{"version":"1.0.0","segments":[{"startTime":5.625,"endTime":9.805,"body":"As an astronomer, I'd always wondered when the news would reach me."},{"startTime":9.805,"endTime":14.487,"body":"And as it turned out, it was sitting on my kitchen doorstep with my feet"},{"startTime":14.487,"endTime":14.799,"body":"out of the porch in the August sunshine in the strangest of years, 2020 when"},{"startTime":14.799,"endTime":15.111,"body":"the call finally came through, the voice on the other end of the phone was"},{"startTime":15.111,"endTime":24.165,"body":"Dr."},{"startTime":24.165,"endTime":29.405,"body":"Chris North, an old sky at night, colleague of mine now cosmologist at Cardiff University."},{"startTime":29.945,"endTime":33.645,"body":"And what he said may have changed my view of the universe forever."},{"startTime":34.175,"endTime":39.525,"body":"Chris, on the other end of the phone said, well, it could be Venusians."},{"startTime":40.425,"endTime":45.173,"body":"He was ringing with the news of a discovery made by his colleague Jane Greaves,"},{"startTime":45.173,"endTime":49.605,"body":"also at Cardiff, of a chemical called Phosphine found in the atmosphere of Venus."},{"startTime":49.825,"endTime":51.725,"body":"And Phosphine is a simple molecule."},{"startTime":52.515,"endTime":55.725,"body":"It's nothing more than a phosphorus atom with three hydrogens attached."},{"startTime":55.985,"endTime":60.685,"body":"But it's exciting because on Earth, it's only produced by life."},{"startTime":61.475,"endTime":66.696,"body":"It's only produced by artificial processes that we use in factories, or it's produced by"},{"startTime":66.696,"endTime":67.045,"body":"animals."},{"startTime":67.165,"endTime":72.495,"body":"A particular rich source, uh, is, um, well, our penguins, uh, in what I've been"},{"startTime":72.495,"endTime":76.405,"body":"told by Gresham to describe as their guano, uh, their droppings."},{"startTime":76.625,"endTime":80.045,"body":"Uh, and in fact, this has been used to spot penguins from space."},{"startTime":80.625,"endTime":84.861,"body":"So this is a satellite picture of part of the Antarctic Peninsula, um, courtesy of"},{"startTime":84.861,"endTime":87.685,"body":"the British Antarctic Survey and, and the European Space Agency."},{"startTime":87.865,"endTime":92.165,"body":"And the little black markings you can see labeled there, uh, let's just say indicate"},{"startTime":92.165,"endTime":93.885,"body":"the presence of lots of penguins."},{"startTime":94.865,"endTime":101.776,"body":"And so, Jane's discovery of Phosphine in the Venusian atmosphere, um, may have indicated the"},{"startTime":101.776,"endTime":106.845,"body":"presence of small Venusian penguins flying around, uh, in the atmosphere."},{"startTime":107.115,"endTime":112.166,"body":"More generally, it's a biomarker, uh, uh, a bio signature to some, uh, a chemical,"},{"startTime":112.166,"endTime":112.502,"body":"which when we see it, we think indicates the presence of life and finding phosphine,"},{"startTime":112.502,"endTime":112.839,"body":"therefore anywhere in the universe, but anywhere in the solar system would've come as a"},{"startTime":112.839,"endTime":122.605,"body":"surprise."},{"startTime":122.665,"endTime":127.8,"body":"The fact it was Venus, a world so in a hospitable, that if you landed"},{"startTime":127.8,"endTime":128.143,"body":"and stepped out of your spacecraft, you'd be crushed, dissolved, suffocate, and boiled, um, all"},{"startTime":128.143,"endTime":137.045,"body":"within the space of a few minutes, um, was, was really surprising."},{"startTime":137.105,"endTime":139.205,"body":"We, we have explored the surface of Venus."},{"startTime":139.205,"endTime":144.862,"body":"This picture was sent back by the Veneer nine probe, uh, Soviet probe that touched"},{"startTime":144.862,"endTime":147.125,"body":"down 48 years ago this weekend."},{"startTime":147.825,"endTime":152.445,"body":"Um, and lasted for a whole 53 minutes on the surface before melting."},{"startTime":152.945,"endTime":155.085,"body":"Um, but it did send back this one picture."},{"startTime":155.705,"endTime":161.191,"body":"Um, but it does indicate how in Hoss inhospitable Venus is, the planet is a"},{"startTime":161.191,"endTime":161.557,"body":"roughly the same size as Earth, but it has this thick atmosphere, thick acidic atmosphere,"},{"startTime":161.557,"endTime":169.605,"body":"which makes it a very unpleasant place indeed."},{"startTime":170.665,"endTime":174.805,"body":"So how and why had Jane and Co looked for Phosphine on Venus?"},{"startTime":174.955,"endTime":178.485,"body":"Well, it started off really a as, as a point of principle."},{"startTime":178.785,"endTime":182.442,"body":"Um, people have talked, as I'll get onto it, a bit of looking for Biosignatures"},{"startTime":182.442,"endTime":185.125,"body":"for trying to detect the signs of life on distant planets."},{"startTime":185.545,"endTime":189.489,"body":"And so in a kind of visionary way, Jane and co thought they should look,"},{"startTime":189.489,"endTime":192.645,"body":"uh, nearby as well to show that the telescopes could do this."},{"startTime":192.945,"endTime":198.695,"body":"Um, and the telescopes you use to look for phosphine, um, or any other molecule,"},{"startTime":198.695,"endTime":199.845,"body":"aren't optical telescopes."},{"startTime":199.845,"endTime":200.845,"body":"They don't involve mirrors."},{"startTime":200.845,"endTime":202.125,"body":"They, they look rather odd."},{"startTime":202.125,"endTime":207.987,"body":"This is the James Clark Maxwell telescope, the JCMT, um, high up on the summit"},{"startTime":207.987,"endTime":208.378,"body":"of Monarchia, uh, the central Volcano, uh, hopefully dormant, uh, on the big island of"},{"startTime":208.378,"endTime":208.769,"body":"Hawaii, sacred sites to native Hawaiians and home to some of the best, uh, observing"},{"startTime":208.769,"endTime":220.885,"body":"on the planet."},{"startTime":221.345,"endTime":224.805,"body":"Um, inside this structure, there's a 15 meter radio dish."},{"startTime":225.355,"endTime":230.311,"body":"It's protected from the elements by this shield, which, uh, according to publicity on their"},{"startTime":230.311,"endTime":233.285,"body":"website, it's the world's second largest piece of Gore-Tex."},{"startTime":233.905,"endTime":237.805,"body":"Um, if anyone knows where the largest piece is, I've tried looking and I, I"},{"startTime":237.805,"endTime":238.325,"body":"don't know."},{"startTime":238.585,"endTime":241.903,"body":"So, so one day somebody's gonna turn up, come up after a lecture and tell"},{"startTime":241.903,"endTime":242.125,"body":"me."},{"startTime":242.545,"endTime":248.195,"body":"Um, but this is a radio dish attuned to the kind of frequencies that your"},{"startTime":248.195,"endTime":249.325,"body":"microwave oven uses."},{"startTime":249.705,"endTime":253.925,"body":"Uh, it's very short wave radio, what the astronomers called sub-millimeter."},{"startTime":254.105,"endTime":255.325,"body":"And that's not a coincidence."},{"startTime":255.325,"endTime":260.805,"body":"Your microwave bombards your food with radiation at a frequency that makes water vibrate."},{"startTime":261.105,"endTime":262.365,"body":"That's how it heats."},{"startTime":262.905,"endTime":266.285,"body":"And so lots of small molecules vibrate at these frequencies."},{"startTime":266.305,"endTime":270.64,"body":"And so by tuning our radio telescopes to them, we can detect all sorts of"},{"startTime":270.64,"endTime":272.085,"body":"things in, in the cosmos."},{"startTime":272.785,"endTime":275.885,"body":"Um, that's also incidentally why this thing's on top of a mountain."},{"startTime":275.985,"endTime":280.045,"body":"It needs to be up above most of the Earth's atmosphere."},{"startTime":280.045,"endTime":284.276,"body":"You need to be above the water in the atmosphere or all that you detect"},{"startTime":284.276,"endTime":285.405,"body":"is our own planet."},{"startTime":285.885,"endTime":290.397,"body":"I, myself, once spent a happy couple of days making an independent discovery of ozone"},{"startTime":290.397,"endTime":293.405,"body":"in the earth's atmosphere by accident, uh, at the JCMT."},{"startTime":294.225,"endTime":297.812,"body":"And there was also a, a telescope called Alma, uh, which we'll come to in"},{"startTime":297.812,"endTime":299.965,"body":"a second in Chile, which backed up the observation."},{"startTime":299.985,"endTime":305.605,"body":"So Jane had two sets of telescopes, which had detected this molecule."},{"startTime":305.605,"endTime":306.845,"body":"Now it's a difficult measurement."},{"startTime":306.955,"endTime":313.725,"body":"There's not much phosphine and Venus itself is really bright at these wavelengths."},{"startTime":313.725,"endTime":318.037,"body":"So it's like trying to stargaze while looking at a stadium floodlight, but with careful"},{"startTime":318.037,"endTime":318.325,"body":"processing."},{"startTime":318.705,"endTime":322.662,"body":"Uh, after a couple of years, Jane and her team were able to pull out,"},{"startTime":322.662,"endTime":324.245,"body":"uh, the signature of this thing."},{"startTime":324.245,"endTime":329.89,"body":"And actually they could even work out where in the atmosphere the phosphine was based"},{"startTime":329.89,"endTime":332.525,"body":"on the signature that they were seeing."},{"startTime":332.525,"endTime":336.914,"body":"And here it gets really interesting 'cause it turns out that it's not distributed throughout"},{"startTime":336.914,"endTime":337.207,"body":"the atmosphere, but it's in a layer high above the Venusian surface in the very"},{"startTime":337.207,"endTime":343.645,"body":"upper layers of the atmosphere of the planet."},{"startTime":344.385,"endTime":350.179,"body":"And if you ask what the conditions are like at that height above the surface,"},{"startTime":350.179,"endTime":351.725,"body":"they're much more hospitable."},{"startTime":352.265,"endTime":356.919,"body":"Um, they're, uh, about the same atmospheric pressure as we have at sea level on"},{"startTime":356.919,"endTime":357.23,"body":"earth."},{"startTime":357.985,"endTime":362.405,"body":"And, um, the temperature is about the same as a British Summer's day."},{"startTime":362.465,"endTime":365.565,"body":"So about 15 degrees centigrade, something like something like that."},{"startTime":365.895,"endTime":368.285,"body":"Guess that that joke's slightly out of date these days."},{"startTime":368.425,"endTime":371.045,"body":"But, but anyway, you get, you, you, you get the I idea."