deadly to humans"},{"speaker":"on Cosmic Vision","startTime":1575.15,"endTime":1577.943,"body":"and absolutely deadly to everything else."},{"speaker":"on Cosmic Vision","startTime":1579.05,"endTime":1583.01,"body":"Let's now start to make some"},{"speaker":"on Cosmic Vision","startTime":1579.05,"endTime":1583.01,"body":"comparisons with planet Earth."},{"speaker":"on Cosmic Vision","startTime":1583.01,"endTime":1587.48,"body":"How much CO2 is in Earth's atmosphere?"},{"speaker":"on Cosmic Vision","startTime":1587.48,"endTime":1588.89,"body":"I'm sure we're all relieved to know"},{"speaker":"on Cosmic Vision","startTime":1588.89,"endTime":1592.76,"body":"that it's much less than in planet Venus,"},{"speaker":"on Cosmic Vision","startTime":1592.76,"endTime":1595.28,"body":"but let's just consider"},{"speaker":"on Cosmic Vision","startTime":1592.76,"endTime":1595.28,"body":"how much less there is,"},{"speaker":"on Cosmic Vision","startTime":1595.28,"endTime":1598.37,"body":"how much less CO2 there is."},{"speaker":"on Cosmic Vision","startTime":1598.37,"endTime":1603.37,"body":"The units we normally use for"},{"speaker":"on Cosmic Vision","startTime":1598.37,"endTime":1603.37,"body":"CO2 are parts per million,"},{"speaker":"on Cosmic Vision","startTime":1603.38,"endTime":1604.54,"body":"parts of..."},{"speaker":"on Cosmic Vision","startTime":1606.17,"endTime":1609.62,"body":"You ratio the number of CO2 molecules"},{"speaker":"on Cosmic Vision","startTime":1609.62,"endTime":1612.77,"body":"relative to other particles"},{"speaker":"on Cosmic Vision","startTime":1609.62,"endTime":1612.77,"body":"in the atmosphere,"},{"speaker":"on Cosmic Vision","startTime":1612.77,"endTime":1614.9,"body":"whether they're nitrogen or oxygen"},{"speaker":"on Cosmic Vision","startTime":1614.9,"endTime":1617.36,"body":"or whatever else it might be."},{"speaker":"on Cosmic Vision","startTime":1617.36,"endTime":1621.5,"body":"The parts per million"},{"speaker":"on Cosmic Vision","startTime":1617.36,"endTime":1621.5,"body":"of CO2, carbon dioxide,"},{"speaker":"on Cosmic Vision","startTime":1621.5,"endTime":1625.34,"body":"in Earth's atmosphere"},{"speaker":"on Cosmic Vision","startTime":1621.5,"endTime":1625.34,"body":"has been rising steadily"},{"speaker":"on Cosmic Vision","startTime":1625.34,"endTime":1628.34,"body":"since the start of the"},{"speaker":"on Cosmic Vision","startTime":1625.34,"endTime":1628.34,"body":"Industrial Revolution"},{"speaker":"on Cosmic Vision","startTime":1628.34,"endTime":1631.22,"body":"and has climbed really quite dramatically"},{"speaker":"on Cosmic Vision","startTime":1631.22,"endTime":1633.653,"body":"in the last several decades."},{"speaker":"on Cosmic Vision","startTime":1635.15,"endTime":1638.18,"body":"The parts per million of CO2,"},{"speaker":"on Cosmic Vision","startTime":1638.18,"endTime":1640.413,"body":"now well over 400,"},{"speaker":"on Cosmic Vision","startTime":1640.413,"endTime":1643.28,"body":"there are about 420 parts per million,"},{"speaker":"on Cosmic Vision","startTime":1643.28,"endTime":1645.77,"body":"have risen by about a third"},{"speaker":"on Cosmic Vision","startTime":1645.77,"endTime":1649.73,"body":"since Queen Elizabeth II"},{"speaker":"on Cosmic Vision","startTime":1645.77,"endTime":1649.73,"body":"ascended to the throne"},{"speaker":"on Cosmic Vision","startTime":1649.73,"endTime":1652.76,"body":"and by about 50% since the start"},{"speaker":"on Cosmic Vision","startTime":1652.76,"endTime":1654.473,"body":"of the Industrial Revolution."},{"speaker":"on Cosmic Vision","startTime":1655.7,"endTime":1660.26,"body":"This plot here shows the"},{"speaker":"on Cosmic Vision","startTime":1655.7,"endTime":1660.26,"body":"parts per million of CO2"},{"speaker":"on Cosmic Vision","startTime":1660.26,"endTime":1662.09,"body":"at pretty much today's date."},{"speaker":"on Cosmic Vision","startTime":1662.09,"endTime":1665.99,"body":"This was up to date earlier this summer."},{"speaker":"on Cosmic Vision","startTime":1665.99,"endTime":1669.92,"body":"And you can see the black"},{"speaker":"on Cosmic Vision","startTime":1665.99,"endTime":1669.92,"body":"line is the sort of steady fit"},{"speaker":"on Cosmic Vision","startTime":1669.92,"endTime":1674.92,"body":"averaged over full 12-month"},{"speaker":"on Cosmic Vision","startTime":1669.92,"endTime":1674.92,"body":"periods, over complete years,"},{"speaker":"on Cosmic Vision","startTime":1676.22,"endTime":1680.6,"body":"and the red zigzags tells you"},{"speaker":"on Cosmic Vision","startTime":1676.22,"endTime":1680.6,"body":"about the annual variation"},{"speaker":"on Cosmic Vision","startTime":1680.6,"endTime":1683.153,"body":"that you get, that has"},{"speaker":"on Cosmic Vision","startTime":1680.6,"endTime":1683.153,"body":"been known for some time."},{"speaker":"on Cosmic Vision","startTime":1684.02,"endTime":1686.42,"body":"It rises and it falls each year."},{"speaker":"on Cosmic Vision","startTime":1686.42,"endTime":1689.0,"body":"It falls each year because"},{"speaker":"on Cosmic Vision","startTime":1686.42,"endTime":1689.0,"body":"of the growing season"},{"speaker":"on Cosmic Vision","startTime":1689.0,"endTime":1690.47,"body":"in the Northern Hemisphere."},{"speaker":"on Cosmic Vision","startTime":1690.47,"endTime":1693.62,"body":"The Northern Hemisphere of"},{"speaker":"on Cosmic Vision","startTime":1690.47,"endTime":1693.62,"body":"Earth has much more land,"},{"speaker":"on Cosmic Vision","startTime":1693.62,"endTime":1696.35,"body":"and the Southern Hemisphere"},{"speaker":"on Cosmic Vision","startTime":1693.62,"endTime":1696.35,"body":"has much more sea."},{"speaker":"on Cosmic Vision","startTime":1696.35,"endTime":1697.91,"body":"Sea doesn't do that much growing,"},{"speaker":"on Cosmic Vision","startTime":1697.91,"endTime":1700.49,"body":"but the growing period on"},{"speaker":"on Cosmic Vision","startTime":1697.91,"endTime":1700.49,"body":"the Northern Hemisphere"},{"speaker":"on Cosmic Vision","startTime":1700.49,"endTime":1704.15,"body":"is responsible for attenuating that fall,"},{"speaker":"on Cosmic Vision","startTime":1704.15,"endTime":1709.15,"body":"but, of course, it's superimposed"},{"speaker":"on Cosmic Vision","startTime":1704.15,"endTime":1709.15,"body":"on an increasing rise."},{"speaker":"on Cosmic Vision","startTime":1709.61,"endTime":1713.3,"body":"The reason is that plants"},{"speaker":"on Cosmic Vision","startTime":1709.61,"endTime":1713.3,"body":"use CO2 from the atmosphere"},{"speaker":"on Cosmic Vision","startTime":1713.3,"endTime":1716.45,"body":"along with sunlight and water to make food"},{"speaker":"on Cosmic Vision","startTime":1716.45,"endTime":1720.8,"body":"and to make hydrocarbons and substances"},{"speaker":"on Cosmic Vision","startTime":1720.8,"endTime":1722.243,"body":"that they need to grow."},{"speaker":"on Cosmic Vision","startTime":1723.11,"endTime":1725.96,"body":"This is the chemical"},{"speaker":"on Cosmic Vision","startTime":1723.11,"endTime":1725.96,"body":"reaction that's undergoing."},{"speaker":"on Cosmic Vision","startTime":1725.96,"endTime":1729.23,"body":"CO2 and water and, sorry,"},{"speaker":"on Cosmic Vision","startTime":1725.96,"endTime":1729.23,"body":"that should say energy."},{"speaker":"on Cosmic Vision","startTime":1729.23,"endTime":1731.24,"body":"I apologize. It's not very visible."},{"speaker":"on Cosmic Vision","startTime":1731.24,"endTime":1735.14,"body":"Give rise to the hydrocarbons,"},{"speaker":"on Cosmic Vision","startTime":1731.24,"endTime":1735.14,"body":"the complex molecules"},{"speaker":"on Cosmic Vision","startTime":1735.14,"endTime":1739.01,"body":"involving carbon and hydrogen and oxygen."},{"speaker":"on Cosmic Vision","startTime":1739.01,"endTime":1742.61,"body":"And oxygen is usually"},{"speaker":"on Cosmic Vision","startTime":1739.01,"endTime":1742.61,"body":"released in that process"},{"speaker":"on Cosmic Vision","startTime":1742.61,"endTime":1744.17,"body":"because of the different ratios,"},{"speaker":"on Cosmic Vision","startTime":1744.17,"endTime":1747.443,"body":"the stoichiometry of the"},{"speaker":"on Cosmic Vision","startTime":1744.17,"endTime":1747.443,"body":"molecules that get made."},{"speaker":"on Cosmic Vision","startTime":1748.37,"endTime":1751.313,"body":"So plants sequester CO2,"},{"speaker":"on Cosmic Vision","startTime":1752.69,"endTime":1756.41,"body":"and then CO2 is stored as hydrocarbons"},{"speaker":"on Cosmic Vision","startTime":1756.41,"endTime":1758.123,"body":"in plants and trees."},{"speaker":"on Cosmic Vision","startTime":1759.35,"endTime":1762.71,"body":"So let's ask the question now."},{"speaker":"on Cosmic Vision","startTime":1762.71,"endTime":1766.13,"body":"Is 420 parts per million of CO2"},{"speaker":"on Cosmic Vision","startTime":1766.13,"endTime":1768.65,"body":"in Earth's atmosphere significant,"},{"speaker":"on Cosmic Vision","startTime":1768.65,"endTime":1771.44,"body":"even allowing for our relief"},{"speaker":"on Cosmic Vision","startTime":1771.44,"endTime":1775.25,"body":"at the fact that the CO2"},{"speaker":"on Cosmic Vision","startTime":1771.44,"endTime":1775.25,"body":"quantity in our atmosphere"},{"speaker":"on Cosmic Vision","startTime":1775.25,"endTime":1779.3,"body":"is not as deadly as the percentage of 96%"},{"speaker":"on Cosmic Vision","startTime":1779.3,"endTime":1780.923,"body":"that there is in Venus?"},{"speaker":"on Cosmic Vision","startTime":1782.18,"endTime":1786.26,"body":"Anyone who's tempted to think"},{"speaker":"on Cosmic Vision","startTime":1782.18,"endTime":1786.26,"body":"that 400 parts per million"},{"speaker":"on Cosmic Vision","startTime":1786.26,"endTime":1790.2,"body":"of CO2 in our atmosphere"},{"speaker":"on Cosmic Vision","startTime":1786.26,"endTime":1790.2,"body":"is not significant"},{"speaker":"on Cosmic Vision","startTime":1791.3,"endTime":1792.98,"body":"should be confronted with the following."},{"speaker":"on Cosmic Vision","startTime":1792.98,"endTime":1796.4,"body":"If you think 400 parts of anything"},{"speaker":"on Cosmic Vision","startTime":1796.4,"endTime":1800.63,"body":"amid a million parts of other"},{"speaker":"on Cosmic Vision","startTime":1796.4,"endTime":1800.63,"body":"stuff is not significant,"},{"speaker":"on Cosmic Vision","startTime":1800.63,"endTime":1802.22,"body":"probably isn't a coffee drinker."},{"speaker":"on Cosmic Vision","startTime":1802.22,"endTime":1803.21,"body":"Why do I say that?"},{"speaker":"on Cosmic Vision","startTime":1803.21,"endTime":1807.98,"body":"Well, 400 parts per million of caffeine"},{"speaker":"on Cosmic Vision","startTime":1807.98,"endTime":1810.32,"body":"is very significant to those of us"},{"speaker":"on Cosmic Vision","startTime":1810.32,"endTime":1813.14,"body":"who are very definitely"},{"speaker":"on Cosmic Vision","startTime":1810.32,"endTime":1813.14,"body":"in need of a cup of coffee"},{"speaker":"on Cosmic Vision","startTime":1813.14,"endTime":1815.75,"body":"when booting up this morning."},{"speaker":"on Cosmic Vision","startTime":1815.75,"endTime":1819.41,"body":"If you don't believe me,"},{"speaker":"on Cosmic Vision","startTime":1815.75,"endTime":1819.41,"body":"then tomorrow morning,"},{"speaker":"on Cosmic Vision","startTime":1819.41,"endTime":1821.69,"body":"when you're in need of a cup of coffee,"},{"speaker":"on Cosmic Vision","startTime":1821.69,"endTime":1823.223,"body":"try drinking decaf."