},{"startTime":371.465,"endTime":376.845,"body":"Um, it is still acidic and acid is bad news, we think for life."},{"startTime":377.065,"endTime":381.742,"body":"Um, a point demonstrated in the sky at night program that we made by chemist"},{"startTime":381.742,"endTime":385.485,"body":"William Bains, one of the James team, um, who took great delight."},{"startTime":385.725,"endTime":390.502,"body":"Chemists are always delighted to pour acid on things, I find, uh, and he demonstrated"},{"startTime":390.502,"endTime":394.325,"body":"that acid was bad for life by, uh, pouring it on toast."},{"startTime":394.825,"endTime":399.982,"body":"Uh, and for some reason mushy peas, uh, I'm not quite sure why those things,"},{"startTime":399.982,"endTime":402.045,"body":"but they definitely shriveled, uh, alarmingly."},{"startTime":402.385,"endTime":407.857,"body":"Um, so though this is an acidic environment high in the atmosphere, it might be"},{"startTime":407.857,"endTime":412.965,"body":"a home for life, uh, that we weren't expecting amongst the clouds of Venus."},{"startTime":414.545,"endTime":417.645,"body":"And so that gives you this rather romantic story."},{"startTime":418.125,"endTime":423.075,"body":"I think about this little colony of presumably not penguins, but I know acid resistant"},{"startTime":423.075,"endTime":423.405,"body":"bacteria."},{"startTime":424.255,"endTime":428.939,"body":"Venus, when it formed four and a half, 4.8 billion years ago, along with the"},{"startTime":428.939,"endTime":431.125,"body":"Earth, may have been a temperate world."},{"startTime":431.745,"endTime":436.861,"body":"It may have had a climate, uh, close to, if not quite as, uh, as"},{"startTime":436.861,"endTime":437.885,"body":"mild as ours."},{"startTime":438.185,"endTime":442.845,"body":"And you can imagine that if life is easy to get started in the universe,"},{"startTime":442.845,"endTime":443.156,"body":"then that early Venus would've been a world rich in all sorts of flora and"},{"startTime":443.156,"endTime":450.925,"body":"fauna, just as life on the earth got started really quickly."},{"startTime":451.385,"endTime":457.131,"body":"And then these bacteria that maybe Jane had found are sort of the last vestiges"},{"startTime":457.131,"endTime":457.514,"body":"of an old civilization clinging on in the last habitable part of a planet that"},{"startTime":457.514,"endTime":466.325,"body":"had dramatically changed over the last 4 billion years."},{"startTime":467.105,"endTime":470.405,"body":"Uh, Venus has suffered from an extreme greenhouse effect."},{"startTime":470.545,"endTime":475.356,"body":"Its atmosphere, has thickened the water, if there ever was any on the planet, has"},{"startTime":475.356,"endTime":479.205,"body":"disappeared, and we've ended up with the hell hole that it is."},{"startTime":479.465,"endTime":479.965,"body":"Uh, today."},{"startTime":479.985,"endTime":481.805,"body":"I'm gonna try and be rude about every single planet."},{"startTime":481.985,"endTime":483.005,"body":"So that's Venus ticked off."},{"startTime":483.385,"endTime":490.355,"body":"Um, this result wasn't met with glee and excitement from everyone."},{"startTime":490.355,"endTime":494.355,"body":"People were careful not to say we had found life, just that it was a"},{"startTime":494.355,"endTime":496.755,"body":"bio signature, uh, and problems propped up pretty quickly."},{"startTime":497.675,"endTime":500.675,"body":"Alma, the other telescope that Jane and Co had used, looks like this."},{"startTime":500.705,"endTime":501.635,"body":"It's an amazing place."},{"startTime":501.635,"endTime":505.675,"body":"It's a series of dishes high on a plateau above the Chilian Andes."},{"startTime":505.705,"endTime":508.995,"body":"It's the most otherworldly place I've ever been."},{"startTime":509.065,"endTime":509.875,"body":"It's so high."},{"startTime":510.465,"endTime":513.635,"body":"That lack of oxygen is a problem for working on the site."},{"startTime":513.655,"endTime":518.046,"body":"To the extent that these dishes, which are 12 meters across, if anything goes wrong,"},{"startTime":518.046,"endTime":518.339,"body":"they're actually picked up and taken down the mountain so that the engineers can work"},{"startTime":518.339,"endTime":524.195,"body":"on them with a clear head."},{"startTime":524.755,"endTime":526.875,"body":"'cause trying to do anything at altitude is difficult."},{"startTime":527.615,"endTime":532.57,"body":"Um, it's a series of dishes where you combine the radiation from each of them"},{"startTime":532.57,"endTime":536.205,"body":"to give the impression of a much larger, more sensitive telescope."},{"startTime":536.465,"endTime":540.279,"body":"And it turned out because of the scrutiny that this phosphine discovery got, that there"},{"startTime":540.279,"endTime":541.805,"body":"was an error in the software."},{"startTime":542.345,"endTime":544.965,"body":"And so it's not clear what to make of the alma results."},{"startTime":544.995,"endTime":550.805,"body":"It's possible that the second telescope, this confirmation of phosphine, um, was an error."},{"startTime":550.805,"endTime":552.125,"body":"It might just be a software glitch."},{"startTime":552.625,"endTime":559.165,"body":"Um, and then astronomers used a telescope called Sophia, um, which is a remarkable thing."},{"startTime":559.665,"endTime":563.769,"body":"Um, it's just been decommissioned actually, but this is a 7 4 7 with a"},{"startTime":563.769,"endTime":565.685,"body":"hole cut in the, in the end."},{"startTime":565.985,"endTime":570.642,"body":"And in there there's a two and a half meter mirror, a telescope that could"},{"startTime":570.642,"endTime":571.885,"body":"observe these sub-millimeter wavelengths."},{"startTime":572.105,"endTime":573.165,"body":"And it's an amazing thing."},{"startTime":573.245,"endTime":578.13,"body":"I flow, I managed to fly on Sophia, uh, and the telescope is kept stable,"},{"startTime":578.13,"endTime":580.085,"body":"um, while the plane jostled around."},{"startTime":580.465,"endTime":583.677,"body":"And so while you're inside, you see the end of the telescope doing this, you"},{"startTime":583.677,"endTime":585.605,"body":"think, how on earth is that pointing at anything?"},{"startTime":585.605,"endTime":589.033,"body":"And then you realize it's not the telescope that's moving, it's you, uh, as you"},{"startTime":589.033,"endTime":592.005,"body":"go through the turbulence and you point the telescope by moving the plane."},{"startTime":592.145,"endTime":595.605,"body":"So you fly these quite strange routes over the Californian coast."},{"startTime":595.745,"endTime":596.605,"body":"It, it was great."},{"startTime":597.025,"endTime":600.845,"body":"Um, but they had a look for Phosphine and Venus and found absolutely nothing."},{"startTime":601.865,"endTime":606.605,"body":"And so most people thought, uh, that this result was going away."},{"startTime":607.465,"endTime":609.445,"body":"Um, that's not too surprising."},{"startTime":609.445,"endTime":615.295,"body":"If you think about Venus as an inhospitable place, um, the landscape of Venus is"},{"startTime":615.295,"endTime":615.685,"body":"dramatic."},{"startTime":615.685,"endTime":618.565,"body":"This is exaggerated in the vertical direction 10 times."},{"startTime":619.265,"endTime":624.341,"body":"But it shows, uh, Matt Mons a giant volcano, uh, on the Venusian surface, seen"},{"startTime":624.341,"endTime":627.725,"body":"from a perspective as if you were two miles up."},{"startTime":627.725,"endTime":632.714,"body":"This is actually radar data from a satellite called Magellan, uh, that orbited the planet"},{"startTime":632.714,"endTime":634.045,"body":"that you're seeing here."},{"startTime":634.465,"endTime":639.247,"body":"And this is a three meter high, sorry, three mile high volcano, five miles above"},{"startTime":639.247,"endTime":639.885,"body":"sea level."},{"startTime":640.705,"endTime":645.688,"body":"Um, and wherever you look on the Venusian surface, you see signs of this sort"},{"startTime":645.688,"endTime":646.685,"body":"of volcanic activity."},{"startTime":647.305,"endTime":650.085,"body":"And we even think the volcanoes on the surface are active."},{"startTime":651.225,"endTime":656.873,"body":"Um, we found good evidence for this recently when, um, an astronomer called Robert Herrick,"},{"startTime":656.873,"endTime":657.25,"body":"who's actually working on a probe called Veritas that will go to Venus soon, um,"},{"startTime":657.25,"endTime":657.627,"body":"looked for changes on the Venusian surface by comparing images that were taken, uh, many"},{"startTime":657.627,"endTime":668.925,"body":"months apart."},{"startTime":668.925,"endTime":672.045,"body":"These are two images at the same place taken eight months apart."},{"startTime":672.465,"endTime":674.005,"body":"And you can see there's this difference."},{"startTime":674.075,"endTime":678.509,"body":"This main vent hasn't changed, but there's now this bright area to the right that's"},{"startTime":678.509,"endTime":678.805,"body":"appeared."},{"startTime":679.465,"endTime":682.765,"body":"And this thing at the bottom, this other crater has got larger."},{"startTime":683.385,"endTime":689.291,"body":"And the contention is that this is volcanic activity observed on the surface of another"},{"startTime":689.291,"endTime":689.685,"body":"world."},{"startTime":690.465,"endTime":694.948,"body":"My other favorite thing about this discovery is that, uh, Herrick was interviewed and asked"},{"startTime":694.948,"endTime":695.247,"body":"how he'd found time to look through so much of the data, uh, to try"},{"startTime":695.247,"endTime":701.525,"body":"and find this, these quite subtle changes."},{"startTime":702.105,"endTime":705.582,"body":"And he explained that this is what he did when he was on Zoom calls"},{"startTime":705.582,"endTime":707.205,"body":"and his colleagues were boring him, \u003claugh\u003e."},{"startTime":707.305,"endTime":710.645,"body":"Um, so you can put that time to use it turns out."},{"startTime":711.785,"endTime":715.685,"body":"So we have a story where Phosphine, maybe the detection was mistaken."},{"startTime":715.995,"endTime":721.509,"body":"I've just wasted the first 15 minutes of the talk telling you about something, um,"},{"startTime":721.509,"endTime":721.877,"body":"that doesn't exist except that, except that there's other evidence around people went back into"},{"startTime":721.877,"endTime":729.965,"body":"the archives and found data from this thing."},{"startTime":730.435,"endTime":738.343,"body":"This is Pioneer Venus, an American probe that dropped four separate probes through the Venusian"},{"startTime":738.343,"endTime":739.925,"body":"clouds in 1978."},{"startTime":741.065,"endTime":746.081,"body":"One of those probes had onboard a mass spectrometer, an instrument that can weigh the"},{"startTime":746.081,"endTime":747.085,"body":"molecules that encountered."},{"startTime":747.085,"endTime":750.813,"body":"So you don't get a label, but you get a weight for each molecule, and"},{"startTime":750.813,"endTime":754.045,"body":"then you can go and match that to things you think are there."},{"startTime":754.705,"endTime":760.495,"body":"And it turned out at the, at just the right height above the surface, um,"},{"startTime":760.495,"endTime":766.285,"body":"to match the observations, there was this previously unnoticed signal of pH three of Phosphine."},{"startTime":766.665,"endTime":771.837,"body":"So this probe had seen what Jane would see many years later, and her team"},{"startTime":771.837,"endTime":775.285,"body":"had been back, used JCMT again and confirmed the detection."},{"startTime":775.285,"endTime":778.125,"body":"So there really is phosphine in the atmosphere of Venus."},{"startTime":778.325,"endTime":780.805,"body":"I think not everyone agrees, but I'm right."},{"startTime":781.185,"endTime":782.525,"body":"Um, and so is Jane."},{"startTime":782.865,"endTime":786.582,"body":"Um, and it turns out, Sophia, by the way, the, the airplane telescope didn't see"},{"startTime":786.582,"endTime":789.805,"body":"anything 'cause the amount of phosphine changes over the course of a day."},{"startTime":790.665,"endTime":795.575,"body":"So Jane had always looked by coincidence in the morning, the Venusian morning Sophia had"},{"startTime":795.575,"endTime":796.885,"body":"looked in the evening."},{"startTime":797.265,"endTime":800.845,"body":"And so sunlight affects the chemistry and we have a daily cycle."},{"startTime":801.825,"endTime":802.445,"body":"Is it life?"},{"startTime":804.845,"endTime":805.565,"body":"Probably not."},{"startTime":806.345,"endTime":808.845,"body":"Um, could be it's a bio signature on Earth."},{"startTime":809.035,"endTime":813.085,"body":"It's more likely I think that we don't understand the chemistry of the Venusian atmosphere."},{"startTime":813.465,"endTime":818.327,"body":"Um, but people are working on that now to try and determine whether there really"},{"startTime":818.327,"endTime":821.245,"body":"is life sitting, uh, in the clouds of Venus."},{"startTime":821.245,"endTime":825.021,"body":"It's fun to think that there might be, even if it turns out not to"},{"startTime":825.021,"endTime":825.525,"body":"be life."},{"startTime":825.605,"endTime":828.045,"body":"I think the Phosphine saga tells us two things."},{"startTime":829.025,"endTime":834.441,"body":"Um, one has grand implications for our view of the universe, and that's that we"},{"startTime":834.441,"endTime":835.525,"body":"are building telescopes."},{"startTime":835.585,"endTime":841.676,"body":"Now, this is a shot of a re a recent shot of what will become"},{"startTime":841.676,"endTime":844.925,"body":"the dome of the European extremely large telescope."},{"startTime":845.475,"endTime":848.045,"body":"It's the successor to the very large telescope."},{"startTime":848.915,"endTime":851.005,"body":"It's a project originally known as Owl."},{"startTime":851.285,"endTime":856.575,"body":"'cause it was going to be the overwhelmingly large telescope, but we can't afford overwhelming,"},{"startTime":856.575,"endTime":859.045,"body":"but we can afford extremely large telescopes."},{"startTime":859.045,"endTime":863.308,"body":"So this will have a mirror 39 meters across, and the dome is the size"},{"startTime":863.308,"endTime":864.445,"body":"of a football stadium."},{"startTime":865.545,"endTime":868.165,"body":"And this will see first light in a few years time."},{"startTime":868.165,"endTime":872.86,"body":"And one of the reasons we're building it is so that we can look at"},{"startTime":872.86,"endTime":873.173,"body":"planets around distant stars, measure their atmospheres, and try and conclude from those measurements, whether"},{"startTime":873.173,"endTime":880.685,"body":"there are biosignatures there, whether there are signs of life."},{"startTime":881.465,"endTime":885.13,"body":"The problem is if we can't even get our facts straight and can't even work"},{"startTime":885.13,"endTime":885.375,"body":"out what's going on in our nearest neighbor of a planet, trying to do this"},{"startTime":885.375,"endTime":891.485,"body":"on a distant star is going to be very, very difficult."},{"startTime":891.635,"endTime":894.565,"body":"I'll have more to say about that in a couple of lectures time."},{"startTime":895.785,"endTime":901.194,"body":"The other thing is that contemplating life, even being able to contemplate life on Venus,"},{"startTime":901.194,"endTime":901.554,"body":"makes a remarkable change in how we think about the habitability of the world's in"},{"startTime":901.554,"endTime":907.685,"body":"our solar system."},{"startTime":907.705,"endTime":910.445,"body":"Our, our solar systems a remarkably diverse place."},{"startTime":911.065,"endTime":916.043,"body":"We have everything from, uh, giant gas planets like Jupiter, all the way down to"},{"startTime":916.043,"endTime":916.375,"body":"small rocks, uh, asteroids named after luminaries like the Beatles or Frank Zapper, or you"},{"startTime":916.375,"endTime":916.707,"body":"know, there's one named after me, uh, which tell you how many rocks there are"},{"startTime":916.707,"endTime":928.325,"body":"if they're naming them after random astronomist."},{"startTime":928.785,"endTime":933.926,"body":"Um, but if we look at the long history of people thinking about these things,"},{"startTime":933.926,"endTime":934.269,"body":"the original assertion was that in the 18th and 19th century was that surely all"},{"startTime":934.269,"endTime":941.125,"body":"of these worlds would be habited."},{"startTime":941.785,"endTime":946.521,"body":"Um, William Herschel, the great observer I talked about a bit in the last lecture,"},{"startTime":946.521,"endTime":946.837,"body":"even went so far as to believe that the sun, which he saw as a"},{"startTime":946.837,"endTime":947.153,"body":"planet, it was a world with a landscape, um, must therefore be inhabited and solarium"},{"startTime":947.153,"endTime":958.205,"body":"would cavort, uh, uh, on its surface."},{"startTime":958.385,"endTime":959.405,"body":"Now, that's not true."},{"startTime":959.905,"endTime":963.519,"body":"If you learn nothing else today, uh, the sun does not have aliens living on"},{"startTime":963.519,"endTime":964.965,"body":"it as far as we know."},{"startTime":965.505,"endTime":971.58,"body":"Um, but almost everything else that was seen in the solar system, any mysterious phenomena"},{"startTime":971.58,"endTime":973.605,"body":"could be attributed to life."},{"startTime":973.785,"endTime":977.914,"body":"So going back to Venus, when you see a crescent Venus in the sky, and"},{"startTime":977.914,"endTime":978.19,"body":"our view at the minute in the morning, sky is not so different from this,"},{"startTime":978.19,"endTime":978.465,"body":"um, on the dark side of the planet, you sometimes see what's known as the"},{"startTime":978.465,"endTime":986.725,"body":"asen light."},{"startTime":987.425,"endTime":991.685,"body":"Um, or rather, observers have recorded the Asen light."},{"startTime":991.715,"endTime":994.605,"body":"It's this glow that appears to come on the dark side."},{"startTime":994.825,"endTime":995.765,"body":"How do we explain it?"},{"startTime":995.875,"endTime":999.725,"body":"Well, clearly it's the campfires of, of Aian civilization."},{"startTime":1000.305,"endTime":1005.237,"body":"Um, in particular, there's a wonderful period where people thought Venus would have can canals"},{"startTime":1005.237,"endTime":1008.525,"body":"or channels of soda water, uh, carbonated for your pleasure."},{"startTime":1008.525,"endTime":1012.63,"body":"So you can imagine a nice evening by your soda water canal with a campfire"},{"startTime":1012.63,"endTime":1013.725,"body":"and your favorite venusians."},{"startTime":1014.225,"endTime":1016.645,"body":"Um, Mars, of course, is obviously inhabited."},{"startTime":1017.145,"endTime":1023.755,"body":"Um, my favorite argument for life on Mars was made most forcefully by Ernst opec,"},{"startTime":1023.755,"endTime":1030.365,"body":"uh, Lambert OPEC's grandfather, uh, and an Estonian astronomer, um, who made the following argument."},{"startTime":1030.515,"endTime":1034.085,"body":"Mars has these dark patches that you see through telescopes."},{"startTime":1034.085,"endTime":1038.434,"body":"Even a small telescope with a bit of squinting and a bit of belief will"},{"startTime":1038.434,"endTime":1042.204,"body":"show you that Mars has these regular patterns of, of dark, uh, markings."},{"startTime":1042.204,"endTime":1047.584,"body":"But sometimes as in 2001, uh, a dust storm will blow up, put enough dust"},{"startTime":1047.584,"endTime":1052.965,"body":"into the atmosphere that all the markings on the surface of the planet are obscured."},{"startTime":1054.025,"endTime":1055.845,"body":"Um, this happens every few years."},{"startTime":1056.465,"endTime":1060.753,"body":"Um, you may remember such a dust storm from the film, the Martian, where it"},{"startTime":1060.753,"endTime":1061.325,"body":"causes trouble."},{"startTime":1061.865,"endTime":1066.885,"body":"Um, but after a time, the same markings reappear."},{"startTime":1067.515,"endTime":1068.845,"body":"There's an obvious explanation."},{"startTime":1069.455,"endTime":1073.485,"body":"These are plants they grow back through the dust that's deposited along them."},{"startTime":1073.515,"endTime":1074.685,"body":"That was OPEC's theory."},{"startTime":1074.955,"endTime":1075.485,"body":"It's not true."},{"startTime":1075.485,"endTime":1078.485,"body":"These are actually high areas and we know that the wind blows things off."},{"startTime":1078.485,"endTime":1082.72,"body":"But it was natural a hundred years ago to argue that this was a sign"},{"startTime":1082.72,"endTime":1083.285,"body":"of life."},{"startTime":1083.865,"endTime":1086.285,"body":"And of course, Mars is where martians come from."},{"startTime":1086.345,"endTime":1089.565,"body":"It was often believed to be the home of intelligent life."