},{"speaker":"on Cosmic Vision","startTime":1825.14,"endTime":1827.24,"body":"A normal cup of coffee contains"},{"speaker":"on Cosmic Vision","startTime":1827.24,"endTime":1831.56,"body":"about 400 parts per million of CO2."},{"speaker":"on Cosmic Vision","startTime":1831.56,"endTime":1832.91,"body":"Sorry, let's try that again."},{"speaker":"on Cosmic Vision","startTime":1832.91,"endTime":1835.34,"body":"A normal cup of coffee contains"},{"speaker":"on Cosmic Vision","startTime":1835.34,"endTime":1839.51,"body":"about 400 parts per million"},{"speaker":"on Cosmic Vision","startTime":1835.34,"endTime":1839.51,"body":"of caffeine molecules"},{"speaker":"on Cosmic Vision","startTime":1839.51,"endTime":1842.63,"body":"amongst all the water molecules"},{"speaker":"on Cosmic Vision","startTime":1839.51,"endTime":1842.63,"body":"and milk, if you take it,"},{"speaker":"on Cosmic Vision","startTime":1842.63,"endTime":1844.52,"body":"and all that sort of thing."},{"speaker":"on Cosmic Vision","startTime":1844.52,"endTime":1846.77,"body":"So I put it too you,"},{"speaker":"on Cosmic Vision","startTime":1844.52,"endTime":1846.77,"body":"there's a big difference"},{"speaker":"on Cosmic Vision","startTime":1846.77,"endTime":1848.75,"body":"between caffeinated coffee,"},{"speaker":"on Cosmic Vision","startTime":1848.75,"endTime":1850.91,"body":"which has about 400 parts per million"},{"speaker":"on Cosmic Vision","startTime":1850.91,"endTime":1854.51,"body":"of caffeine molecules, and decaf."},{"speaker":"on Cosmic Vision","startTime":1854.51,"endTime":1855.65,"body":"I should, of course, acknowledge"},{"speaker":"on Cosmic Vision","startTime":1855.65,"endTime":1857.78,"body":"that this is a culturally"},{"speaker":"on Cosmic Vision","startTime":1855.65,"endTime":1857.78,"body":"dependent statement"},{"speaker":"on Cosmic Vision","startTime":1857.78,"endTime":1860.93,"body":"because Italian coffee has"},{"speaker":"on Cosmic Vision","startTime":1857.78,"endTime":1860.93,"body":"a much higher concentration"},{"speaker":"on Cosmic Vision","startTime":1860.93,"endTime":1864.68,"body":"of caffeine molecules and"},{"speaker":"on Cosmic Vision","startTime":1860.93,"endTime":1864.68,"body":"in certain places in the US"},{"speaker":"on Cosmic Vision","startTime":1864.68,"endTime":1867.143,"body":"coffee contains rather less caffeine."},{"speaker":"on Cosmic Vision","startTime":1869.48,"endTime":1871.61,"body":"So I want to think now about whether,"},{"speaker":"on Cosmic Vision","startTime":1871.61,"endTime":1874.1,"body":"if we've got a tiny amount of CO2"},{"speaker":"on Cosmic Vision","startTime":1874.1,"endTime":1876.74,"body":"in the atmosphere on planet Earth,"},{"speaker":"on Cosmic Vision","startTime":1876.74,"endTime":1878.57,"body":"can it be significant?"},{"speaker":"on Cosmic Vision","startTime":1878.57,"endTime":1881.57,"body":"Can it give rise to feedback processes"},{"speaker":"on Cosmic Vision","startTime":1881.57,"endTime":1885.68,"body":"which thereby alter or"},{"speaker":"on Cosmic Vision","startTime":1881.57,"endTime":1885.68,"body":"have the potential to alter"},{"speaker":"on Cosmic Vision","startTime":1885.68,"endTime":1890.45,"body":"the nature of the"},{"speaker":"on Cosmic Vision","startTime":1885.68,"endTime":1890.45,"body":"atmosphere on planet Earth?"},{"speaker":"on Cosmic Vision","startTime":1890.45,"endTime":1893.75,"body":"I want to talk about two"},{"speaker":"on Cosmic Vision","startTime":1890.45,"endTime":1893.75,"body":"distinctive phenomena,"},{"speaker":"on Cosmic Vision","startTime":1893.75,"endTime":1896.63,"body":"two distinctive feedback processes,"},{"speaker":"on Cosmic Vision","startTime":1896.63,"endTime":1899.693,"body":"which are well known in, for"},{"speaker":"on Cosmic Vision","startTime":1896.63,"endTime":1899.693,"body":"example, system engineering."},{"speaker":"on Cosmic Vision","startTime":1900.56,"endTime":1903.41,"body":"The first of these is something"},{"speaker":"on Cosmic Vision","startTime":1900.56,"endTime":1903.41,"body":"we call positive feedback."},{"speaker":"on Cosmic Vision","startTime":1903.41,"endTime":1906.59,"body":"Now, you might be tempted to"},{"speaker":"on Cosmic Vision","startTime":1903.41,"endTime":1906.59,"body":"think that positive feedback"},{"speaker":"on Cosmic Vision","startTime":1906.59,"endTime":1907.61,"body":"is a good thing."},{"speaker":"on Cosmic Vision","startTime":1907.61,"endTime":1910.79,"body":"I'd like to pour cold water"},{"speaker":"on Cosmic Vision","startTime":1907.61,"endTime":1910.79,"body":"on that straight away."},{"speaker":"on Cosmic Vision","startTime":1910.79,"endTime":1913.91,"body":"Positive feedback is not a good thing"},{"speaker":"on Cosmic Vision","startTime":1913.91,"endTime":1916.34,"body":"because it reinforces the thing"},{"speaker":"on Cosmic Vision","startTime":1916.34,"endTime":1917.933,"body":"that you'd rather have less of."},{"speaker":"on Cosmic Vision","startTime":1918.92,"endTime":1922.28,"body":"Let me give you an example"},{"speaker":"on Cosmic Vision","startTime":1918.92,"endTime":1922.28,"body":"from everyday life."},{"speaker":"on Cosmic Vision","startTime":1922.28,"endTime":1924.35,"body":"Supposing you can't sleep"},{"speaker":"on Cosmic Vision","startTime":1924.35,"endTime":1926.84,"body":"because you're anxious about something,"},{"speaker":"on Cosmic Vision","startTime":1926.84,"endTime":1928.88,"body":"and then you become anxious"},{"speaker":"on Cosmic Vision","startTime":1928.88,"endTime":1931.43,"body":"about the fact you're not sleeping,"},{"speaker":"on Cosmic Vision","startTime":1931.43,"endTime":1935.09,"body":"and so you become more"},{"speaker":"on Cosmic Vision","startTime":1931.43,"endTime":1935.09,"body":"awake, and you can't sleep,"},{"speaker":"on Cosmic Vision","startTime":1935.09,"endTime":1937.73,"body":"and that increases the anxiety levels."},{"speaker":"on Cosmic Vision","startTime":1937.73,"endTime":1940.4,"body":"I'm sure many of us have been there."},{"speaker":"on Cosmic Vision","startTime":1940.4,"endTime":1942.47,"body":"That's positive feedback,"},{"speaker":"on Cosmic Vision","startTime":1942.47,"endTime":1946.94,"body":"where you reinforce a vicious cycle."},{"speaker":"on Cosmic Vision","startTime":1946.94,"endTime":1950.21,"body":"The same thing happens in the context"},{"speaker":"on Cosmic Vision","startTime":1950.21,"endTime":1952.19,"body":"of atmospheric physics."},{"speaker":"on Cosmic Vision","startTime":1952.19,"endTime":1956.81,"body":"If something is causing the"},{"speaker":"on Cosmic Vision","startTime":1952.19,"endTime":1956.81,"body":"planet to warm up a bit,"},{"speaker":"on Cosmic Vision","startTime":1956.81,"endTime":1961.81,"body":"then you are at risk of"},{"speaker":"on Cosmic Vision","startTime":1956.81,"endTime":1961.81,"body":"melting the polar ice caps."},{"speaker":"on Cosmic Vision","startTime":1963.59,"endTime":1967.97,"body":"Remember I said earlier that"},{"speaker":"on Cosmic Vision","startTime":1963.59,"endTime":1967.97,"body":"ice has a really high albedo."},{"speaker":"on Cosmic Vision","startTime":1967.97,"endTime":1971.12,"body":"It reflects a lot of"},{"speaker":"on Cosmic Vision","startTime":1967.97,"endTime":1971.12,"body":"sunlight back into space."},{"speaker":"on Cosmic Vision","startTime":1971.12,"endTime":1973.67,"body":"If you lose that and it becomes sea water,"},{"speaker":"on Cosmic Vision","startTime":1973.67,"endTime":1975.41,"body":"there's a load of bad stuff that happens"},{"speaker":"on Cosmic Vision","startTime":1975.41,"endTime":1978.83,"body":"because the sea levels increase,"},{"speaker":"on Cosmic Vision","startTime":1978.83,"endTime":1982.31,"body":"and that encroaches on the"},{"speaker":"on Cosmic Vision","startTime":1978.83,"endTime":1982.31,"body":"land where humans are living,"},{"speaker":"on Cosmic Vision","startTime":1982.31,"endTime":1986.48,"body":"particularly in very low"},{"speaker":"on Cosmic Vision","startTime":1982.31,"endTime":1986.48,"body":"lying places like Bangladesh."},{"speaker":"on Cosmic Vision","startTime":1986.48,"endTime":1990.5,"body":"But, in addition,"},{"speaker":"on Cosmic Vision","startTime":1986.48,"endTime":1990.5,"body":"Earth's albedo goes down."},{"speaker":"on Cosmic Vision","startTime":1990.5,"endTime":1995.193,"body":"Less sunlight is reflected,"},{"speaker":"on Cosmic Vision","startTime":1990.5,"endTime":1995.193,"body":"and so the planet heats up."},{"speaker":"on Cosmic Vision","startTime":1996.29,"endTime":1999.53,"body":"That happens because less solar energy,"},{"speaker":"on Cosmic Vision","startTime":1999.53,"endTime":2002.08,"body":"less sunlight is reflected,"},{"speaker":"on Cosmic Vision","startTime":2002.08,"endTime":2004.63,"body":"and so the globe warms,"},{"speaker":"on Cosmic Vision","startTime":2004.63,"endTime":2009.04,"body":"and so more ice on the ice caps can melt."},{"speaker":"on Cosmic Vision","startTime":2009.04,"endTime":2011.59,"body":"This is called positive feedback"},{"speaker":"on Cosmic Vision","startTime":2011.59,"endTime":2014.08,"body":"because it reinforces the bad thing"},{"speaker":"on Cosmic Vision","startTime":2014.08,"endTime":2015.98,"body":"you really don't want to be happening."},{"speaker":"on Cosmic Vision","startTime":2017.59,"endTime":2020.17,"body":"Is positive feedback a good thing?"},{"speaker":"on Cosmic Vision","startTime":2020.17,"endTime":2022.06,"body":"It's really not,"},{"speaker":"on Cosmic Vision","startTime":2022.06,"endTime":2025.12,"body":"and it's a process that"},{"speaker":"on Cosmic Vision","startTime":2022.06,"endTime":2025.12,"body":"is very much at play"},{"speaker":"on Cosmic Vision","startTime":2025.12,"endTime":2029.02,"body":"in all sorts of different"},{"speaker":"on Cosmic Vision","startTime":2025.12,"endTime":2029.02,"body":"ways in Earth's atmosphere,"},{"speaker":"on Cosmic Vision","startTime":2029.02,"endTime":2031.0,"body":"in all planetary atmospheres."},{"speaker":"on Cosmic Vision","startTime":2031.0,"endTime":2034.87,"body":"Almost certainly, if there"},{"speaker":"on Cosmic Vision","startTime":2031.0,"endTime":2034.87,"body":"ever were oceans in Venus,"},{"speaker":"on Cosmic Vision","startTime":2034.87,"endTime":2039.79,"body":"this kind of spiral led"},{"speaker":"on Cosmic Vision","startTime":2034.87,"endTime":2039.79,"body":"to the deadly situation,"},{"speaker":"on Cosmic Vision","startTime":2039.79,"endTime":2044.2,"body":"the hellish situation"},{"speaker":"on Cosmic Vision","startTime":2039.79,"endTime":2044.2,"body":"that we now have on Venus."},{"speaker":"on Cosmic Vision","startTime":2044.2,"endTime":2046.39,"body":"So that's positive feedback,"},{"speaker":"on Cosmic Vision","startTime":2046.39,"endTime":2049.36,"body":"and we need to remember"},{"speaker":"on Cosmic Vision","startTime":2046.39,"endTime":2049.36,"body":"positive feedback is really bad."},{"speaker":"on Cosmic Vision","startTime":2049.36,"endTime":2054.36,"body":"So anything that promotes the"},{"speaker":"on Cosmic Vision","startTime":2049.36,"endTime":2054.36,"body":"heating of Earth's atmosphere"},{"speaker":"on Cosmic Vision","startTime":2054.4,"endTime":2058.84,"body":"risks pushing you into this vicious cycle."},{"speaker":"on Cosmic Vision","startTime":2058.84,"endTime":2063.16,"body":"Too much CO2 could contribute to that."