},{"startTime":1090.345,"endTime":1095.405,"body":"And in particular, at the end of the 19th century, there was a fad for"},{"startTime":1095.405,"endTime":1095.742,"body":"mapping producing maps like this one at the Martian surface that show these long linear"},{"startTime":1095.742,"endTime":1103.165,"body":"features, which were known in English as canals."},{"startTime":1103.785,"endTime":1108.401,"body":"Uh, a slight mistranslation of skipper who was an Italian observer, who was the first"},{"startTime":1108.401,"endTime":1109.325,"body":"to report them."},{"startTime":1109.665,"endTime":1114.193,"body":"Um, he called them canali in Italian, which is channels, but doesn't have the implication"},{"startTime":1114.193,"endTime":1116.005,"body":"that aliens have dug them out."},{"startTime":1116.465,"endTime":1120.679,"body":"Uh, but, uh, English speaking astronomers, these were clearly channels and there was a fad"},{"startTime":1120.679,"endTime":1122.365,"body":"for looking ever closer at Mars."},{"startTime":1122.365,"endTime":1127.72,"body":"And seeing the complexity of this network developed, um, over time, people reported that what"},{"startTime":1127.72,"endTime":1132.005,"body":"had seemed to be individual canals had doubled or even tripled up."},{"startTime":1132.385,"endTime":1137.389,"body":"And this was taken to be the expansion of the Canal network by Martians bringing"},{"startTime":1137.389,"endTime":1140.725,"body":"water from their polar caps down to the equatorial regions."},{"startTime":1141.585,"endTime":1145.285,"body":"Now, the slightly sad fact is that not everyone could see the canals."},{"startTime":1145.745,"endTime":1151.95,"body":"Um, they were particularly, uh, spotted by our observers at Mars Hill, the big American"},{"startTime":1151.95,"endTime":1153.605,"body":"observatory in Flagstaff, Arizona."},{"startTime":1154.075,"endTime":1160.35,"body":"That was, um, established by Percival Lowell, um, uh, businessmen and philanthropist to look for"},{"startTime":1160.35,"endTime":1161.605,"body":"life on Mars."},{"startTime":1162.065,"endTime":1166.377,"body":"Uh, and there are various confused accounts of European astronomers or British astronomers who can't"},{"startTime":1166.377,"endTime":1166.665,"body":"see these things and arguments in the journals at the time by people pointing out"},{"startTime":1166.665,"endTime":1173.565,"body":"that if you can't see them, then it's your fault."},{"startTime":1173.625,"endTime":1176.045,"body":"You clearly don't have a good enough telescope or good enough eyes."},{"startTime":1176.625,"endTime":1180.445,"body":"Um, the canals are illusionary illusionary."},{"startTime":1180.865,"endTime":1185.055,"body":"Um, for years the explanation was that it was an optical effect, that people were"},{"startTime":1185.055,"endTime":1185.335,"body":"seeing craters that were just outta vision, and then your brain joins them up into"},{"startTime":1185.335,"endTime":1189.805,"body":"a line."},{"startTime":1189.805,"endTime":1191.205,"body":"It turns out even that's not true."},{"startTime":1191.675,"endTime":1194.685,"body":"They don't really trace, uh, any particular features."},{"startTime":1194.685,"endTime":1198.645,"body":"People were seeing what they wanted to see on the Martian surface."},{"startTime":1200.625,"endTime":1205.533,"body":"And as people thought seriously about conditions on Mars, a smaller planet than the Earth"},{"startTime":1205.533,"endTime":1205.86,"body":"one with a very thin atmosphere, it became clear that at least our kind of"},{"startTime":1205.86,"endTime":1212.405,"body":"life couldn't survive on the surface."},{"startTime":1213.145,"endTime":1219.265,"body":"Um, strangely it was Alfred Russell Wallace, who you might know from stories about Darwin"},{"startTime":1219.265,"endTime":1223.345,"body":"and evolution, um, who was the great popularizer of this."},{"startTime":1223.345,"endTime":1227.585,"body":"He wrote a book in 1907, um, called Is Mars Habitable."},{"startTime":1228.045,"endTime":1231.795,"body":"Uh, which is an excellent example of the rule that if a title has a"},{"startTime":1231.795,"endTime":1233.545,"body":"question in it, the answer's always no."},{"startTime":1234.325,"endTime":1238.698,"body":"Um, he showed that the the atmosphere was so thin that you couldn't have liquid"},{"startTime":1238.698,"endTime":1239.865,"body":"water on the surface."},{"startTime":1240.485,"endTime":1243.679,"body":"If you can't have liquid wor water on the surface, you can't have our kind"},{"startTime":1243.679,"endTime":1244.105,"body":"of life."},{"startTime":1244.965,"endTime":1246.185,"body":"And that was 1907."},{"startTime":1246.685,"endTime":1248.885,"body":"Um, the argument went on a little bit."},{"startTime":1249.085,"endTime":1252.965,"body":"I really like the example of a prize."},{"startTime":1253.665,"endTime":1257.644,"body":"Uh, the pre Guzman, uh, given by the French Academy at the start of the"},{"startTime":1257.644,"endTime":1257.909,"body":"20th century set up to encourage people to think about life in the solar system"},{"startTime":1257.909,"endTime":1262.685,"body":"and in the universe."},{"startTime":1263.105,"endTime":1264.565,"body":"And the academy set the rules."},{"startTime":1264.595,"endTime":1270.217,"body":"They said that they would give a hundred thousand francs to the first person to"},{"startTime":1270.217,"endTime":1273.965,"body":"communicate with a celestial body and receive a response \u003claugh\u003e."},{"startTime":1274.145,"endTime":1275.445,"body":"So you've gotta get an answer back."},{"startTime":1275.445,"endTime":1276.925,"body":"You can't just go and shout at the moon."},{"startTime":1276.925,"endTime":1277.565,"body":"That's cheating."},{"startTime":1277.945,"endTime":1282.845,"body":"Uh, but in the rules for the prize, they exclude Mars because it's too easy."},{"startTime":1283.845,"endTime":1285.885,"body":"Everyone knows that Mars is inhabited."},{"startTime":1286.425,"endTime":1290.565,"body":"And, um, people had made serious propositions to do things like build giant mirrors."},{"startTime":1290.945,"endTime":1295.32,"body":"And the idea was that you would focus light on the Martian desert and you"},{"startTime":1295.32,"endTime":1295.611,"body":"could write words in the sand, and then we would expect the martians to respond"},{"startTime":1295.611,"endTime":1301.445,"body":"by carving words into the Sahara."},{"startTime":1302.025,"endTime":1305.419,"body":"Um, how they'd know to aim for the Sahara or not, I don't know, Western"},{"startTime":1305.419,"endTime":1306.325,"body":"Europe, I'm not sure."},{"startTime":1306.705,"endTime":1309.885,"body":"Uh, but people really believed this was, uh, this was true."},{"startTime":1310.425,"endTime":1316.018,"body":"Um, there's also the pre Guzman, the the prize story ends, uh, slightly sheepishly by"},{"startTime":1316.018,"endTime":1316.391,"body":"the way, 69 years later when there's not much left of a hundred thousand francs"},{"startTime":1316.391,"endTime":1316.764,"body":"after what the first half of the 20th century's economics did, uh, to, to inflation"},{"startTime":1316.764,"endTime":1328.325,"body":"and so on."},{"startTime":1328.585,"endTime":1333.375,"body":"But they do give the prize basically to get it off the desk in 1969"},{"startTime":1333.375,"endTime":1333.695,"body":"to the Apollo 11 astronauts, because after all, they'd communicated with the celestial body and"},{"startTime":1333.695,"endTime":1339.125,"body":"received a response."},{"startTime":1339.145,"endTime":1339.685,"body":"So that's that."},{"startTime":1339.825,"endTime":1342.365,"body":"So we can close the chapter and, and move on."},{"startTime":1343.145,"endTime":1344.685,"body":"So now I've mentioned the space age."},{"startTime":1345.255,"endTime":1350.108,"body":"There was still this idea that, you know, maybe we wouldn't have martians, but in"},{"startTime":1350.108,"endTime":1350.432,"body":"we, when we are visiting Venus and Mars, there was a hope that we might"},{"startTime":1350.432,"endTime":1358.845,"body":"be seeing at least Martian bacteria, simple life or something like that."},{"startTime":1359.295,"endTime":1364.484,"body":"Venus, we've already seen, uh, proved to be in hospitable Mars from the time the"},{"startTime":1364.484,"endTime":1364.83,"body":"first Mariner four probe got to Mars and showed essentially a barren rock with craters"},{"startTime":1364.83,"endTime":1370.365,"body":"on it."},{"startTime":1370.705,"endTime":1372.805,"body":"Um, was also a disappointment."},{"startTime":1373.625,"endTime":1379.506,"body":"In the 1970s, the Viking landers, which can still claim to be I think the"},{"startTime":1379.506,"endTime":1379.898,"body":"spacecraft with probably the most sophisticated set of chemical experiments ever to land on the"},{"startTime":1379.898,"endTime":1380.29,"body":"surface of a planet, took samples as seen in this glorious painting, um, took samples,"},{"startTime":1380.29,"endTime":1396.365,"body":"took them on board, and ran tests designed explicitly to test for life."},{"startTime":1397.265,"endTime":1400.365,"body":"And at the time, the results were, were reported as negative."},{"startTime":1400.785,"endTime":1406.168,"body":"Um, since then there have been some, a minority view that the tests were a"},{"startTime":1406.168,"endTime":1407.245,"body":"bit more ambiguous."},{"startTime":1407.365,"endTime":1411.829,"body":"I think the ambiguous results can be explained by the later detection of a chemical"},{"startTime":1411.829,"endTime":1412.127,"body":"called perchlorate in the marshal soil, which makes it alkali, which I'm told is good"},{"startTime":1412.127,"endTime":1417.485,"body":"for growing a asparagus."},{"startTime":1418.025,"endTime":1421.205,"body":"So nevermind the martian and potatoes, you can do asparagus on Mars."},{"startTime":1421.465,"endTime":1422.765,"body":"Uh, but no sign of life."},{"startTime":1423.665,"endTime":1429.222,"body":"And then the missions of the sixties and seventies taught us a great deal and"},{"startTime":1429.222,"endTime":1431.445,"body":"took beautiful pictures of the planets."},{"startTime":1432.505,"endTime":1435.205,"body":"Mainly there was a sort of sense of failure."},{"startTime":1435.685,"endTime":1440.205,"body":"I think that this great goal of finding life in the solar system hadn't succeeded."},{"startTime":1440.665,"endTime":1444.876,"body":"And Viking, if you talk to people who do space policy and think about which"},{"startTime":1444.876,"endTime":1447.965,"body":"probes we should send, where Viking was seen as this disaster."