},{"speaker":"on Cosmic Vision","startTime":2063.16,"endTime":2064.333,"body":"More of that later."},{"speaker":"on Cosmic Vision","startTime":2065.23,"endTime":2067.81,"body":"Now, let's think about negative feedback."},{"speaker":"on Cosmic Vision","startTime":2067.81,"endTime":2069.85,"body":"Is negative feedback a good thing?"},{"speaker":"on Cosmic Vision","startTime":2069.85,"endTime":2073.33,"body":"Normally negative things"},{"speaker":"on Cosmic Vision","startTime":2069.85,"endTime":2073.33,"body":"are things we want to avoid."},{"speaker":"on Cosmic Vision","startTime":2073.33,"endTime":2075.85,"body":"Is negative feedback a good thing?"},{"speaker":"on Cosmic Vision","startTime":2075.85,"endTime":2079.9,"body":"It really is. Negative"},{"speaker":"on Cosmic Vision","startTime":2075.85,"endTime":2079.9,"body":"feedback is about regulating."},{"speaker":"on Cosmic Vision","startTime":2079.9,"endTime":2084.9,"body":"So a simple example of this"},{"speaker":"on Cosmic Vision","startTime":2079.9,"endTime":2084.9,"body":"is the thermostat in a room."},{"speaker":"on Cosmic Vision","startTime":2084.91,"endTime":2088.93,"body":"When a room gets cool, if"},{"speaker":"on Cosmic Vision","startTime":2084.91,"endTime":2088.93,"body":"you've got a working thermostat,"},{"speaker":"on Cosmic Vision","startTime":2088.93,"endTime":2091.39,"body":"the thermostat will then"},{"speaker":"on Cosmic Vision","startTime":2088.93,"endTime":2091.39,"body":"turn the heating on,"},{"speaker":"on Cosmic Vision","startTime":2091.39,"endTime":2093.97,"body":"so the room will warm up."},{"speaker":"on Cosmic Vision","startTime":2093.97,"endTime":2096.46,"body":"Then, when it gets to the"},{"speaker":"on Cosmic Vision","startTime":2093.97,"endTime":2096.46,"body":"temperature it's been set to,"},{"speaker":"on Cosmic Vision","startTime":2096.46,"endTime":2098.44,"body":"the heating will turn off,"},{"speaker":"on Cosmic Vision","startTime":2098.44,"endTime":2101.35,"body":"so gradually the room"},{"speaker":"on Cosmic Vision","startTime":2098.44,"endTime":2101.35,"body":"will start to cool again,"},{"speaker":"on Cosmic Vision","startTime":2101.35,"endTime":2102.19,"body":"and then, after a while,"},{"speaker":"on Cosmic Vision","startTime":2102.19,"endTime":2105.64,"body":"the thermostat will turn"},{"speaker":"on Cosmic Vision","startTime":2102.19,"endTime":2105.64,"body":"the heating on for a bit,"},{"speaker":"on Cosmic Vision","startTime":2105.64,"endTime":2107.86,"body":"the room will get hot,"},{"speaker":"on Cosmic Vision","startTime":2107.86,"endTime":2110.8,"body":"and then, after a while,"},{"speaker":"on Cosmic Vision","startTime":2107.86,"endTime":2110.8,"body":"the thermostat will turn off"},{"speaker":"on Cosmic Vision","startTime":2110.8,"endTime":2111.85,"body":"and the room will cool again."},{"speaker":"on Cosmic Vision","startTime":2111.85,"endTime":2113.53,"body":"That's negative feedback,"},{"speaker":"on Cosmic Vision","startTime":2113.53,"endTime":2116.59,"body":"when you regulate the important property,"},{"speaker":"on Cosmic Vision","startTime":2116.59,"endTime":2117.973,"body":"in this case, temperature."},{"speaker":"on Cosmic Vision","startTime":2119.47,"endTime":2123.22,"body":"Unfortunately, there's no"},{"speaker":"on Cosmic Vision","startTime":2119.47,"endTime":2123.22,"body":"thermostat that we know of"},{"speaker":"on Cosmic Vision","startTime":2123.22,"endTime":2125.203,"body":"in planetary atmospheres."},{"speaker":"on Cosmic Vision","startTime":2126.31,"endTime":2129.43,"body":"Positive and negative feedback,"},{"speaker":"on Cosmic Vision","startTime":2129.43,"endTime":2133.81,"body":"positive feedback processes and"},{"speaker":"on Cosmic Vision","startTime":2129.43,"endTime":2133.81,"body":"negative feedback processes,"},{"speaker":"on Cosmic Vision","startTime":2133.81,"endTime":2138.01,"body":"are a thing in biology,"},{"speaker":"on Cosmic Vision","startTime":2133.81,"endTime":2138.01,"body":"in system engineering,"},{"speaker":"on Cosmic Vision","startTime":2138.01,"endTime":2141.88,"body":"in chemistry, in economics."},{"speaker":"on Cosmic Vision","startTime":2141.88,"endTime":2142.821,"body":"Hmm."},{"speaker":"on Cosmic Vision","startTime":2142.821,"endTime":2144.7,"body":"(audience laughs)"},{"speaker":"on Cosmic Vision","startTime":2144.7,"endTime":2148.0,"body":"Let's stay focused on"},{"speaker":"on Cosmic Vision","startTime":2144.7,"endTime":2148.0,"body":"Earth's atmosphere, shall we?"},{"speaker":"on Cosmic Vision","startTime":2148.0,"endTime":2151.99,"body":"It's highly relevant"},{"speaker":"on Cosmic Vision","startTime":2148.0,"endTime":2151.99,"body":"to atmospheric physics"},{"speaker":"on Cosmic Vision","startTime":2151.99,"endTime":2156.13,"body":"and to the evolution of"},{"speaker":"on Cosmic Vision","startTime":2151.99,"endTime":2156.13,"body":"planetary atmospheres."},{"speaker":"on Cosmic Vision","startTime":2156.13,"endTime":2159.67,"body":"Now, a specific type of positive feedback"},{"speaker":"on Cosmic Vision","startTime":2159.67,"endTime":2161.863,"body":"is that of the greenhouse effect."},{"speaker":"on Cosmic Vision","startTime":2162.76,"endTime":2164.86,"body":"What is the greenhouse effect?"},{"speaker":"on Cosmic Vision","startTime":2164.86,"endTime":2168.55,"body":"And surely greenhouse is"},{"speaker":"on Cosmic Vision","startTime":2164.86,"endTime":2168.55,"body":"a really positive thing."},{"speaker":"on Cosmic Vision","startTime":2168.55,"endTime":2172.0,"body":"Why yes, but context is everything."},{"speaker":"on Cosmic Vision","startTime":2172.0,"endTime":2174.31,"body":"The greenhouse effect is a wonderful thing"},{"speaker":"on Cosmic Vision","startTime":2174.31,"endTime":2176.89,"body":"in the context of growing tomatoes."},{"speaker":"on Cosmic Vision","startTime":2176.89,"endTime":2178.33,"body":"This is my dad's greenhouse,"},{"speaker":"on Cosmic Vision","startTime":2178.33,"endTime":2182.68,"body":"and he grows the best"},{"speaker":"on Cosmic Vision","startTime":2178.33,"endTime":2182.68,"body":"tomatoes in the universe."},{"speaker":"on Cosmic Vision","startTime":2182.68,"endTime":2185.44,"body":"So, why am I associating"},{"speaker":"on Cosmic Vision","startTime":2182.68,"endTime":2185.44,"body":"the greenhouse effect"},{"speaker":"on Cosmic Vision","startTime":2185.44,"endTime":2186.88,"body":"with positive feedback,"},{"speaker":"on Cosmic Vision","startTime":2186.88,"endTime":2189.373,"body":"which we've just said is something bad?"},{"speaker":"on Cosmic Vision","startTime":2190.57,"endTime":2192.91,"body":"Context is everything."},{"speaker":"on Cosmic Vision","startTime":2192.91,"endTime":2197.91,"body":"The glass of a greenhouse can"},{"speaker":"on Cosmic Vision","startTime":2192.91,"endTime":2197.91,"body":"contain and trap heat energy."},{"speaker":"on Cosmic Vision","startTime":2199.27,"endTime":2202.0,"body":"When sunlight comes in during the day,"},{"speaker":"on Cosmic Vision","startTime":2202.0,"endTime":2203.25,"body":"it predominantly comes in"},{"speaker":"on Cosmic Vision","startTime":2203.25,"endTime":2206.71,"body":"in the form of UV light and optical light,"},{"speaker":"on Cosmic Vision","startTime":2206.71,"endTime":2208.15,"body":"which heats the surroundings,"},{"speaker":"on Cosmic Vision","startTime":2208.15,"endTime":2210.13,"body":"heats the sand the"},{"speaker":"on Cosmic Vision","startTime":2208.15,"endTime":2210.13,"body":"tomatoes are growing in,"},{"speaker":"on Cosmic Vision","startTime":2210.13,"endTime":2211.27,"body":"heats the tomatoes."},{"speaker":"on Cosmic Vision","startTime":2211.27,"endTime":2214.36,"body":"They grow bigger and more delicious."},{"speaker":"on Cosmic Vision","startTime":2214.36,"endTime":2218.62,"body":"And then, that heat"},{"speaker":"on Cosmic Vision","startTime":2214.36,"endTime":2218.62,"body":"energy wants to reradiate"},{"speaker":"on Cosmic Vision","startTime":2218.62,"endTime":2221.32,"body":"as infrared photons."},{"speaker":"on Cosmic Vision","startTime":2221.32,"endTime":2224.38,"body":"But glass isn't transparent"},{"speaker":"on Cosmic Vision","startTime":2221.32,"endTime":2224.38,"body":"to infrared photons."},{"speaker":"on Cosmic Vision","startTime":2224.38,"endTime":2227.89,"body":"They get trapped, and"},{"speaker":"on Cosmic Vision","startTime":2224.38,"endTime":2227.89,"body":"they maintain the heat,"},{"speaker":"on Cosmic Vision","startTime":2227.89,"endTime":2231.64,"body":"and that's tremendous"},{"speaker":"on Cosmic Vision","startTime":2227.89,"endTime":2231.64,"body":"for growing tomatoes."},{"speaker":"on Cosmic Vision","startTime":2231.64,"endTime":2233.02,"body":"But if you've got something called"},{"speaker":"on Cosmic Vision","startTime":2233.02,"endTime":2235.36,"body":"a runaway greenhouse effect,"},{"speaker":"on Cosmic Vision","startTime":2235.36,"endTime":2238.42,"body":"and that's not a cutesy"},{"speaker":"on Cosmic Vision","startTime":2235.36,"endTime":2238.42,"body":"cartoon thing, by the way."},{"speaker":"on Cosmic Vision","startTime":2238.42,"endTime":2240.4,"body":"That's when the greenhouse effect"},{"speaker":"on Cosmic Vision","startTime":2240.4,"endTime":2243.13,"body":"has turned into a vicious cycle."},{"speaker":"on Cosmic Vision","startTime":2243.13,"endTime":2245.26,"body":"That's when you've got problems."},{"speaker":"on Cosmic Vision","startTime":2245.26,"endTime":2247.33,"body":"And this term, the greenhouse effect,"},{"speaker":"on Cosmic Vision","startTime":2247.33,"endTime":2250.9,"body":"is used in the context"},{"speaker":"on Cosmic Vision","startTime":2247.33,"endTime":2250.9,"body":"of planetary atmospheres."},{"speaker":"on Cosmic Vision","startTime":2250.9,"endTime":2254.44,"body":"It's been hypothesized"},{"speaker":"on Cosmic Vision","startTime":2250.9,"endTime":2254.44,"body":"in the case of Venus."},{"speaker":"on Cosmic Vision","startTime":2254.44,"endTime":2257.71,"body":"A runaway greenhouse effect occurs"},{"speaker":"on Cosmic Vision","startTime":2257.71,"endTime":2261.37,"body":"when a planet absorbs"},{"speaker":"on Cosmic Vision","startTime":2257.71,"endTime":2261.37,"body":"more energy from the Sun"},{"speaker":"on Cosmic Vision","startTime":2261.37,"endTime":2265.183,"body":"than it can then"},{"speaker":"on Cosmic Vision","startTime":2261.37,"endTime":2265.183,"body":"reradiate back into space."},{"speaker":"on Cosmic Vision","startTime":2266.32,"endTime":2268.9,"body":"Sunlight can warm the ground,"},{"speaker":"on Cosmic Vision","startTime":2268.9,"endTime":2271.12,"body":"Earth's surface during the day,"},{"speaker":"on Cosmic Vision","startTime":2271.12,"endTime":2274.63,"body":"and then, at night, the"},{"speaker":"on Cosmic Vision","startTime":2271.12,"endTime":2274.63,"body":"energy should radiate"},{"speaker":"on Cosmic Vision","startTime":2274.63,"endTime":2279.28,"body":"back into space in the"},{"speaker":"on Cosmic Vision","startTime":2274.63,"endTime":2279.28,"body":"form of infrared rays,"},{"speaker":"on Cosmic Vision","startTime":2279.28,"endTime":2281.143,"body":"and it should cool down."},{"speaker":"on Cosmic Vision","startTime":2282.01,"endTime":2284.17,"body":"But what could trap the heat"},{"speaker":"on Cosmic Vision","startTime":2284.17,"endTime":2286.48,"body":"in the context of Earth's atmosphere?"},{"speaker":"on Cosmic Vision","startTime":2286.48,"endTime":2291.04,"body":"There's no glass there like"},{"speaker":"on Cosmic Vision","startTime":2286.48,"endTime":2291.04,"body":"there is in a greenhouse."},{"speaker":"on Cosmic Vision","startTime":2291.04,"endTime":2293.293,"body":"What is it that could"},{"speaker":"on Cosmic Vision","startTime":2291.04,"endTime":2293.293,"body":"be trapping the heat?"},{"speaker":"on Cosmic Vision","startTime":2294.37,"endTime":2298.12,"body":"Well, if your atmosphere"},{"speaker":"on Cosmic Vision","startTime":2294.37,"endTime":2298.12,"body":"consisted entirely"},{"speaker":"on Cosmic Vision","startTime":2298.12,"endTime":2300.22,"body":"of homonuclear molecules,"},{"speaker":"on Cosmic Vision","startTime":2300.22,"endTime":2303.82,"body":"that is a molecule which"},{"speaker":"on Cosmic Vision","startTime":2300.22,"endTime":2303.82,"body":"comprises more than one atom,"},{"speaker":"on Cosmic Vision","startTime":2303.82,"endTime":2305.59,"body":"obviously, 'cause it's a molecule,"},{"speaker":"on Cosmic Vision","startTime":2305.59,"endTime":2308.05,"body":"but the same sort of atom,"},{"speaker":"on Cosmic Vision","startTime":2308.05,"endTime":2311.503,"body":"that actually wouldn't"},{"speaker":"on Cosmic Vision","startTime":2308.05,"endTime":2311.503,"body":"contribute to trapping the heat."},{"speaker":"on Cosmic Vision","startTime":2312.37,"endTime":2317.37,"body":"So, if our atmosphere"},{"speaker":"on Cosmic Vision","startTime":2312.37,"endTime":2317.37,"body":"consisted solely of nitrogen"},{"speaker":"on Cosmic Vision","startTime":2317.5,"endTime":2321.88,"body":"in the form of N2 and"},{"speaker":"on Cosmic Vision","startTime":2317.5,"endTime":2321.88,"body":"oxygen in the form of O2,"},{"speaker":"on Cosmic Vision","startTime":2321.88,"endTime":2325.483,"body":"we wouldn't be having a greenhouse effect."},{"speaker":"on Cosmic Vision","startTime":2326.56,"endTime":2329.68,"body":"And that's because in"},{"speaker":"on Cosmic Vision","startTime":2326.56,"endTime":2329.68,"body":"a homonuclear molecule,"},{"speaker":"on Cosmic Vision","startTime":2329.68,"endTime":2331.84,"body":"where you've got an oxygen atom here"},{"speaker":"on Cosmic Vision","startTime":2331.84,"endTime":2334.18,"body":"and an oxygen atom here,"},{"speaker":"on Cosmic Vision","startTime":2334.18,"endTime":2336.61,"body":"this is a completely symmetric situation"},{"speaker":"on Cosmic Vision","startTime":2336.61,"endTime":2338.92,"body":"between the two atoms."},{"speaker":"on Cosmic Vision","startTime":2338.92,"endTime":2342.16,"body":"The nucleus of the oxygen here"},{"speaker":"on Cosmic Vision","startTime":2342.16,"endTime":2344.26,"body":"and the nucleus of the oxygen here"},{"speaker":"on Cosmic Vision","startTime":2344.26,"endTime":2347.53,"body":"will be equally attractive"},{"speaker":"on Cosmic Vision","startTime":2344.26,"endTime":2347.53,"body":"to the cloud of electrons"},{"speaker":"on Cosmic Vision","startTime":2347.53,"endTime":2349.81,"body":"associated with that molecule"},{"speaker":"on Cosmic Vision","startTime":2349.81,"endTime":2352.693,"body":"and orbiting around the two oxygens."},{"speaker":"on Cosmic Vision","startTime":2353.62,"endTime":2357.25,"body":"So you don't have any"},{"speaker":"on Cosmic Vision","startTime":2353.62,"endTime":2357.25,"body":"separation of charge."},{"speaker":"on Cosmic Vision","startTime":2357.25,"endTime":2359.56,"body":"A separation of charge is something"},{"speaker":"on Cosmic Vision","startTime":2359.56,"endTime":2362.56,"body":"that we refer to as a dipole moment."},{"speaker":"on Cosmic Vision","startTime":2362.56,"endTime":2364.27,"body":"Don't worry if you're not"},{"speaker":"on Cosmic Vision","startTime":2362.56,"endTime":2364.27,"body":"familiar with that term."},{"speaker":"on Cosmic Vision","startTime":2364.27,"endTime":2367.87,"body":"It just means we've got a"},{"speaker":"on Cosmic Vision","startTime":2364.27,"endTime":2367.87,"body":"net separation of charge,"},{"speaker":"on Cosmic Vision","startTime":2367.87,"endTime":2370.99,"body":"a net electric field."},{"speaker":"on Cosmic Vision","startTime":2370.99,"endTime":2374.71,"body":"So you don't have that in the"},{"speaker":"on Cosmic Vision","startTime":2370.99,"endTime":2374.71,"body":"case of homonuclear molecules"},{"speaker":"on Cosmic Vision","startTime":2374.71,"endTime":2375.787,"body":"like N2 and O2."},{"speaker":"on Cosmic Vision","startTime":2378.3,"endTime":2383.08,"body":"In such a case, the atmosphere"},{"speaker":"on Cosmic Vision","startTime":2378.3,"endTime":2383.08,"body":"is approximately transparent."},{"speaker":"on Cosmic Vision","startTime":2383.08,"endTime":2387.43,"body":"Light does not couple to"},{"speaker":"on Cosmic Vision","startTime":2383.08,"endTime":2387.43,"body":"homonuclear molecules."},{"speaker":"on Cosmic Vision","startTime":2387.43,"endTime":2389.65,"body":"Light gets in and out."},{"speaker":"on Cosmic Vision","startTime":2389.65,"endTime":2393.4,"body":"It does not trap the infrared photons,"},{"speaker":"on Cosmic Vision","startTime":2393.4,"endTime":2397.72,"body":"and it's perfectly permeable,"},{"speaker":"on Cosmic Vision","startTime":2393.4,"endTime":2397.72,"body":"perfectly transparent"},{"speaker":"on Cosmic Vision","startTime":2397.72,"endTime":2402.72,"body":"to optical ultraviolet photons"},{"speaker":"on Cosmic Vision","startTime":2397.72,"endTime":2402.72,"body":"as well as infrared photons."},{"speaker":"on Cosmic Vision","startTime":2403.75,"endTime":2407.05,"body":"But what about heteronuclear molecules?"},{"speaker":"on Cosmic Vision","startTime":2407.05,"endTime":2410.74,"body":"Molecules like CO2,"},{"speaker":"on Cosmic Vision","startTime":2410.74,"endTime":2413.593,"body":"where you've got different"},{"speaker":"on Cosmic Vision","startTime":2410.74,"endTime":2413.593,"body":"species within one molecule."},{"speaker":"on Cosmic Vision","startTime":2414.43,"endTime":2415.63,"body":"Well, let's remind ourselves"},{"speaker":"on Cosmic Vision","startTime":2415.63,"endTime":2419.23,"body":"what a light ray is, what a photon is."},{"speaker":"on Cosmic Vision","startTime":2419.23,"endTime":2422.74,"body":"A light ray is where you"},{"speaker":"on Cosmic Vision","startTime":2419.23,"endTime":2422.74,"body":"have varying electric"},{"speaker":"on Cosmic Vision","startTime":2422.74,"endTime":2426.04,"body":"and magnetic fields."},{"speaker":"on Cosmic Vision","startTime":2426.04,"endTime":2427.78,"body":"This is something that I discussed"},{"speaker":"on Cosmic Vision","startTime":2427.78,"endTime":2430.06,"body":"in my very first Gresham lecture"},{"speaker":"on Cosmic Vision","startTime":2430.06,"endTime":2433.033,"body":"in a lecture entitled Faster than Light?"},{"speaker":"on Cosmic Vision","startTime":2434.92,"endTime":2438.55,"body":"So, why might light in"},{"speaker":"on Cosmic Vision","startTime":2434.92,"endTime":2438.55,"body":"the form of these electric"},{"speaker":"on Cosmic Vision","startTime":2438.55,"endTime":2442.21,"body":"and magnetic packets of energy,"},{"speaker":"on Cosmic Vision","startTime":2442.21,"endTime":2445.663,"body":"why might they couple to"},{"speaker":"on Cosmic Vision","startTime":2442.21,"endTime":2445.663,"body":"heteronuclear molecules?"},{"speaker":"on Cosmic Vision","startTime":2446.77,"endTime":2450.88,"body":"Why might sunlight couple"},{"speaker":"on Cosmic Vision","startTime":2446.77,"endTime":2450.88,"body":"to heteronuclear molecules?"},{"speaker":"on Cosmic Vision","startTime":2450.88,"endTime":2453.49,"body":"Well, let's just imagine"},{"speaker":"on Cosmic Vision","startTime":2450.88,"endTime":2453.49,"body":"this little symbol here"},{"speaker":"on Cosmic Vision","startTime":2453.49,"endTime":2458.49,"body":"represents the heteronuclear"},{"speaker":"on Cosmic Vision","startTime":2453.49,"endTime":2458.49,"body":"molecule of H2O."},{"speaker":"on Cosmic Vision","startTime":2459.79,"endTime":2462.67,"body":"The charge on the nucleus"},{"speaker":"on Cosmic Vision","startTime":2459.79,"endTime":2462.67,"body":"of the different atoms"},{"speaker":"on Cosmic Vision","startTime":2462.67,"endTime":2465.97,"body":"in this particular molecule"},{"speaker":"on Cosmic Vision","startTime":2462.67,"endTime":2465.97,"body":"is going to be different"},{"speaker":"on Cosmic Vision","startTime":2465.97,"endTime":2469.423,"body":"for the different types of nucleus."},{"speaker":"on Cosmic Vision","startTime":2470.26,"endTime":2473.41,"body":"The hydrogen nucleus"},{"speaker":"on Cosmic Vision","startTime":2470.26,"endTime":2473.41,"body":"only contains one proton."},{"speaker":"on Cosmic Vision","startTime":2473.41,"endTime":2476.2,"body":"It has a positive charge of plus one."},{"speaker":"on Cosmic Vision","startTime":2476.2,"endTime":2480.34,"body":"Whereas, the oxygen nucleus"},{"speaker":"on Cosmic Vision","startTime":2476.2,"endTime":2480.34,"body":"has a charge of plus eight"},{"speaker":"on Cosmic Vision","startTime":2480.34,"endTime":2482.74,"body":"because it's got eight protons."},{"speaker":"on Cosmic Vision","startTime":2482.74,"endTime":2485.71,"body":"So the electrons associated originally"},{"speaker":"on Cosmic Vision","startTime":2485.71,"endTime":2488.41,"body":"with the oxygen and the hydrogen,"},{"speaker":"on Cosmic Vision","startTime":2488.41,"endTime":2490.12,"body":"while they're going to be whizzing around"},{"speaker":"on Cosmic Vision","startTime":2490.12,"endTime":2491.02,"body":"within that molecule,"},{"speaker":"on Cosmic Vision","startTime":2491.02,"endTime":2493.66,"body":"they're going to be"},{"speaker":"on Cosmic Vision","startTime":2491.02,"endTime":2493.66,"body":"preferentially more drawn"},{"speaker":"on Cosmic Vision","startTime":2493.66,"endTime":2496.69,"body":"to the more positively charged oxygen."},{"speaker":"on Cosmic Vision","startTime":2496.69,"endTime":2500.08,"body":"Hence, you have a little"},{"speaker":"on Cosmic Vision","startTime":2496.69,"endTime":2500.08,"body":"bit of an electric field"},{"speaker":"on Cosmic Vision","startTime":2500.08,"endTime":2504.433,"body":"between the O and the two Hs."},{"speaker":"on Cosmic Vision","startTime":2505.42,"endTime":2509.74,"body":"Entirely similarly with CO2,"},{"speaker":"on Cosmic Vision","startTime":2509.74,"endTime":2512.8,"body":"the carbon nucleus has a"},{"speaker":"on Cosmic Vision","startTime":2509.74,"endTime":2512.8,"body":"positive charge of plus six"},{"speaker":"on Cosmic Vision","startTime":2512.8,"endTime":2515.65,"body":"and the oxygen charges are plus eight,"},{"speaker":"on Cosmic Vision","startTime":2515.65,"endTime":2517.45,"body":"on the nuclei, I mean,"},{"speaker":"on Cosmic Vision","startTime":2517.45,"endTime":2519.88,"body":"so the electrons are"},{"speaker":"on Cosmic Vision","startTime":2517.45,"endTime":2519.88,"body":"going to be preferentially"},{"speaker":"on Cosmic Vision","startTime":2519.88,"endTime":2523.12,"body":"drawn towards the more positive charge."