},{"startTime":1448.325,"endTime":1452.845,"body":"'cause they really promoted the idea that it was gonna be a test for life."},{"startTime":1453.305,"endTime":1455.125,"body":"And then they tested for life and there wasn't any."},{"startTime":1455.745,"endTime":1459.663,"body":"And Congress and other funders concluded that therefore we didn't need to go back to"},{"startTime":1459.663,"endTime":1459.925,"body":"Mars."},{"startTime":1460.625,"endTime":1463.405,"body":"And we didn't for a very long, long while."},{"startTime":1464.145,"endTime":1469.715,"body":"The next probe following the Vikings in the seventies to land on the Martian surface"},{"startTime":1469.715,"endTime":1470.086,"body":"was the rather adorable pathfinder with the ro, which is basically AT tray on on"},{"startTime":1470.086,"endTime":1480.485,"body":"six wheels, um, which landed in 97, much later and following a new approach."},{"startTime":1481.545,"endTime":1487.302,"body":"So the goal of of Urner and Pathfinder and the missions that followed was still"},{"startTime":1487.302,"endTime":1491.525,"body":"to look for life, but they're gonna do it in stages."},{"startTime":1492.065,"endTime":1495.736,"body":"So rather than just test for life, we're now exploring Mars to see if we"},{"startTime":1495.736,"endTime":1497.205,"body":"can find the conditions for life."},{"startTime":1497.825,"endTime":1499.445,"body":"So that means finding water."},{"startTime":1500.025,"endTime":1507.242,"body":"It means finding what biochemists, wonderfully call schnapps, which is carbon, hydrogen, nitrogen, oxygen, phosphorus,"},{"startTime":1507.242,"endTime":1508.205,"body":"and sulfur."},{"startTime":1508.705,"endTime":1512.245,"body":"The atomic species, which make up organic chemistry."},{"startTime":1512.245,"endTime":1514.005,"body":"So you need to make sure that schnapps are present."},{"startTime":1514.585,"endTime":1516.245,"body":"Um, I do think it sounds like a drink."},{"startTime":1517.065,"endTime":1520.375,"body":"Uh, now you could be, you get a small glass of schnapps in some eastern"},{"startTime":1520.375,"endTime":1523.245,"body":"European bar and you forget the next two days, that sort of thing."},{"startTime":1523.665,"endTime":1526.405,"body":"Um, but this showed we could go back to Mars."},{"startTime":1526.405,"endTime":1531.355,"body":"And then the following missions revolutionized the story that we tell about Mars, so that"},{"startTime":1531.355,"endTime":1534.325,"body":"we are not talking about this barren rock anymore."},{"startTime":1535.065,"endTime":1541.015,"body":"In particular twin robot geologists spirit and opportunity, which landed in 2004, just after the"},{"startTime":1541.015,"endTime":1546.965,"body":"ill-fated British beagle probe got to the surface, but didn't quite manage to phone home."},{"startTime":1547.625,"endTime":1553.045,"body":"Um, hey, spirit and Opportunity sent back amazing pictures like this one."},{"startTime":1553.045,"endTime":1558.133,"body":"This is a place called Winter Haven where spirit sent its first winter, uh, Martian"},{"startTime":1558.133,"endTime":1561.525,"body":"winter, surviving temperatures lower than minus a hundred degrees centigrade."},{"startTime":1562.505,"endTime":1565.885,"body":"But these two rovers worked brilliantly."},{"startTime":1565.885,"endTime":1567.845,"body":"They were supposed to last for 90 days."},{"startTime":1568.355,"endTime":1573.314,"body":"Each spirit lasted for just over six years before it got stuck in a sand"},{"startTime":1573.314,"endTime":1573.645,"body":"trap."},{"startTime":1574.265,"endTime":1580.215,"body":"Um, opportunity went on to break the record for the furthest distance, traveled on a"},{"startTime":1580.215,"endTime":1586.165,"body":"celestial body, uh, traveling 28 miles in a mission that lasted, uh, nearly 15 years."},{"startTime":1587.275,"endTime":1587.765,"body":"More than that."},{"startTime":1587.765,"endTime":1589.685,"body":"Here's an opportunity photo, which is just beautiful."},{"startTime":1589.955,"endTime":1592.085,"body":"This is a place called Victoria Crater."},{"startTime":1593.235,"endTime":1599.59,"body":"More importantly than just their longevity, both probes showed us that Mars clearly had once"},{"startTime":1599.59,"endTime":1601.285,"body":"been a wet world."},{"startTime":1601.715,"endTime":1606.283,"body":"There's all sorts of evidence for this based on the fact that they're traveling across"},{"startTime":1606.283,"endTime":1606.587,"body":"things that looked like river deltas and old watercourse, but also from closeup views of"},{"startTime":1606.587,"endTime":1611.765,"body":"things like this."},{"startTime":1612.215,"endTime":1613.885,"body":"These are Martian blueberries."},{"startTime":1614.395,"endTime":1619.085,"body":"Concretions of hematite are a mineral that forms in the presence of water."},{"startTime":1619.745,"endTime":1624.497,"body":"And so the fact that these things exist tell you that this mineralogy was established"},{"startTime":1624.497,"endTime":1625.765,"body":"when Mars was wet."},{"startTime":1625.765,"endTime":1629.831,"body":"And we think that perhaps for the first billion years of its history, Mars was"},{"startTime":1629.831,"endTime":1630.645,"body":"a wet world."},{"startTime":1630.665,"endTime":1634.953,"body":"It had oceans, it had lakes, it had rivers, possibly some of those places were"},{"startTime":1634.953,"endTime":1635.525,"body":"long lived."},{"startTime":1636.585,"endTime":1644.901,"body":"And we've tried to understand what changed, why Mars went from being, um, a ver"},{"startTime":1644.901,"endTime":1650.445,"body":"oasis, um, to the desert planet that it is today."},{"startTime":1651.305,"endTime":1653.045,"body":"And one answer is that it's just small."},{"startTime":1653.745,"endTime":1659.342,"body":"So it only has a thin atmosphere, and that atmosphere will have been lost gradually,"},{"startTime":1659.342,"endTime":1659.715,"body":"uh, to the outer to outer space stripped away by the solar, wind, the particles"},{"startTime":1659.715,"endTime":1666.805,"body":"that come from the sun."},{"startTime":1667.345,"endTime":1671.776,"body":"And so, whereas Earth with a magnetic field, that protects us to some extent, Mars"},{"startTime":1671.776,"endTime":1673.845,"body":"has a very, very weak magnetic field."},{"startTime":1674.385,"endTime":1679.011,"body":"Um, and the fact that it has a weaker gravity means it's managed to lose"},{"startTime":1679.011,"endTime":1680.245,"body":"most of its water."},{"startTime":1680.745,"endTime":1681.965,"body":"Now, some of it's still there."},{"startTime":1682.855,"endTime":1686.525,"body":"There are those polar ice caps that shrink and grow with the seasons."},{"startTime":1686.905,"endTime":1693.131,"body":"Um, there is a water component to them, and we now think there might be"},{"startTime":1693.131,"endTime":1693.546,"body":"an enormous reservoir of subsurface ice as well underneath the surface, protected, uh, by the"},{"startTime":1693.546,"endTime":1693.961,"body":"Martian soil, detected by radar, um, soundings from the European Mars Express spacecraft, and, and"},{"startTime":1693.961,"endTime":1707.245,"body":"by American satellites since."},{"startTime":1707.665,"endTime":1714.305,"body":"So maybe under the surface protected from the solar radiation, maybe there's a place where"},{"startTime":1714.305,"endTime":1717.405,"body":"life clings on in Mars as well."},{"startTime":1717.405,"endTime":1721.962,"body":"We're now at the point where people are confident enough that they want to go"},{"startTime":1721.962,"endTime":1722.266,"body":"back, drill down, and start testing for life directly again, the European Franklin Rover, which"},{"startTime":1722.266,"endTime":1722.57,"body":"is sitting ready for launch, but delayed because coon with Russia, who was supposed to"},{"startTime":1722.57,"endTime":1733.205,"body":"launch the thing is, is now unthinkable."},{"startTime":1733.665,"endTime":1735.845,"body":"Um, will do that experiment."},{"startTime":1735.845,"endTime":1739.645,"body":"It will drill into the ground and test in at least one place for life."},{"startTime":1739.655,"endTime":1745.02,"body":"Maybe we'll have to wait until samples on Mars and now bought back to Earth"},{"startTime":1745.02,"endTime":1747.525,"body":"something that people are planning to do."},{"startTime":1748.065,"endTime":1753.005,"body":"And so that we can test in earthly laboratories for signs of life."},{"startTime":1754.545,"endTime":1757.725,"body":"We can also, like we do on Venus, think about chemical signs of life."},{"startTime":1757.725,"endTime":1762.085,"body":"This is the Curiosity Rover, um, in this is just a brilliant selfie."},{"startTime":1762.465,"endTime":1764.645,"body":"Um, it's a combination of lots of images."},{"startTime":1764.675,"endTime":1767.648,"body":"It's not that somebody hopped off the rover and turned around to take a picture,"},{"startTime":1767.648,"endTime":1768.045,"body":"I promise."},{"startTime":1768.585,"endTime":1775.513,"body":"Um, curiosity, uh, which is a follow on rover following spirit and opportunity, um, has"},{"startTime":1775.513,"endTime":1778.285,"body":"detected what I'm told by Gresham."},{"startTime":1778.325,"endTime":1782.405,"body":"I should describe as burps of methane coming from underneath the surface."},{"startTime":1782.625,"endTime":1786.391,"body":"So it's happily trundling along and suddenly there's a cloud of methane, like walking behind"},{"startTime":1786.391,"endTime":1789.405,"body":"the wrong end of a cow, I suppose, or something like that."},{"startTime":1789.865,"endTime":1793.887,"body":"Um, now I'm not saying that there are small cows on Mars any more than"},{"startTime":1793.887,"endTime":1795.765,"body":"I'm saying there are penguins on Venus."},{"startTime":1796.025,"endTime":1803.412,"body":"Uh, but possibly this indicates activity, either volcanic activity on a world that we think"},{"startTime":1803.412,"endTime":1807.845,"body":"is geologically inactive or bacterial activity under the surface."},{"startTime":1808.625,"endTime":1815.365,"body":"But it's a, a, a big mystery because missions from orbit don't see the methane."},{"startTime":1816.145,"endTime":1820.626,"body":"And so there's a disagreement between what's measured on the ground and what's measured in"},{"startTime":1820.626,"endTime":1820.925,"body":"orbit."},{"startTime":1821.345,"endTime":1825.711,"body":"But it's possible that we're measuring at different types of day that the missions in"},{"startTime":1825.711,"endTime":1829.205,"body":"orbit are looking during the day, and curiosity is there at night."},{"startTime":1829.625,"endTime":1832.605,"body":"And so we need to have a think about exactly what we're measuring."},{"startTime":1832.605,"endTime":1837.165,"body":"But there is at least the possibility of a bio signature on Mars."},{"startTime":1838.785,"endTime":1844.704,"body":"Now, I mentioned there was this long hiatus between Martian missions between Viking in the"},{"startTime":1844.704,"endTime":1849.045,"body":"seventies and, um, the rovers that started in the late nineties."},{"startTime":1849.345,"endTime":1854.48,"body":"And during much of that time, we were focusing on the outer solar system, um,"},{"startTime":1854.48,"endTime":1854.822,"body":"sending two pioneer probes, pioneer 10 and 11, and then the two Voyager probes to"},{"startTime":1854.822,"endTime":1855.165,"body":"complete a grand tour of our solar systems giant planets, Jupiter, Saturn, uh, and then"},{"startTime":1855.165,"endTime":1866.805,"body":"the Ice Giants, Uranus and Neptune."},{"startTime":1867.815,"endTime":1871.845,"body":"These are, um, beautiful places to be, of course, in in their own right."},{"startTime":1872.265,"endTime":1877.902,"body":"Um, I'm a big fan of images, um, currently being sent back from Jupiter by"},{"startTime":1877.902,"endTime":1881.285,"body":"the Juno probe, which orbits in this elliptical orbit."},{"startTime":1881.285,"endTime":1885.863,"body":"And every 53 days swings close to the cloud tops of the planet and sends"},{"startTime":1885.863,"endTime":1887.085,"body":"back pictures like this."},{"startTime":1887.315,"endTime":1891.727,"body":"This is the great red spot, a storm three times the size of the earth,"},{"startTime":1891.727,"endTime":1895.845,"body":"which has been active, we think for at least 300 years and perhaps longer."},{"startTime":1896.345,"endTime":1900.205,"body":"Uh, also in this image, which I really like, um, is this spot here."},{"startTime":1900.205,"endTime":1905.155,"body":"This is an image from 2020, and this is known as Clyde's spot after an"},{"startTime":1905.155,"endTime":1906.805,"body":"amateur astronomer in South Africa."},{"startTime":1906.935,"endTime":1911.365,"body":"Clyde Foster who spotted it in his telescope before anyone else had seen it."},{"startTime":1911.385,"endTime":1917.199,"body":"We still rely on amateur astronomers to monitor the weather in the giant planets forest,"},{"startTime":1917.199,"endTime":1919.525,"body":"but it's a beautiful, beautiful image."},{"startTime":1921.065,"endTime":1925.49,"body":"We can, I I actually just me, as I'm mentioning amateur astronomers, I couldn't resist"},{"startTime":1925.49,"endTime":1926.965,"body":"showing this from Damian Peach."},{"startTime":1927.505,"endTime":1931.087,"body":"And this is with a small telescope taken from the UK just a couple of"},{"startTime":1931.087,"endTime":1931.565,"body":"weeks ago."},{"startTime":1931.945,"endTime":1935.205,"body":"But you can really see the detail on Jupiter's atmosphere."},{"startTime":1935.205,"endTime":1936.965,"body":"And what you're seeing here are cloud tops."},{"startTime":1937.345,"endTime":1943.327,"body":"You're seeing storms and bands sculpted by winds that whirl around the center of this"},{"startTime":1943.327,"endTime":1944.125,"body":"GS planet."},{"startTime":1945.145,"endTime":1947.445,"body":"We actually found out a little more about the winds recently."},{"startTime":1948.395,"endTime":1952.845,"body":"This is an image from JWST, our newest space telescope."},{"startTime":1953.305,"endTime":1958.336,"body":"Uh, and that central band, the colors are off because this is an infrared image"},{"startTime":1958.336,"endTime":1960.685,"body":"that we've tuned to slightly longer wavelengths."},{"startTime":1960.685,"endTime":1965.26,"body":"That central band is a jet stream that's moving at more than 500 kilometers an"},{"startTime":1965.26,"endTime":1965.565,"body":"hour."},{"startTime":1966.025,"endTime":1968.845,"body":"So about twice the speed of the earth's jet streams."},{"startTime":1969.225,"endTime":1974.906,"body":"And trying to understand how this complex atmosphere behaves, how it interacts, and how it"},{"startTime":1974.906,"endTime":1975.285,"body":"produces the features that we see is a good test of our understanding of climate"},{"startTime":1975.285,"endTime":1975.663,"body":"and our ability to do atmospheric modeling, uh, of the universe, of, of planets like"},{"startTime":1975.663,"endTime":1987.405,"body":"the earth elsewhere."},{"startTime":1988.545,"endTime":1994.679,"body":"But unexpectedly, the missions to Jupiter and to Saturn, um, became part of this grand"},{"startTime":1994.679,"endTime":2000.405,"body":"story of the creation of life or the search for life in the universe."},{"startTime":2001.465,"endTime":2006.25,"body":"Not on the planets themselves, though Carl Sagan speculated about hydrogen breathing, jellyfish and whales"},{"startTime":2006.25,"endTime":2007.845,"body":"in the atmosphere of Jupiter."},{"startTime":2007.845,"endTime":2009.325,"body":"So if you want to go that far, you can."},{"startTime":2009.705,"endTime":2015.301,"body":"Uh, but actually on the moons, which turn out to be fascinating places, the red"},{"startTime":2015.301,"endTime":2019.405,"body":"stripe at the top and bottom of this image is real."},{"startTime":2019.655,"endTime":2022.645,"body":"Those are the northern and southern lights on Jupiter."},{"startTime":2022.985,"endTime":2028.54,"body":"The Aurora, uh, like those that we see on the, on the earth, they're caused"},{"startTime":2028.54,"endTime":2033.725,"body":"and they're spectacular in Jupiter because of the presence nearby of the moon io."},{"startTime":2034.115,"endTime":2038.045,"body":"This is a Voyager image, the first one taken of the moon."},{"startTime":2038.365,"endTime":2038.485,"body":"Actually."},{"startTime":2038.795,"endTime":2042.816,"body":"This is a moon that was discovered by Galileo, but studied close up by the"},{"startTime":2042.816,"endTime":2043.085,"body":"spacecraft."},{"startTime":2043.425,"endTime":2045.965,"body":"And you could see there's that plume off to the left there."},{"startTime":2045.965,"endTime":2047.685,"body":"That's a volcano, that's erupting."},{"startTime":2048.105,"endTime":2050.245,"body":"Um, it's actually a, a volcano called Locky."},{"startTime":2050.385,"endTime":2052.405,"body":"And in the middle you've got Pele as well."},{"startTime":2053.255,"endTime":2055.965,"body":"These are spectacular, uh, features."},{"startTime":2055.965,"endTime":2058.445,"body":"This is io seen by the Galileo spacecraft."},{"startTime":2058.905,"endTime":2061.844,"body":"Um, and the flare that's in the middle here."},{"startTime":2062.175,"endTime":2065.085,"body":"Prometheus seems to have been erupting for at least 30 years."},{"startTime":2065.264,"endTime":2067.844,"body":"Io is the most volcanic place in the solar system."},{"startTime":2067.844,"endTime":2073.244,"body":"And the material that it throws up, um, end up caught by Jupiter's magnetic field,"},{"startTime":2073.244,"endTime":2078.284,"body":"hit the atmosphere and create what must be spectacular displays of the Northern lights."},{"startTime":2080.065,"endTime":2083.925,"body":"The other big moons of Jupiter have a different story to tell."},{"startTime":2084.435,"endTime":2089.205,"body":"This is Europa, a recent image from Juneau, um, in true color."},{"startTime":2089.505,"endTime":2092.885,"body":"So this is what it would look like to be an orbit around Europa."},{"startTime":2093.225,"endTime":2098.405,"body":"And you can see that it has this smooth, icy surface."},{"startTime":2098.915,"endTime":2100.125,"body":"It's in fact water, ice."},{"startTime":2100.745,"endTime":2105.456,"body":"Um, and you can see that there are very few craters on this surface, and"},{"startTime":2105.456,"endTime":2106.085,"body":"that's important."},{"startTime":2106.585,"endTime":2112.085,"body":"The number of craters on a solar system surface tells you how old it is."},{"startTime":2112.825,"endTime":2116.325,"body":"The more craters you've got, the more meteorites have hit you, the more meteorites have"},{"startTime":2116.325,"endTime":2119.125,"body":"hit you, the longer you've been sitting there out there in space."},{"startTime":2119.705,"endTime":2124.005,"body":"And so the fact that this is smooth, tell us this is a fresh surface"},{"startTime":2124.005,"endTime":2125.725,"body":"that gets resurfaced every so often."},{"startTime":2126.635,"endTime":2131.421,"body":"Results from the last couple of weeks from JWST tell us that that surface, this"},{"startTime":2131.421,"endTime":2131.74,"body":"water, ice has salt in it, and a bit of carbon dioxide frozen onto the"},{"startTime":2131.74,"endTime":2137.165,"body":"surface as well."},{"startTime":2137.825,"endTime":2143.381,"body":"So wherever this water is coming from and freezing onto the surface, it has a"},{"startTime":2143.381,"endTime":2147.085,"body":"salty component and it's also got some carbon in it."},{"startTime":2147.085,"endTime":2150.365,"body":"We're getting to the schnapps that we need to create life."},{"startTime":2151.865,"endTime":2158.855,"body":"Our assumption is that this is a ice shell with a liquid water core, so"},{"startTime":2158.855,"endTime":2159.321,"body":"that within this moon there's an ocean, a salty ocean that we can imagine as"},{"startTime":2159.321,"endTime":2167.245,"body":"a potential habitat."},{"startTime":2167.955,"endTime":2171.526,"body":"This turns out to be a common way of building things in the Alto solar"},{"startTime":2171.526,"endTime":2171.765,"body":"system."},{"startTime":2171.785,"endTime":2176.54,"body":"The next moon out, OMI, perhaps even Callisto, the next big moon have such oceans"},{"startTime":2176.54,"endTime":2178.125,"body":"probes are on their way."},{"startTime":2178.125,"endTime":2183.172,"body":"There's a European probe called juice, which is on its way to explore gade swinging"},{"startTime":2183.172,"endTime":2183.845,"body":"past Europa."},{"startTime":2183.845,"endTime":2189.332,"body":"There's an American probe called Europa Clipper that will launch next year, arriving in 2030"},{"startTime":2189.332,"endTime":2189.698,"body":"and 2031 to explore these moons, um, Triton, Neptune's largest moon may be another one"},{"startTime":2189.698,"endTime":2190.064,"body":"of these icy worlds with an ocean inside even Pluto, which by the way definitely"},{"startTime":2190.064,"endTime":2201.405,"body":"isn't a planet."