},{"speaker":"on Cosmic Vision","startTime":2523.12,"endTime":2525.49,"body":"So there's going to be"},{"speaker":"on Cosmic Vision","startTime":2523.12,"endTime":2525.49,"body":"a slight dipole moment,"},{"speaker":"on Cosmic Vision","startTime":2525.49,"endTime":2528.52,"body":"a slight, because there's"},{"speaker":"on Cosmic Vision","startTime":2525.49,"endTime":2528.52,"body":"a separation of charge,"},{"speaker":"on Cosmic Vision","startTime":2528.52,"endTime":2530.833,"body":"there's going to be a"},{"speaker":"on Cosmic Vision","startTime":2528.52,"endTime":2530.833,"body":"slight electric field,"},{"speaker":"on Cosmic Vision","startTime":2531.85,"endTime":2535.24,"body":"and that's why light rays, photons,"},{"speaker":"on Cosmic Vision","startTime":2535.24,"endTime":2538.03,"body":"those waves of electric"},{"speaker":"on Cosmic Vision","startTime":2535.24,"endTime":2538.03,"body":"field and magnetic field,"},{"speaker":"on Cosmic Vision","startTime":2538.03,"endTime":2542.56,"body":"can couple to them and impart"},{"speaker":"on Cosmic Vision","startTime":2538.03,"endTime":2542.56,"body":"energy to those molecules"},{"speaker":"on Cosmic Vision","startTime":2542.56,"endTime":2545.47,"body":"so that you can then store"},{"speaker":"on Cosmic Vision","startTime":2542.56,"endTime":2545.47,"body":"energy within the bonds"},{"speaker":"on Cosmic Vision","startTime":2545.47,"endTime":2549.013,"body":"between the C and the"},{"speaker":"on Cosmic Vision","startTime":2545.47,"endTime":2549.013,"body":"O and the H and the O."},{"speaker":"on Cosmic Vision","startTime":2549.85,"endTime":2551.89,"body":"This is another reason"},{"speaker":"on Cosmic Vision","startTime":2549.85,"endTime":2551.89,"body":"why we can't even see"},{"speaker":"on Cosmic Vision","startTime":2551.89,"endTime":2553.45,"body":"the surface of Venus."},{"speaker":"on Cosmic Vision","startTime":2553.45,"endTime":2556.06,"body":"It's because it's full of CO2,"},{"speaker":"on Cosmic Vision","startTime":2556.06,"endTime":2558.47,"body":"and light is not transparent"},{"speaker":"on Cosmic Vision","startTime":2559.48,"endTime":2563.98,"body":"in situations where it"},{"speaker":"on Cosmic Vision","startTime":2559.48,"endTime":2563.98,"body":"couples to the molecules,"},{"speaker":"on Cosmic Vision","startTime":2563.98,"endTime":2568.03,"body":"which is all the time if you've"},{"speaker":"on Cosmic Vision","startTime":2563.98,"endTime":2568.03,"body":"got heteronuclear molecules."},{"speaker":"on Cosmic Vision","startTime":2568.03,"endTime":2572.41,"body":"As I said, the atmosphere"},{"speaker":"on Cosmic Vision","startTime":2568.03,"endTime":2572.41,"body":"of Venus is 96% CO2,"},{"speaker":"on Cosmic Vision","startTime":2572.41,"endTime":2576.58,"body":"and that's why we can't see the"},{"speaker":"on Cosmic Vision","startTime":2572.41,"endTime":2576.58,"body":"surface of Venus from Earth."},{"speaker":"on Cosmic Vision","startTime":2576.58,"endTime":2578.35,"body":"The only way we can see the surface"},{"speaker":"on Cosmic Vision","startTime":2578.35,"endTime":2583.15,"body":"is if we actually land an"},{"speaker":"on Cosmic Vision","startTime":2578.35,"endTime":2583.15,"body":"explorer on the surface of Venus,"},{"speaker":"on Cosmic Vision","startTime":2583.15,"endTime":2585.58,"body":"which has been done at"},{"speaker":"on Cosmic Vision","startTime":2583.15,"endTime":2585.58,"body":"some times in the past,"},{"speaker":"on Cosmic Vision","startTime":2585.58,"endTime":2589.63,"body":"which is how we know about"},{"speaker":"on Cosmic Vision","startTime":2585.58,"endTime":2589.63,"body":"its chemical constituents,"},{"speaker":"on Cosmic Vision","startTime":2589.63,"endTime":2591.943,"body":"its pressure and its temperature."},{"speaker":"on Cosmic Vision","startTime":2593.08,"endTime":2596.53,"body":"So Venus' atmosphere is"},{"speaker":"on Cosmic Vision","startTime":2593.08,"endTime":2596.53,"body":"not transparent to light"},{"speaker":"on Cosmic Vision","startTime":2596.53,"endTime":2599.23,"body":"because that light is absorbed by the CO2"},{"speaker":"on Cosmic Vision","startTime":2599.23,"endTime":2603.58,"body":"and imparts energy to"},{"speaker":"on Cosmic Vision","startTime":2599.23,"endTime":2603.58,"body":"the CO2, heating it up,"},{"speaker":"on Cosmic Vision","startTime":2603.58,"endTime":2607.093,"body":"contributing to that vicious"},{"speaker":"on Cosmic Vision","startTime":2603.58,"endTime":2607.093,"body":"cycle that I mentioned."},{"speaker":"on Cosmic Vision","startTime":2609.1,"endTime":2610.6,"body":"Incidentally, the converse of this"},{"speaker":"on Cosmic Vision","startTime":2610.6,"endTime":2613.03,"body":"is why we can easily see"},{"speaker":"on Cosmic Vision","startTime":2610.6,"endTime":2613.03,"body":"the surface of the Moon."},{"speaker":"on Cosmic Vision","startTime":2613.03,"endTime":2614.89,"body":"Doesn't have an atmosphere at all."},{"speaker":"on Cosmic Vision","startTime":2614.89,"endTime":2617.92,"body":"No heteronuclear molecules,"},{"speaker":"on Cosmic Vision","startTime":2614.89,"endTime":2617.92,"body":"no homonuclear molecules."},{"speaker":"on Cosmic Vision","startTime":2617.92,"endTime":2620.59,"body":"We can always see the surface of the Moon"},{"speaker":"on Cosmic Vision","startTime":2620.59,"endTime":2623.312,"body":"as long as there are no clouds of H2O,"},{"speaker":"on Cosmic Vision","startTime":2623.312,"endTime":2627.703,"body":"which is water droplets"},{"speaker":"on Cosmic Vision","startTime":2623.312,"endTime":2627.703,"body":"in the case of Earth."},{"speaker":"on Cosmic Vision","startTime":2629.2,"endTime":2632.653,"body":"So what I've been describing,"},{"speaker":"on Cosmic Vision","startTime":2629.2,"endTime":2632.653,"body":"the greenhouse effect,"},{"speaker":"on Cosmic Vision","startTime":2633.97,"endTime":2638.11,"body":"has its origins in ideas first put forward"},{"speaker":"on Cosmic Vision","startTime":2638.11,"endTime":2641.8,"body":"by the French physicist"},{"speaker":"on Cosmic Vision","startTime":2638.11,"endTime":2641.8,"body":"and mathematician Fourier."},{"speaker":"on Cosmic Vision","startTime":2641.8,"endTime":2645.64,"body":"Fourier figured out the"},{"speaker":"on Cosmic Vision","startTime":2641.8,"endTime":2645.64,"body":"relevant physics of atmospheres"},{"speaker":"on Cosmic Vision","startTime":2645.64,"endTime":2649.81,"body":"that we now know in terms of"},{"speaker":"on Cosmic Vision","startTime":2645.64,"endTime":2649.81,"body":"this positive feedback effect"},{"speaker":"on Cosmic Vision","startTime":2649.81,"endTime":2652.39,"body":"called the greenhouse effect."},{"speaker":"on Cosmic Vision","startTime":2652.39,"endTime":2654.13,"body":"Fourier is a really good guy."},{"speaker":"on Cosmic Vision","startTime":2654.13,"endTime":2657.37,"body":"Not only did he figure"},{"speaker":"on Cosmic Vision","startTime":2654.13,"endTime":2657.37,"body":"out that important part"},{"speaker":"on Cosmic Vision","startTime":2657.37,"endTime":2659.38,"body":"of atmospheric physics"},{"speaker":"on Cosmic Vision","startTime":2659.38,"endTime":2663.94,"body":"and other important"},{"speaker":"on Cosmic Vision","startTime":2659.38,"endTime":2663.94,"body":"aspects of thermodynamics,"},{"speaker":"on Cosmic Vision","startTime":2663.94,"endTime":2666.76,"body":"he also developed the mathematical tools"},{"speaker":"on Cosmic Vision","startTime":2666.76,"endTime":2671.76,"body":"which are widely used today"},{"speaker":"on Cosmic Vision","startTime":2666.76,"endTime":2671.76,"body":"in CT scans and MRI scans,"},{"speaker":"on Cosmic Vision","startTime":2671.77,"endTime":2675.55,"body":"and, indeed, for important"},{"speaker":"on Cosmic Vision","startTime":2671.77,"endTime":2675.55,"body":"parts of astronomy,"},{"speaker":"on Cosmic Vision","startTime":2675.55,"endTime":2677.38,"body":"such as interferometry,"},{"speaker":"on Cosmic Vision","startTime":2677.38,"endTime":2682.38,"body":"which means that we get beautiful"},{"speaker":"on Cosmic Vision","startTime":2677.38,"endTime":2682.38,"body":"images of the radio sky,"},{"speaker":"on Cosmic Vision","startTime":2682.78,"endTime":2687.7,"body":"as I described in my lecture"},{"speaker":"on Cosmic Vision","startTime":2682.78,"endTime":2687.7,"body":"a year and a half ago,"},{"speaker":"Cosmic Vision","startTime":2687.7,"endTime":2690.433,"body":"Watching the Radio."},{"speaker":"Cosmic Vision","startTime":2691.57,"endTime":2694.63,"body":"So this is Fourier's original paper,"},{"speaker":"Cosmic Vision","startTime":2694.63,"endTime":2697.09,"body":"where he takes the reader through"},{"speaker":"Cosmic Vision","startTime":2697.09,"endTime":2701.383,"body":"all the different key"},{"speaker":"Cosmic Vision","startTime":2697.09,"endTime":2701.383,"body":"bits of relevant physics."},{"speaker":"Cosmic Vision","startTime":2702.43,"endTime":2706.03,"body":"The greenhouse effect does"},{"speaker":"Cosmic Vision","startTime":2702.43,"endTime":2706.03,"body":"appear to be manifesting itself"},{"speaker":"Cosmic Vision","startTime":2706.03,"endTime":2708.97,"body":"in the atmosphere of planet Earth"},{"speaker":"Cosmic Vision","startTime":2708.97,"endTime":2713.71,"body":"and causing global warming"},{"speaker":"Cosmic Vision","startTime":2708.97,"endTime":2713.71,"body":"and a changing climate,"},{"speaker":"Cosmic Vision","startTime":2713.71,"endTime":2718.71,"body":"whose behavior gives rise to"},{"speaker":"Cosmic Vision","startTime":2713.71,"endTime":2718.71,"body":"more and more extreme events."},{"speaker":"Cosmic Vision","startTime":2719.44,"endTime":2722.08,"body":"This is how the temperatures have changed"},{"speaker":"Cosmic Vision","startTime":2722.08,"endTime":2724.99,"body":"in the last 150 or so years."},{"speaker":"Cosmic Vision","startTime":2724.99,"endTime":2727.87,"body":"This is data supplied by NASA,"},{"speaker":"Cosmic Vision","startTime":2727.87,"endTime":2732.87,"body":"same people who did so"},{"speaker":"Cosmic Vision","startTime":2727.87,"endTime":2732.87,"body":"much to explore space"},{"speaker":"Cosmic Vision","startTime":2733.0,"endTime":2735.4,"body":"and make careful measurements of space,"},{"speaker":"Cosmic Vision","startTime":2735.4,"endTime":2737.89,"body":"and the brilliant engineers"},{"speaker":"Cosmic Vision","startTime":2737.89,"endTime":2740.77,"body":"who devised this measuring equipment,"},{"speaker":"Cosmic Vision","startTime":2740.77,"endTime":2743.8,"body":"who devised the actuators"},{"speaker":"Cosmic Vision","startTime":2740.77,"endTime":2743.8,"body":"that work so brilliantly"},{"speaker":"Cosmic Vision","startTime":2743.8,"endTime":2746.62,"body":"on the JWST today."},{"speaker":"Cosmic Vision","startTime":2746.62,"endTime":2748.99,"body":"These measurements of"},{"speaker":"Cosmic Vision","startTime":2746.62,"endTime":2748.99,"body":"the global temperatures"},{"speaker":"Cosmic Vision","startTime":2748.99,"endTime":2752.26,"body":"are not by cranks or people"},{"speaker":"Cosmic Vision","startTime":2748.99,"endTime":2752.26,"body":"who are out to mislead,"},{"speaker":"Cosmic Vision","startTime":2752.26,"endTime":2757.26,"body":"but the same skilled and"},{"speaker":"Cosmic Vision","startTime":2752.26,"endTime":2757.26,"body":"expert engineers and scientists"},{"speaker":"Cosmic Vision","startTime":2757.51,"endTime":2761.533,"body":"who can launch wonderful"},{"speaker":"Cosmic Vision","startTime":2757.51,"endTime":2761.533,"body":"telescopes at the same time."},{"speaker":"Cosmic Vision","startTime":2762.58,"endTime":2765.19,"body":"There's no doubt that the temperature"},{"speaker":"Cosmic Vision","startTime":2765.19,"endTime":2767.233,"body":"on this planet is increasing."},{"speaker":"Cosmic Vision","startTime":2768.37,"endTime":2770.77,"body":"But could it be that the reason"},{"speaker":"Cosmic Vision","startTime":2770.77,"endTime":2773.41,"body":"why the temperature on Earth is increasing"},{"speaker":"Cosmic Vision","startTime":2773.41,"endTime":2775.12,"body":"is just the Sun's fault?"},{"speaker":"Cosmic Vision","startTime":2775.12,"endTime":2778.27,"body":"I mean, perish the thought"},{"speaker":"Cosmic Vision","startTime":2775.12,"endTime":2778.27,"body":"that it's our fault."},{"speaker":"Cosmic Vision","startTime":2778.27,"endTime":2781.06,"body":"Could it be that an active Sun"},{"speaker":"Cosmic Vision","startTime":2781.06,"endTime":2784.21,"body":"is more responsible for"},{"speaker":"Cosmic Vision","startTime":2781.06,"endTime":2784.21,"body":"our warming climate?"},{"speaker":"Cosmic Vision","startTime":2784.21,"endTime":2787.12,"body":"In principle, it could be,"},{"speaker":"Cosmic Vision","startTime":2787.12,"endTime":2788.8,"body":"but that isn't the case."},{"speaker":"Cosmic Vision","startTime":2788.8,"endTime":2790.33,"body":"It's just not."},{"speaker":"Cosmic Vision","startTime":2790.33,"endTime":2795.1,"body":"The reason why the Earth's"},{"speaker":"Cosmic Vision","startTime":2790.33,"endTime":2795.1,"body":"atmosphere is getting hotter"},{"speaker":"Cosmic Vision","startTime":2795.1,"endTime":2797.5,"body":"and hence Earth's"},{"speaker":"Cosmic Vision","startTime":2795.1,"endTime":2797.5,"body":"surface is getting hotter"},{"speaker":"Cosmic Vision","startTime":2797.5,"endTime":2800.713,"body":"is because heat is trapped inside."},{"speaker":"Cosmic Vision","startTime":2801.76,"endTime":2804.58,"body":"If it were the Sun's fault"},{"speaker":"Cosmic Vision","startTime":2801.76,"endTime":2804.58,"body":"that we were getting hotter,"},{"speaker":"Cosmic Vision","startTime":2804.58,"endTime":2807.76,"body":"you would expect the temperature"},{"speaker":"Cosmic Vision","startTime":2804.58,"endTime":2807.76,"body":"in the upper atmosphere"},{"speaker":"Cosmic Vision","startTime":2807.76,"endTime":2809.5,"body":"of Earth to be getting hotter"},{"speaker":"Cosmic Vision","startTime":2809.5,"endTime":2811.66,"body":"and then for that heat to transmit"},{"speaker":"Cosmic Vision","startTime":2811.66,"endTime":2814.6,"body":"into the lower down"},{"speaker":"Cosmic Vision","startTime":2811.66,"endTime":2814.6,"body":"layers of the atmosphere"},{"speaker":"Cosmic Vision","startTime":2814.6,"endTime":2816.19,"body":"and then of Earth's surface."},{"speaker":"Cosmic Vision","startTime":2816.19,"endTime":2819.85,"body":"But that's not what's been"},{"speaker":"Cosmic Vision","startTime":2816.19,"endTime":2819.85,"body":"observed and measured."},{"speaker":"Cosmic Vision","startTime":2819.85,"endTime":2821.32,"body":"What has been observed and measured"},{"speaker":"Cosmic Vision","startTime":2821.32,"endTime":2823.99,"body":"is that the upper atmosphere is cooling,"},{"speaker":"Cosmic Vision","startTime":2823.99,"endTime":2827.77,"body":"and it's the closer in"},{"speaker":"Cosmic Vision","startTime":2823.99,"endTime":2827.77,"body":"layers that are getting hot."},{"speaker":"Cosmic Vision","startTime":2827.77,"endTime":2831.91,"body":"Heat is being trapped"},{"speaker":"Cosmic Vision","startTime":2827.77,"endTime":2831.91,"body":"inside the atmosphere"},{"speaker":"Cosmic Vision","startTime":2831.91,"endTime":2834.49,"body":"by greenhouse gases."},{"speaker":"Cosmic Vision","startTime":2834.49,"endTime":2837.82,"body":"In much the same way that we"},{"speaker":"Cosmic Vision","startTime":2834.49,"endTime":2837.82,"body":"trap heat close to our bodies"},{"speaker":"Cosmic Vision","startTime":2837.82,"endTime":2840.34,"body":"when we put on a warm winter coat,"},{"speaker":"Cosmic Vision","startTime":2840.34,"endTime":2843.193,"body":"heat doesn't escape as easily."},{"speaker":"Cosmic Vision","startTime":2844.27,"endTime":2848.26,"body":"Greenhouse gases, heteronuclear molecules,"},{"speaker":"Cosmic Vision","startTime":2848.26,"endTime":2851.26,"body":"not just CO2, but also H2O"},{"speaker":"Cosmic Vision","startTime":2851.26,"endTime":2853.81,"body":"and methane and a few other things,"},{"speaker":"Cosmic Vision","startTime":2853.81,"endTime":2857.23,"body":"these are responsible"},{"speaker":"Cosmic Vision","startTime":2853.81,"endTime":2857.23,"body":"for trapping heat energy,"},{"speaker":"Cosmic Vision","startTime":2857.23,"endTime":2858.88,"body":"originally from the Sun,"},{"speaker":"Cosmic Vision","startTime":2858.88,"endTime":2861.85,"body":"close to the Earth and heating it up."},{"speaker":"Cosmic Vision","startTime":2861.85,"endTime":2865.69,"body":"And even though the"},{"speaker":"Cosmic Vision","startTime":2861.85,"endTime":2865.69,"body":"levels are only the same"},{"speaker":"Cosmic Vision","startTime":2865.69,"endTime":2868.63,"body":"as the relative number"},{"speaker":"Cosmic Vision","startTime":2865.69,"endTime":2868.63,"body":"of caffeine molecules"},{"speaker":"Cosmic Vision","startTime":2868.63,"endTime":2870.67,"body":"that you have in a cup of coffee,"},{"speaker":"Cosmic Vision","startTime":2870.67,"endTime":2874.603,"body":"it's enough to contribute to"},{"speaker":"Cosmic Vision","startTime":2870.67,"endTime":2874.603,"body":"that positive feedback effect."},{"speaker":"Cosmic Vision","startTime":2875.62,"endTime":2878.38,"body":"Terribly sorry if I'm coming"},{"speaker":"Cosmic Vision","startTime":2875.62,"endTime":2878.38,"body":"across as a bit gloomy,"},{"speaker":"Cosmic Vision","startTime":2878.38,"endTime":2882.887,"body":"but I would like to quote"},{"speaker":"Cosmic Vision","startTime":2878.38,"endTime":2882.887,"body":"Carl Sagan, who pointed out,"},{"speaker":"Cosmic Vision","startTime":2882.887,"endTime":2886.88,"body":"\"It is far better to grasp"},{"speaker":"Cosmic Vision","startTime":2882.887,"endTime":2886.88,"body":"the Universe as it really is"},{"speaker":"Cosmic Vision","startTime":2886.88,"endTime":2889.217,"body":"\"than to persist in delusion,"},{"speaker":"Cosmic Vision","startTime":2889.217,"endTime":2892.537,"body":"\"however, satisfying and reassuring.\""},{"speaker":"Cosmic Vision","startTime":2893.74,"endTime":2896.53,"body":"This is Carl Sagan, for"},{"speaker":"Cosmic Vision","startTime":2893.74,"endTime":2896.53,"body":"those who don't know,"},{"speaker":"Cosmic Vision","startTime":2896.53,"endTime":2899.86,"body":"is the American, the"},{"speaker":"Cosmic Vision","startTime":2896.53,"endTime":2899.86,"body":"late American astronomer"},{"speaker":"Cosmic Vision","startTime":2899.86,"endTime":2901.603,"body":"and cosmologist and writer."},{"speaker":"Cosmic Vision","startTime":2903.13,"endTime":2906.64,"body":"I wonder what future"},{"speaker":"Cosmic Vision","startTime":2903.13,"endTime":2906.64,"body":"generations will say of us,"},{"speaker":"Cosmic Vision","startTime":2906.64,"endTime":2911.02,"body":"perhaps by the time King"},{"speaker":"Cosmic Vision","startTime":2906.64,"endTime":2911.02,"body":"George VII is on the throne."},{"speaker":"Cosmic Vision","startTime":2911.02,"endTime":2913.99,"body":"I think they might very"},{"speaker":"Cosmic Vision","startTime":2911.02,"endTime":2913.99,"body":"reasonably ask the question,"},{"speaker":"Cosmic Vision","startTime":2913.99,"endTime":2916.57,"body":"what on Earth did you think you were doing"},{"speaker":"Cosmic Vision","startTime":2916.57,"endTime":2920.59,"body":"using up fossil fuels,"},{"speaker":"Cosmic Vision","startTime":2916.57,"endTime":2920.59,"body":"hydrocarbons buried in the ground,"},{"speaker":"Cosmic Vision","startTime":2920.59,"endTime":2922.63,"body":"to heat up buildings?"},{"speaker":"Cosmic Vision","startTime":2922.63,"endTime":2924.25,"body":"What on Earth did you think you were doing"},{"speaker":"Cosmic Vision","startTime":2924.25,"endTime":2927.7,"body":"using fossil fuels to heat up water?"},{"speaker":"Cosmic Vision","startTime":2927.7,"endTime":2930.04,"body":"That reaction in reverse now."},{"speaker":"Cosmic Vision","startTime":2930.04,"endTime":2932.35,"body":"Hydrocarbons and oxygen,"},{"speaker":"Cosmic Vision","startTime":2932.35,"endTime":2936.04,"body":"when burnt to heat"},{"speaker":"Cosmic Vision","startTime":2932.35,"endTime":2936.04,"body":"water, to heat buildings,"},{"speaker":"Cosmic Vision","startTime":2936.04,"endTime":2939.43,"body":"gives rise to CO2, which is really bad,"},{"speaker":"Cosmic Vision","startTime":2939.43,"endTime":2941.77,"body":"even if it's an exothermic reaction,"},{"speaker":"Cosmic Vision","startTime":2941.77,"endTime":2944.923,"body":"and we get energy out of it"},{"speaker":"Cosmic Vision","startTime":2941.77,"endTime":2944.923,"body":"and a nice warm building."},{"speaker":"Cosmic Vision","startTime":2946.21,"endTime":2948.22,"body":"The problem is the following,"},{"speaker":"Cosmic Vision","startTime":2948.22,"endTime":2951.13,"body":"that hydrocarbons, such as coal and oil,"},{"speaker":"Cosmic Vision","startTime":2951.13,"endTime":2954.07,"body":"are the buried products of solar energy,"},{"speaker":"Cosmic Vision","startTime":2954.07,"endTime":2956.95,"body":"photosynthesis, and geological pressure"},{"speaker":"Cosmic Vision","startTime":2956.95,"endTime":2961.033,"body":"that formed over a few"},{"speaker":"Cosmic Vision","startTime":2956.95,"endTime":2961.033,"body":"hundred million years."},{"speaker":"Cosmic Vision","startTime":2963.19,"endTime":2965.56,"body":"Fossil fuels, like coal and oil,"},{"speaker":"Cosmic Vision","startTime":2965.56,"endTime":2968.263,"body":"are the sequestration of CO2,"},{"speaker":"Cosmic Vision","startTime":2969.22,"endTime":2971.35,"body":"the storage of CO2,"},{"speaker":"Cosmic Vision","startTime":2971.35,"endTime":2974.05,"body":"keeping it out of the atmosphere"},{"speaker":"Cosmic Vision","startTime":2974.05,"endTime":2978.823,"body":"in a way that certainly no"},{"speaker":"Cosmic Vision","startTime":2974.05,"endTime":2978.823,"body":"longer happens on Venus."},{"speaker":"Cosmic Vision","startTime":2979.99,"endTime":2981.91,"body":"But these same fossil fuels"},{"speaker":"Cosmic Vision","startTime":2981.91,"endTime":2985.45,"body":"have fueled our industries"},{"speaker":"Cosmic Vision","startTime":2981.91,"endTime":2985.45,"body":"and our transport"},{"speaker":"Cosmic Vision","startTime":2985.45,"endTime":2988.543,"body":"since the beginning of"},{"speaker":"Cosmic Vision","startTime":2985.45,"endTime":2988.543,"body":"the Industrial Revolution."},{"speaker":"Cosmic Vision","startTime":2990.04,"endTime":2994.6,"body":"On a cheerier note, energy"},{"speaker":"Cosmic Vision","startTime":2990.04,"endTime":2994.6,"body":"from the Sun is enormous."},{"speaker":"Cosmic Vision","startTime":2994.6,"endTime":2998.2,"body":"It's something like"},{"speaker":"Cosmic Vision","startTime":2994.6,"endTime":2998.2,"body":"100,000 terawatts of energy"},{"speaker":"Cosmic Vision","startTime":2998.2,"endTime":3000.57,"body":"that the Sun provides."},{"speaker":"Cosmic Vision","startTime":3000.57,"endTime":3002.94,"body":"The energy from one hour of sunlight"},{"speaker":"Cosmic Vision","startTime":3002.94,"endTime":3004.86,"body":"is equivalent to all the energy"},{"speaker":"Cosmic Vision","startTime":3004.86,"endTime":3008.553,"body":"that humankind currently uses in a year."