},{"startTime":2201.785,"endTime":2203.405,"body":"Um, and we can talk about that later."},{"startTime":2203.945,"endTime":2208.045,"body":"Um, Pluto may have an ICA shell and an ocean within it."},{"startTime":2208.345,"endTime":2214.925,"body":"So it's not too farfetched to imagine Pluto as a habitat for, uh, life."},{"startTime":2215.415,"endTime":2220.845,"body":"These places may be the most common habitats for life in the galaxy."},{"startTime":2220.845,"endTime":2225.756,"body":"So the idea of living on the surface of a planet, we may be the"},{"startTime":2225.756,"endTime":2226.084,"body":"exceptions, and that if life is common, most of it may live in a ocean"},{"startTime":2226.084,"endTime":2234.925,"body":"surrounded by an icy roof cut off from the rest of the system."},{"startTime":2235.625,"endTime":2239.242,"body":"And it's kind of interesting to think about what life might be like in such"},{"startTime":2239.242,"endTime":2239.725,"body":"a world."},{"startTime":2239.815,"endTime":2242.045,"body":"You'd have no knowledge of the rest of the universe."},{"startTime":2242.895,"endTime":2246.945,"body":"You'd have no, if you managed to reach int intelligence, I dunno, intelligent dolphin in"},{"startTime":2246.945,"endTime":2249.645,"body":"the middle of Europa or something, or squid or whatever."},{"startTime":2250.065,"endTime":2253.153,"body":"Uh, maybe if you were good at physics, you deduced that you were in orbit"},{"startTime":2253.153,"endTime":2253.565,"body":"around something."},{"startTime":2254.305,"endTime":2258.975,"body":"But I think dolphin astronauts emerging, having melted their way through the ice into the"},{"startTime":2258.975,"endTime":2259.286,"body":"grandeur of our universe, are gonna have a, a shock, and b are gonna be"},{"startTime":2259.286,"endTime":2268.005,"body":"very surprised to discover that life can exist on the surface of a planet."},{"startTime":2268.395,"endTime":2273.703,"body":"This close to the sun and this exposed to the rest of the, uh, uh,"},{"startTime":2273.703,"endTime":2274.765,"body":"of the universe."},{"startTime":2275.575,"endTime":2281.167,"body":"There is a place though, where we might get direct access to, uh, an ocean"},{"startTime":2281.167,"endTime":2283.405,"body":"from one of these water worlds."},{"startTime":2283.665,"endTime":2289.048,"body":"And it's in a moon of Saturn called Enceladus, which was known to be a"},{"startTime":2289.048,"endTime":2290.125,"body":"hugely reflective thing."},{"startTime":2290.125,"endTime":2293.475,"body":"This is it in the, in the near, in the front here with Titan, more"},{"startTime":2293.475,"endTime":2295.485,"body":"of which in a sec, lurking in the background."},{"startTime":2296.765,"endTime":2301.565,"body":"Enceladus was this small moon known to be made of water, ice imaged in passing"},{"startTime":2301.565,"endTime":2302.845,"body":"by the Voyager spacecraft."},{"startTime":2303.185,"endTime":2307.245,"body":"Um, it's about the size of the British Isles, nothing more than that."},{"startTime":2307.585,"endTime":2313.135,"body":"But when, when the Cassini probe went there and took closeup images, um, they showed"},{"startTime":2313.135,"endTime":2314.245,"body":"these strange features."},{"startTime":2314.245,"endTime":2315.605,"body":"They're known as tiger stripes."},{"startTime":2315.605,"endTime":2320.325,"body":"They're sort of like glacial rifts scratched across the southern half of this moon."},{"startTime":2320.325,"endTime":2321.645,"body":"And again, no craters."},{"startTime":2322.025,"endTime":2323.725,"body":"So this is a fresh surface."},{"startTime":2324.745,"endTime":2329.374,"body":"But then s attracted the intention of the mission planners when early on Cassini, having"},{"startTime":2329.374,"endTime":2329.683,"body":"traveled for many years to get to Saturn, one of the first things it did"},{"startTime":2329.683,"endTime":2336.165,"body":"by coincidence was fly near this moon."},{"startTime":2337.105,"endTime":2338.485,"body":"The cameras weren't turned on."},{"startTime":2338.955,"endTime":2343.8,"body":"Most of the instruments weren't paying attention, but there was a group led by Michelle"},{"startTime":2343.8,"endTime":2348.645,"body":"Dockerty at Imperial College London, um, who were interested in magnetic fields in the system."},{"startTime":2348.645,"endTime":2353.121,"body":"They have this long magnetometer, a boom that sticks out from the spacecraft and as"},{"startTime":2353.121,"endTime":2356.405,"body":"it flies round, it records the strength of the magnetic field."},{"startTime":2356.745,"endTime":2359.045,"body":"And they were interested in, in doing all sorts of things with it."},{"startTime":2359.045,"endTime":2360.885,"body":"But they thought Enceladus would be a good test."},{"startTime":2360.885,"endTime":2364.725,"body":"They wanted to fly past Indus and they expected to see no change whatsoever."},{"startTime":2366.085,"endTime":2371.581,"body":"Enceladus is too small to have a magnetic field it should be in at they"},{"startTime":2371.581,"endTime":2375.245,"body":"flew past, their instrument worked fine and they're excellent scientists."},{"startTime":2375.245,"endTime":2379.109,"body":"So they looked at the data and discovered that something had changed the magnetic field"},{"startTime":2379.109,"endTime":2381.685,"body":"as they flew past, they didn't know what it was."},{"startTime":2382.075,"endTime":2386.845,"body":"They persuaded the team to fly back closer with cameras turned on."},{"startTime":2387.585,"endTime":2393.701,"body":"And they essentially flew their spacecraft through fountains of water that are shooting out from"},{"startTime":2393.701,"endTime":2394.925,"body":"the South Pole."},{"startTime":2394.925,"endTime":2399.285,"body":"This is a real image of Enceladus taken on a subsequent pass."},{"startTime":2400.145,"endTime":2402.285,"body":"Um, this is a water world."},{"startTime":2402.545,"endTime":2407.195,"body":"It somehow has a liquid ocean, which we know is salty because we've flown through"},{"startTime":2407.195,"endTime":2410.605,"body":"it, which means that there's an ocean floor down there somewhere."},{"startTime":2411.305,"endTime":2416.085,"body":"And we think that life on earth maybe got started on the deep ocean floor."},{"startTime":2416.145,"endTime":2419.485,"body":"So this is a habitat very much like the one that we came from."},{"startTime":2420.105,"endTime":2421.805,"body":"We also think that it might be long lived."},{"startTime":2423.265,"endTime":2430.005,"body":"The I water that escapes from Enceladus forms a tenuous ring around Saturn."},{"startTime":2430.355,"endTime":2431.485,"body":"It's called the E Ring."},{"startTime":2431.985,"endTime":2437.045,"body":"Um, and this is Enceladus, the bright spot within the faint earring."},{"startTime":2437.305,"endTime":2441.055,"body":"And there's so much material there that we know that Enceladus has been active for"},{"startTime":2441.055,"endTime":2441.805,"body":"millions of years."},{"startTime":2442.625,"endTime":2446.565,"body":"And so that means there's been an ocean there for at least millions of years."},{"startTime":2447.265,"endTime":2454.671,"body":"And so we have this idea that Enceladus may be the most likely habitat for"},{"startTime":2454.671,"endTime":2455.165,"body":"life."},{"startTime":2455.305,"endTime":2459.283,"body":"And it's a place where if we go back with another spacecraft, you could take"},{"startTime":2459.283,"endTime":2461.405,"body":"a sample just by flying through the fountains."},{"startTime":2461.405,"endTime":2462.685,"body":"We don't need to drill through the ice."},{"startTime":2463.105,"endTime":2465.285,"body":"We don't need to invent some elaborate technology."},{"startTime":2465.585,"endTime":2471.158,"body":"We can go and test whether there is indeed life in this moon, um, just"},{"startTime":2471.158,"endTime":2472.645,"body":"by flying past it."},{"startTime":2472.865,"endTime":2477.205,"body":"And of course a visit back to the Cian system would be worth doing anyway."},{"startTime":2478.185,"endTime":2486.143,"body":"Saturn is, I think, indisputably the most beautiful of planets with the, uh, ring system"},{"startTime":2486.143,"endTime":2487.205,"body":"around it."},{"startTime":2487.215,"endTime":2492.811,"body":"These millions, if not billions of IC particles sculpted into this thin set of rings"},{"startTime":2492.811,"endTime":2493.184,"body":"by the gravity of the planet and by the activity of shepherd moons, tiny moons,"},{"startTime":2493.184,"endTime":2502.885,"body":"which orbit around with the ring particles and keep them in place."},{"startTime":2503.705,"endTime":2508.17,"body":"The whole set of rings is about 20 meters thick, so much thinner than uh,"},{"startTime":2508.17,"endTime":2511.445,"body":"many of the buildings in the city around us at all."},{"startTime":2511.905,"endTime":2515.405,"body":"Uh, and yet they provide this amazing, beautiful site."},{"startTime":2516.105,"endTime":2521.068,"body":"But the other reason to go back to Saturn isn't the planet itself, though it's"},{"startTime":2521.068,"endTime":2521.399,"body":"fascinating and it's not the rings, even though studying them could teach us more about"},{"startTime":2521.399,"endTime":2521.729,"body":"physics and dynamics, it's to go to a place called Titan, which I think is"},{"startTime":2521.729,"endTime":2534.965,"body":"one of the most mysterious and interesting places anywhere in the cosmos."},{"startTime":2536.135,"endTime":2540.245,"body":"Titan at first glance doesn't look like much here."},{"startTime":2540.245,"endTime":2543.605,"body":"It is seen from the Voyager probes and it's an orange ball."},{"startTime":2544.185,"endTime":2549.005,"body":"And it looks like this because it has an atmosphere."},{"startTime":2549.155,"endTime":2553.165,"body":"It's the only moon in the solar system, which has a thick atmosphere."},{"startTime":2553.835,"endTime":2559.731,"body":"It's an atmosphere like the Earth that's mostly nitrogen, but it has hydrocarbon haze in"},{"startTime":2559.731,"endTime":2560.125,"body":"it."},{"startTime":2560.125,"endTime":2561.365,"body":"That's why we can't see through it."},{"startTime":2561.365,"endTime":2567.327,"body":"You have to tune into the infrared to be able to see through this hazy"},{"startTime":2567.327,"endTime":2567.725,"body":"atmosphere."},{"startTime":2567.995,"endTime":2568.925,"body":"Cassini could do that."},{"startTime":2568.945,"endTime":2575.165,"body":"Here's an early picture of the surface of Titan seen darkly, uh, through the haze."