},{"speaker":"Cosmic Vision","startTime":3009.48,"endTime":3012.48,"body":"And it is fusion energy, by the way,"},{"speaker":"Cosmic Vision","startTime":3012.48,"endTime":3016.863,"body":"but harnessing it at a"},{"speaker":"Cosmic Vision","startTime":3012.48,"endTime":3016.863,"body":"distance of 93 million miles."},{"speaker":"Cosmic Vision","startTime":3017.7,"endTime":3021.36,"body":"Each square meter on average"},{"speaker":"Cosmic Vision","startTime":3017.7,"endTime":3021.36,"body":"of the illuminated Earth"},{"speaker":"Cosmic Vision","startTime":3021.36,"endTime":3023.493,"body":"receives about a kilowatt of energy."},{"speaker":"Cosmic Vision","startTime":3024.626,"endTime":3026.04,"body":"But I wouldn't want you to think"},{"speaker":"Cosmic Vision","startTime":3026.04,"endTime":3028.98,"body":"that I think solar energy is the only way"},{"speaker":"Cosmic Vision","startTime":3028.98,"endTime":3030.84,"body":"that we should be powering Earth"},{"speaker":"Cosmic Vision","startTime":3030.84,"endTime":3032.463,"body":"going forwards in the future."},{"speaker":"Cosmic Vision","startTime":3033.36,"endTime":3036.72,"body":"I reckon that we need all"},{"speaker":"Cosmic Vision","startTime":3033.36,"endTime":3036.72,"body":"the tools in the toolkit."},{"speaker":"Cosmic Vision","startTime":3036.72,"endTime":3041.033,"body":"I don't think any one method"},{"speaker":"Cosmic Vision","startTime":3036.72,"endTime":3041.033,"body":"for providing the energy"},{"speaker":"Cosmic Vision","startTime":3041.94,"endTime":3044.193,"body":"that we need here on Earth is perfect,"},{"speaker":"Cosmic Vision","startTime":3045.03,"endTime":3048.42,"body":"but it's true that better"},{"speaker":"Cosmic Vision","startTime":3045.03,"endTime":3048.42,"body":"is the enemy of good."},{"speaker":"Cosmic Vision","startTime":3048.42,"endTime":3053.04,"body":"We really do need all"},{"speaker":"Cosmic Vision","startTime":3048.42,"endTime":3053.04,"body":"the tools in the toolkit."},{"speaker":"Cosmic Vision","startTime":3053.04,"endTime":3057.54,"body":"We mustn't be put off by"},{"speaker":"Cosmic Vision","startTime":3053.04,"endTime":3057.54,"body":"the cacophony of soundbites"},{"speaker":"Cosmic Vision","startTime":3057.54,"endTime":3059.733,"body":"from those who are in denial."},{"speaker":"Cosmic Vision","startTime":3061.02,"endTime":3065.4,"body":"I want to really recommend to"},{"speaker":"Cosmic Vision","startTime":3061.02,"endTime":3065.4,"body":"you another course of lectures"},{"speaker":"Cosmic Vision","startTime":3065.4,"endTime":3068.4,"body":"that's starting at Gresham this term"},{"speaker":"Cosmic Vision","startTime":3068.4,"endTime":3071.58,"body":"by my Oxford colleague, Myles Allen,"},{"speaker":"Cosmic Vision","startTime":3071.58,"endTime":3073.47,"body":"now my Gresham colleague,"},{"speaker":"Cosmic Vision","startTime":3073.47,"endTime":3077.103,"body":"recently appointed as Gresham"},{"speaker":"Cosmic Vision","startTime":3073.47,"endTime":3077.103,"body":"Professor for the Environment."},{"speaker":"Cosmic Vision","startTime":3078.676,"endTime":3081.03,"body":"He's going to talk"},{"speaker":"Cosmic Vision","startTime":3078.676,"endTime":3081.03,"body":"about the what, the why,"},{"speaker":"Cosmic Vision","startTime":3081.03,"endTime":3083.28,"body":"and the how of net zero."},{"speaker":"Cosmic Vision","startTime":3083.28,"endTime":3087.213,"body":"And I really encourage you"},{"speaker":"Cosmic Vision","startTime":3083.28,"endTime":3087.213,"body":"to learn more about it."},{"speaker":"Cosmic Vision","startTime":3089.58,"endTime":3092.55,"body":"There is no doubt that the situation"},{"speaker":"Cosmic Vision","startTime":3092.55,"endTime":3096.21,"body":"that we find ourselves"},{"speaker":"Cosmic Vision","startTime":3092.55,"endTime":3096.21,"body":"here on planet Earth"},{"speaker":"Cosmic Vision","startTime":3096.21,"endTime":3098.34,"body":"is a bit precarious."},{"speaker":"Cosmic Vision","startTime":3098.34,"endTime":3099.843,"body":"It's a bit fragile."},{"speaker":"Cosmic Vision","startTime":3100.83,"endTime":3105.15,"body":"But I hope I've given you a"},{"speaker":"Cosmic Vision","startTime":3100.83,"endTime":3105.15,"body":"sense in comparison with Venus"},{"speaker":"Cosmic Vision","startTime":3105.15,"endTime":3107.67,"body":"that we have a lot to be thankful for"},{"speaker":"Cosmic Vision","startTime":3107.67,"endTime":3110.343,"body":"and a lot that is worth saving."},{"speaker":"Cosmic Vision","startTime":3111.24,"endTime":3114.693,"body":"At present, we have it"},{"speaker":"Cosmic Vision","startTime":3111.24,"endTime":3114.693,"body":"pretty good here on Earth."},{"speaker":"Cosmic Vision","startTime":3116.49,"endTime":3119.4,"body":"Many situations across the planet"},{"speaker":"Cosmic Vision","startTime":3119.4,"endTime":3122.16,"body":"are wonderful and are hospitable."},{"speaker":"Cosmic Vision","startTime":3122.16,"endTime":3125.37,"body":"But we do need to engage"},{"speaker":"Cosmic Vision","startTime":3122.16,"endTime":3125.37,"body":"our thinking brains"},{"speaker":"Cosmic Vision","startTime":3125.37,"endTime":3127.41,"body":"if we're going to preserve that"},{"speaker":"Cosmic Vision","startTime":3127.41,"endTime":3132.41,"body":"and if we're going to avert"},{"speaker":"Cosmic Vision","startTime":3127.41,"endTime":3132.41,"body":"catastrophic climate change."},{"speaker":"Cosmic Vision","startTime":3133.02,"endTime":3136.65,"body":"The end of this planetary atmosphere,"},{"speaker":"Cosmic Vision","startTime":3136.65,"endTime":3141.65,"body":"the end of the atmosphere on"},{"speaker":"Cosmic Vision","startTime":3136.65,"endTime":3141.65,"body":"planet Earth will be a thing"},{"speaker":"Cosmic Vision","startTime":3141.75,"endTime":3144.273,"body":"if we don't change tack."},{"speaker":"Cosmic Vision","startTime":3145.74,"endTime":3149.427,"body":"Let us resolve, in the"},{"speaker":"Cosmic Vision","startTime":3145.74,"endTime":3149.427,"body":"words that the school"},{"speaker":"Cosmic Vision","startTime":3151.32,"endTime":3155.07,"body":"that plays host to one of"},{"speaker":"Cosmic Vision","startTime":3151.32,"endTime":3155.07,"body":"my telescopes in India says,"},{"speaker":"Cosmic Vision","startTime":3155.07,"endTime":3160.07,"body":"let us resolve to go"},{"speaker":"Cosmic Vision","startTime":3155.07,"endTime":3160.07,"body":"green before green goes."},{"speaker":"Cosmic Vision","startTime":3161.64,"endTime":3164.153,"body":"And that is the end of today's lecture."},{"speaker":"Cosmic Vision","startTime":3164.153,"endTime":3165.086,"body":"Thank you."},{"speaker":"Cosmic Vision","startTime":3165.086,"endTime":3168.253,"body":"(audience applauding)"},{"speaker":"Cosmic Vision","startTime":3170.85,"endTime":3174.09,"body":"- Whatever happened about"},{"speaker":"Cosmic Vision","startTime":3170.85,"endTime":3174.09,"body":"the reports two years ago"},{"speaker":"Cosmic Vision","startTime":3174.09,"endTime":3176.61,"body":"of finding phosphine on Venus?"},{"speaker":"Cosmic Vision","startTime":3176.61,"endTime":3178.383,"body":"Is that a possible sign of life?"},{"speaker":"Cosmic Vision","startTime":3179.25,"endTime":3181.25,"body":"- Thank you very much for that question."},{"speaker":"Cosmic Vision","startTime":3182.46,"endTime":3184.533,"body":"So the measurements of phosphine,"},{"speaker":"Cosmic Vision","startTime":3185.49,"endTime":3187.41,"body":"which is quite an interesting molecule,"},{"speaker":"Cosmic Vision","startTime":3187.41,"endTime":3189.21,"body":"a little more complex"},{"speaker":"Cosmic Vision","startTime":3189.21,"endTime":3192.0,"body":"than the ones I've been"},{"speaker":"Cosmic Vision","startTime":3189.21,"endTime":3192.0,"body":"talking about this evening."},{"speaker":"Cosmic Vision","startTime":3192.0,"endTime":3196.32,"body":"There were reports by very"},{"speaker":"Cosmic Vision","startTime":3192.0,"endTime":3196.32,"body":"reputable scientists, by the way,"},{"speaker":"Cosmic Vision","startTime":3196.32,"endTime":3200.133,"body":"that this had been discovered"},{"speaker":"Cosmic Vision","startTime":3196.32,"endTime":3200.133,"body":"in the atmosphere of Venus."},{"speaker":"Cosmic Vision","startTime":3200.133,"endTime":3201.93,"body":"Now, this was a startling result"},{"speaker":"Cosmic Vision","startTime":3201.93,"endTime":3205.83,"body":"because the levels at"},{"speaker":"Cosmic Vision","startTime":3201.93,"endTime":3205.83,"body":"which it was detected,"},{"speaker":"Cosmic Vision","startTime":3205.83,"endTime":3208.35,"body":"or at least the levels"},{"speaker":"Cosmic Vision","startTime":3205.83,"endTime":3208.35,"body":"at which it was reported,"},{"speaker":"Cosmic Vision","startTime":3208.35,"endTime":3212.85,"body":"were so high that you could"},{"speaker":"Cosmic Vision","startTime":3208.35,"endTime":3212.85,"body":"only have explained it"},{"speaker":"Cosmic Vision","startTime":3212.85,"endTime":3215.31,"body":"from a biological origin."},{"speaker":"Cosmic Vision","startTime":3215.31,"endTime":3220.31,"body":"In other words, if the detection"},{"speaker":"Cosmic Vision","startTime":3215.31,"endTime":3220.31,"body":"turned out to be for real,"},{"speaker":"Cosmic Vision","startTime":3220.44,"endTime":3223.95,"body":"it would've been a very clear indication"},{"speaker":"Cosmic Vision","startTime":3223.95,"endTime":3227.313,"body":"that life had once been present on Venus."},{"speaker":"Cosmic Vision","startTime":3228.57,"endTime":3231.96,"body":"But it's fair to say, as is"},{"speaker":"Cosmic Vision","startTime":3228.57,"endTime":3231.96,"body":"often the case in science,"},{"speaker":"Cosmic Vision","startTime":3231.96,"endTime":3234.24,"body":"that although there's"},{"speaker":"Cosmic Vision","startTime":3231.96,"endTime":3234.24,"body":"reasonably good evidence"},{"speaker":"Cosmic Vision","startTime":3234.24,"endTime":3236.85,"body":"for a detection of phosphine,"},{"speaker":"Cosmic Vision","startTime":3236.85,"endTime":3238.86,"body":"it doesn't seem to be borne out"},{"speaker":"Cosmic Vision","startTime":3238.86,"endTime":3242.97,"body":"that it's at the same high"},{"speaker":"Cosmic Vision","startTime":3238.86,"endTime":3242.97,"body":"levels of the original report."},{"speaker":"Cosmic Vision","startTime":3242.97,"endTime":3246.27,"body":"So phosphine does seem"},{"speaker":"Cosmic Vision","startTime":3242.97,"endTime":3246.27,"body":"to be present in Venus,"},{"speaker":"Cosmic Vision","startTime":3246.27,"endTime":3250.98,"body":"but, at present, the concordance"},{"speaker":"Cosmic Vision","startTime":3246.27,"endTime":3250.98,"body":"of opinion seems to be"},{"speaker":"Cosmic Vision","startTime":3250.98,"endTime":3253.71,"body":"that it's at the level"},{"speaker":"Cosmic Vision","startTime":3250.98,"endTime":3253.71,"body":"that you could explain"},{"speaker":"Cosmic Vision","startTime":3253.71,"endTime":3255.45,"body":"by non-biological processes,"},{"speaker":"Cosmic Vision","startTime":3255.45,"endTime":3257.76,"body":"processes relating to, for example,"},{"speaker":"Cosmic Vision","startTime":3257.76,"endTime":3260.76,"body":"original volcanic activity"},{"speaker":"Cosmic Vision","startTime":3257.76,"endTime":3260.76,"body":"or something like that."},{"speaker":"Cosmic Vision","startTime":3260.76,"endTime":3263.67,"body":"So we're nowhere near being able to say"},{"speaker":"Cosmic Vision","startTime":3263.67,"endTime":3267.183,"body":"that Venus ever played host"},{"speaker":"Cosmic Vision","startTime":3263.67,"endTime":3267.183,"body":"to life, I don't think."},{"speaker":"Cosmic Vision","startTime":3269.1,"endTime":3271.8,"body":"- The ground level pressure of Venus"},{"speaker":"Cosmic Vision","startTime":3271.8,"endTime":3273.21,"body":"is 90 times that of Earth's."},{"speaker":"Cosmic Vision","startTime":3273.21,"endTime":3278.19,"body":"That is hostile to humans,"},{"speaker":"Cosmic Vision","startTime":3273.21,"endTime":3278.19,"body":"but you said all life forms."},{"speaker":"Cosmic Vision","startTime":3278.19,"endTime":3282.09,"body":"Some life forms thrive near"},{"speaker":"Cosmic Vision","startTime":3278.19,"endTime":3282.09,"body":"thermal vents in the deep ocean,"},{"speaker":"Cosmic Vision","startTime":3282.09,"endTime":3286.77,"body":"so is it possible that they could exist?"},{"speaker":"Cosmic Vision","startTime":3286.77,"endTime":3287.85,"body":"- I think it probably is."},{"speaker":"Cosmic Vision","startTime":3287.85,"endTime":3289.32,"body":"And I think I should have been"},{"speaker":"Cosmic Vision","startTime":3289.32,"endTime":3291.27,"body":"a little bit more discriminating."},{"speaker":"Cosmic Vision","startTime":3291.27,"endTime":3293.37,"body":"When I said that, to all life,"},{"speaker":"Cosmic Vision","startTime":3293.37,"endTime":3298.37,"body":"I was thinking of puppies and"},{"speaker":"Cosmic Vision","startTime":3293.37,"endTime":3298.37,"body":"kittens and things like that."},{"speaker":"Cosmic Vision","startTime":3300.15,"endTime":3302.22,"body":"I think everyone would agree"},{"speaker":"Cosmic Vision","startTime":3302.22,"endTime":3304.5,"body":"that the surface pressure on Venus"},{"speaker":"Cosmic Vision","startTime":3304.5,"endTime":3307.08,"body":"would be completely hostile"},{"speaker":"Cosmic Vision","startTime":3307.08,"endTime":3309.69,"body":"to that sort of multicellular life."},{"speaker":"Cosmic Vision","startTime":3309.69,"endTime":3312.0,"body":"But to the kind of things that do survive"},{"speaker":"Cosmic Vision","startTime":3312.0,"endTime":3315.84,"body":"in these very extreme"},{"speaker":"Cosmic Vision","startTime":3312.0,"endTime":3315.84,"body":"environments in the oceans,"},{"speaker":"Cosmic Vision","startTime":3315.84,"endTime":3319.41,"body":"for sure, in principle that could survive"},{"speaker":"Cosmic Vision","startTime":3319.41,"endTime":3320.61,"body":"on the surface of Venus."},{"speaker":"Cosmic Vision","startTime":3320.61,"endTime":3323.64,"body":"And that's why, if the very high levels"},{"speaker":"Cosmic Vision","startTime":3323.64,"endTime":3326.97,"body":"of the phosphine detection"},{"speaker":"Cosmic Vision","startTime":3323.64,"endTime":3326.97,"body":"were to be borne out,"},{"speaker":"Cosmic Vision","startTime":3326.97,"endTime":3328.83,"body":"and they don't seem to be at present,"},{"speaker":"Cosmic Vision","startTime":3328.83,"endTime":3330.27,"body":"but it would be a bit of an indicator"},{"speaker":"Cosmic Vision","startTime":3330.27,"endTime":3332.103,"body":"that it was that kind of life form."},{"speaker":"Cosmic Vision","startTime":3333.96,"endTime":3336.03,"body":"- [Audience Member] You"},{"speaker":"Cosmic Vision","startTime":3333.96,"endTime":3336.03,"body":"showed an interesting plot"},{"speaker":"Cosmic Vision","startTime":3336.03,"endTime":3337.47,"body":"of the increase in temperature"},{"speaker":"Cosmic Vision","startTime":3337.47,"endTime":3341.313,"body":"with the annual variations"},{"speaker":"Cosmic Vision","startTime":3337.47,"endTime":3341.313,"body":"due to vegetation."},{"speaker":"Cosmic Vision","startTime":3342.48,"endTime":3347.48,"body":"One of the things the popular"},{"speaker":"Cosmic Vision","startTime":3342.48,"endTime":3347.48,"body":"press is always on about"},{"speaker":"Cosmic Vision","startTime":3347.82,"endTime":3351.243,"body":"in terms of global warming"},{"speaker":"Cosmic Vision","startTime":3347.82,"endTime":3351.243,"body":"is planting more forests,"},{"speaker":"Cosmic Vision","startTime":3352.29,"endTime":3354.15,"body":"but, from your graph, the effect seems"},{"speaker":"Cosmic Vision","startTime":3354.15,"endTime":3356.28,"body":"to be rather small and cyclic,"},{"speaker":"Cosmic Vision","startTime":3356.28,"endTime":3359.52,"body":"so is there any true reason"},{"speaker":"Cosmic Vision","startTime":3356.28,"endTime":3359.52,"body":"why it would be beneficial"},{"speaker":"Cosmic Vision","startTime":3359.52,"endTime":3360.663,"body":"to plant more forests?"},{"speaker":"Cosmic Vision","startTime":3362.31,"endTime":3364.05,"body":"- I think it would be a really good idea"},{"speaker":"Cosmic Vision","startTime":3364.05,"endTime":3365.88,"body":"to plant more forests and more plants"},{"speaker":"Cosmic Vision","startTime":3365.88,"endTime":3367.71,"body":"and so on and so forth."},{"speaker":"Cosmic Vision","startTime":3367.71,"endTime":3370.74,"body":"That cyclic behavior that you refer to"},{"speaker":"Cosmic Vision","startTime":3370.74,"endTime":3373.21,"body":"is just the normal growing season"},{"speaker":"Cosmic Vision","startTime":3374.79,"endTime":3378.48,"body":"in the Northern Hemisphere"},{"speaker":"Cosmic Vision","startTime":3374.79,"endTime":3378.48,"body":"which predominates this."},{"speaker":"Cosmic Vision","startTime":3378.48,"endTime":3380.17,"body":"It's not in any sense"},{"speaker":"Cosmic Vision","startTime":3381.57,"endTime":3386.413,"body":"related to a sort of very"},{"speaker":"Cosmic Vision","startTime":3381.57,"endTime":3386.413,"body":"strategic forest-wide campaign."},{"speaker":"Cosmic Vision","startTime":3389.82,"endTime":3392.16,"body":"I think there aren't"},{"speaker":"Cosmic Vision","startTime":3389.82,"endTime":3392.16,"body":"downsides to doing that,"},{"speaker":"Cosmic Vision","startTime":3392.16,"endTime":3393.72,"body":"except in very arid places,"},{"speaker":"Cosmic Vision","startTime":3393.72,"endTime":3395.46,"body":"where there wouldn't be enough water"},{"speaker":"Cosmic Vision","startTime":3395.46,"endTime":3397.08,"body":"for these things to grow."},{"speaker":"Cosmic Vision","startTime":3397.08,"endTime":3399.693,"body":"I think it would be a very"},{"speaker":"Cosmic Vision","startTime":3397.08,"endTime":3399.693,"body":"worthwhile thing to do."},{"speaker":"Cosmic Vision","startTime":3401.16,"endTime":3402.66,"body":"I don't think it would be sufficient."},{"speaker":"Cosmic Vision","startTime":3402.66,"endTime":3407.07,"body":"I think we need to stop putting"},{"speaker":"Cosmic Vision","startTime":3402.66,"endTime":3407.07,"body":"more CO2 into our atmosphere"},{"speaker":"Cosmic Vision","startTime":3407.07,"endTime":3408.9,"body":"as well as what you suggest."},{"speaker":"Cosmic Vision","startTime":3408.9,"endTime":3411.753,"body":"We need all the tools in the toolkit."},{"speaker":"Cosmic Vision","startTime":3413.52,"endTime":3418.52,"body":"There's no single silver"},{"speaker":"Cosmic Vision","startTime":3413.52,"endTime":3418.52,"body":"bullet solution, sadly."},{"speaker":"Cosmic Vision","startTime":3418.553,"endTime":3420.363,"body":"- [Audience Member] My question is,"},{"speaker":"Cosmic Vision","startTime":3423.194,"endTime":3424.83,"body":"the heat which you're talking about,"},{"speaker":"Cosmic Vision","startTime":3424.83,"endTime":3429.75,"body":"the energy, which is enabling"},{"speaker":"Cosmic Vision","startTime":3424.83,"endTime":3429.75,"body":"all the planets to survive,"},{"speaker":"Cosmic Vision","startTime":3429.75,"endTime":3432.78,"body":"have a time limit because of the Sun,"},{"speaker":"Cosmic Vision","startTime":3432.78,"endTime":3435.3,"body":"which will use up its energy."},{"speaker":"Cosmic Vision","startTime":3435.3,"endTime":3439.05,"body":"So, when that happens,"},{"speaker":"Cosmic Vision","startTime":3439.05,"endTime":3442.89,"body":"will all the planets, the"},{"speaker":"Cosmic Vision","startTime":3439.05,"endTime":3442.89,"body":"entire solar system disappear,"},{"speaker":"Cosmic Vision","startTime":3442.89,"endTime":3445.263,"body":"you know, get absorbed in the Sun?"},{"speaker":"Cosmic Vision","startTime":3446.28,"endTime":3449.91,"body":"The other question which was"},{"speaker":"Cosmic Vision","startTime":3446.28,"endTime":3449.91,"body":"connected to that is that,"},{"speaker":"Cosmic Vision","startTime":3449.91,"endTime":3452.7,"body":"the international situation being so bad,"},{"speaker":"Cosmic Vision","startTime":3452.7,"endTime":3454.02,"body":"suppose, for instance,"},{"speaker":"Cosmic Vision","startTime":3454.02,"endTime":3456.81,"body":"that there was nuclear"},{"speaker":"Cosmic Vision","startTime":3454.02,"endTime":3456.81,"body":"bombs all over the place."},{"speaker":"Cosmic Vision","startTime":3456.81,"endTime":3461.81,"body":"Would that cause global"},{"speaker":"Cosmic Vision","startTime":3456.81,"endTime":3461.81,"body":"warming among other things?"},{"speaker":"Cosmic Vision","startTime":3461.851,"endTime":3463.47,"body":"(audience laughs)"},{"speaker":"Cosmic Vision","startTime":3463.47,"endTime":3467.04,"body":"- So, to take your second question first,"},{"speaker":"Cosmic Vision","startTime":3467.04,"endTime":3469.29,"body":"I think there would be so many bad things"},{"speaker":"Cosmic Vision","startTime":3469.29,"endTime":3472.68,"body":"if the international"},{"speaker":"Cosmic Vision","startTime":3469.29,"endTime":3472.68,"body":"situation were to lead"},{"speaker":"Cosmic Vision","startTime":3472.68,"endTime":3475.78,"body":"to nuclear attack"},{"speaker":"Cosmic Vision","startTime":3477.154,"endTime":3479.52,"body":"in certain locations."},{"speaker":"Cosmic Vision","startTime":3479.52,"endTime":3481.92,"body":"Would it lead to a nuclear winter?"},{"speaker":"Cosmic Vision","startTime":3481.92,"endTime":3482.94,"body":"It's really not clear."},{"speaker":"Cosmic Vision","startTime":3482.94,"endTime":3486.06,"body":"It depends on the"},{"speaker":"Cosmic Vision","startTime":3482.94,"endTime":3486.06,"body":"specificity of the attack."},{"speaker":"Cosmic Vision","startTime":3486.06,"endTime":3488.49,"body":"To go back to your first question,"},{"speaker":"Cosmic Vision","startTime":3488.49,"endTime":3492.45,"body":"the expiry of the Sun and the"},{"speaker":"Cosmic Vision","startTime":3488.49,"endTime":3492.45,"body":"implications for the planets"},{"speaker":"Cosmic Vision","startTime":3492.45,"endTime":3494.52,"body":"across the solar system,"},{"speaker":"Cosmic Vision","startTime":3494.52,"endTime":3497.04,"body":"that is entirely the subject"},{"speaker":"Cosmic Vision","startTime":3497.04,"endTime":3499.567,"body":"of my next Gresham lecture in November."},{"speaker":"Cosmic Vision","startTime":3499.567,"endTime":3501.059,"body":"(audience laughs)"},{"speaker":"Cosmic Vision","startTime":3501.059,"endTime":3501.99,"body":"- And with that,"},{"speaker":"Cosmic Vision","startTime":3501.99,"endTime":3504.383,"body":"that is all the time"},{"speaker":"Cosmic Vision","startTime":3501.99,"endTime":3504.383,"body":"we've got for questions."},{"speaker":"Cosmic Vision","startTime":3504.383,"endTime":3505.275,"body":"Thank you, everybody,"},{"speaker":"Cosmic Vision","startTime":3505.275,"endTime":3506.837,"body":"and thank you again, Katherine."},{"speaker":"Cosmic Vision","startTime":3506.837,"endTime":3509.657,"body":"(audience applauding)"}]}