},{"startTime":2575.165,"endTime":2578.405,"body":"You can see there are some indistinct features on the surface."},{"startTime":2579.145,"endTime":2583.856,"body":"But to find out what these were, we needed to send a probe down onto"},{"startTime":2583.856,"endTime":2584.485,"body":"the surface."},{"startTime":2585.425,"endTime":2591.197,"body":"And Cassini dropped off a European par called Hogans, which traveled down through the atmosphere"},{"startTime":2591.197,"endTime":2595.045,"body":"and provided us with our first glimpse of the surface."},{"startTime":2595.225,"endTime":2599.982,"body":"So this is real footage sped up from that descent from the Hogans probe sent"},{"startTime":2599.982,"endTime":2601.885,"body":"back to Earth from the surface."},{"startTime":2602.745,"endTime":2607.51,"body":"And so first of all, you go through the haze, but as we get deeper"},{"startTime":2607.51,"endTime":2611.005,"body":"in, you can begin to see features emerging on the landscape."},{"startTime":2611.705,"endTime":2616.486,"body":"He said convincingly, uh, it takes a little while to, to fall down the planet's"},{"startTime":2616.486,"endTime":2616.805,"body":"gravity."},{"startTime":2616.905,"endTime":2620.273,"body":"Uh, the moon's gravity is weak, but you go, you can begin to see these"},{"startTime":2620.273,"endTime":2621.845,"body":"are sort of look like river valleys."},{"startTime":2622.145,"endTime":2623.525,"body":"That's exactly what they are."},{"startTime":2624.135,"endTime":2629.357,"body":"Titan is a place where it rains methane in great big methane raindrops, the size"},{"startTime":2629.357,"endTime":2629.705,"body":"of lawn tennis balls that fall slowly enough that you could dodge them if you"},{"startTime":2629.705,"endTime":2637.365,"body":"were there, uh, because of the weak gravity."},{"startTime":2638.895,"endTime":2642.965,"body":"Titan is a place where instead of a water cycle, it has a hydrocarbon cycle."},{"startTime":2643.545,"endTime":2644.885,"body":"So these rivers are long lived."},{"startTime":2644.955,"endTime":2650.626,"body":"They feed into oceans and lakes, um, which have all sorts of exotic things going"},{"startTime":2650.626,"endTime":2651.005,"body":"on."},{"startTime":2651.005,"endTime":2656.79,"body":"There was a period where Cassini was seeing from orbit, um, things called magic islands"},{"startTime":2656.79,"endTime":2661.805,"body":"that seemed to appear and disappear within the, uh, middle of these lakes."},{"startTime":2662.185,"endTime":2666.001,"body":"It turns out those are places where bubbles are coming up from chemistry that's happening"},{"startTime":2666.001,"endTime":2666.765,"body":"under the surface."},{"startTime":2667.345,"endTime":2672.733,"body":"And Cassini was detecting a raft of bubbles that would then slowly disappear as the"},{"startTime":2672.733,"endTime":2676.685,"body":"seasons change on this world, Hogans is still coming down here."},{"startTime":2677.105,"endTime":2678.085,"body":"Uh, there was no control."},{"startTime":2678.085,"endTime":2681.685,"body":"They just pointed it at Titan and and hoped it would land somewhere interesting."},{"startTime":2682.025,"endTime":2686.347,"body":"It was equipped to land on liquid or on land, and in fact it came"},{"startTime":2686.347,"endTime":2688.365,"body":"down and bounced onto a frozen surface."},{"startTime":2689.145,"endTime":2692.325,"body":"Um, and I might try and speed this up a bit."},{"startTime":2693.295,"endTime":2694.245,"body":"Let's go forwards."},{"startTime":2694.625,"endTime":2699.565,"body":"Um, 'cause I just wanna show you the landing site, which has these frozen pebbles."},{"startTime":2699.565,"endTime":2703.925,"body":"So these are probably, um, carbon dioxide or even hydrocarbon pebbles."},{"startTime":2704.465,"endTime":2710.78,"body":"Um, there's a brilliant experiment where Cassini had a penetrometer, something that stuck out from"},{"startTime":2710.78,"endTime":2712.885,"body":"the end of the probe."},{"startTime":2712.885,"endTime":2716.278,"body":"And the idea was that when it hit the surface, it could detect how hard"},{"startTime":2716.278,"endTime":2719.445,"body":"the surface was so that we could work out what it was made of."},{"startTime":2720.515,"endTime":2721.765,"body":"They got quite a strange signal."},{"startTime":2721.765,"endTime":2724.765,"body":"They got a sudden jolt and then a second softer one."},{"startTime":2725.905,"endTime":2728.565,"body":"Um, and they didn't really understand why this had happened."},{"startTime":2728.825,"endTime":2733.52,"body":"The principal investigator, John Zaki from the Open University, um, in the press conference the"},{"startTime":2733.52,"endTime":2733.833,"body":"next morning, having not slapped, um, decided to tell the world that this felt like"},{"startTime":2733.833,"endTime":2742.285,"body":"creme brulee, \u003claugh\u003e 'cause you had a crust and then a soft landing."},{"startTime":2742.785,"endTime":2747.605,"body":"Um, rumors that John ended up dropping stuff into creme brulee in his lab."},{"startTime":2748.025,"endTime":2749.445,"body":"Uh, I can't confirm or deny."},{"startTime":2749.445,"endTime":2750.485,"body":"It's less like creme brulee."},{"startTime":2750.485,"endTime":2754.021,"body":"What actually happened was they hit one of these boulders, cracked it, and then slid"},{"startTime":2754.021,"endTime":2754.965,"body":"off onto the surface."},{"startTime":2755.975,"endTime":2759.205,"body":"Titan is an amazing place in these lakes."},{"startTime":2760.745,"endTime":2767.348,"body":"Chemistry is happening and the scientists, Jonathan Lein, suggests that in those lakes, there may"},{"startTime":2767.348,"endTime":2767.788,"body":"be something right on the edge of being life repeated patterns of chemistry, of complex"},{"startTime":2767.788,"endTime":2768.228,"body":"chemistry that are self-perpetuating, but don't come anywhere near even the simplest virus or bacteria"},{"startTime":2768.228,"endTime":2781.875,"body":"here on earth."},{"startTime":2781.935,"endTime":2786.291,"body":"So Titan may be an edge case with lots to tell us, and I'm really"},{"startTime":2786.291,"endTime":2789.195,"body":"excited that we're going back in a few years time."},{"startTime":2790.135,"endTime":2796.155,"body":"The Dragonfly mission, which is a a little octocopter, will land on Titan."},{"startTime":2796.895,"endTime":2801.037,"body":"And the idea is that it will land in different places, study them for a"},{"startTime":2801.037,"endTime":2804.075,"body":"couple of weeks, and then fly off and explore somewhere else."},{"startTime":2804.465,"endTime":2809.035,"body":"It's a completely new way of exploring a celestial body and it looks really cool."},{"startTime":2809.535,"endTime":2812.515,"body":"Um, so I'm very excited by Dragonfly."},{"startTime":2813.875,"endTime":2818.586,"body":"I want to end my tour of some of the marvels of the solar system"},{"startTime":2818.586,"endTime":2822.355,"body":"by coming back to Mars because it's easy to tell this story."},{"startTime":2823.055,"endTime":2825.515,"body":"And NASA and Issa and the rest of us do this all the time."},{"startTime":2825.905,"endTime":2828.075,"body":"It's easy to tell this story as a search for life."},{"startTime":2828.145,"endTime":2829.435,"body":"It's a search for habitats."},{"startTime":2829.435,"endTime":2835.712,"body":"It's a search for company out in the solar system and discovering life elsewhere, especially"},{"startTime":2835.712,"endTime":2836.131,"body":"if we could prove that it had independently would be one of the greatest scientific"},{"startTime":2836.131,"endTime":2843.665,"body":"discoveries of all time."},{"startTime":2843.965,"endTime":2849.546,"body":"But I keep thinking back to an interview I did with Steve Squires, who is"},{"startTime":2849.546,"endTime":2849.918,"body":"the principal investigator, the person in charge of the Spirit and Opportunity Rovers that I"},{"startTime":2849.918,"endTime":2856.245,"body":"talked about earlier."},{"startTime":2856.275,"endTime":2860.645,"body":"This is a, an image of spirit looking back to a place called Husband Hill."},{"startTime":2860.945,"endTime":2863.525,"body":"And you can see the tracks that this thing left on the surface."},{"startTime":2864.385,"endTime":2869.245,"body":"And I interviewed Steve about two years into his 90 day mission on Mars."},{"startTime":2870.105,"endTime":2873.087,"body":"And to give you a clue as to how he was feeling, I said, how's"},{"startTime":2873.087,"endTime":2873.485,"body":"it going?"},{"startTime":2873.505,"endTime":2877.535,"body":"He said, we're tired, \u003claugh\u003e, they were still at that point living on Mars time,"},{"startTime":2877.535,"endTime":2879.685,"body":"which is 24 and a half hour days."},{"startTime":2879.825,"endTime":2883.89,"body":"So they were slipping by half an hour compared to their friends, neighbors and families"},{"startTime":2883.89,"endTime":2885.245,"body":"again and again and again."},{"startTime":2885.245,"endTime":2888.645,"body":"As they went through the months, they eventually decided that they should let the rovers"},{"startTime":2888.645,"endTime":2891.365,"body":"have a rest occasionally and they should stick to to Earth time."},{"startTime":2891.865,"endTime":2896.491,"body":"Um, but at this point they discovered, as I told you, that water had once"},{"startTime":2896.491,"endTime":2897.725,"body":"been common on Mars."},{"startTime":2899.265,"endTime":2903.858,"body":"But they'd found at that point in the place where spirit was, that it was"},{"startTime":2903.858,"endTime":2904.165,"body":"acidic."},{"startTime":2904.625,"endTime":2908.312,"body":"To go back to the beginning, it was sort of about the same acidity as"},{"startTime":2908.312,"endTime":2908.557,"body":"a lab bench sulfuric acid that you would've used in school or in a chemistry"},{"startTime":2908.557,"endTime":2912.245,"body":"experiment."},{"startTime":2912.745,"endTime":2916.49,"body":"And so I just said casually, I said, oh, well that's disappointing because I was"},{"startTime":2916.49,"endTime":2916.739,"body":"thinking about this story of trying to find places where our kind of life can"},{"startTime":2916.739,"endTime":2920.485,"body":"exist."},{"startTime":2921.145,"endTime":2924.805,"body":"And Steve didn't quite lose his rag, but he got pretty annoyed with me."},{"startTime":2924.805,"endTime":2930.876,"body":"And I remember him saying, the thing is, if you want to study an earth-like"},{"startTime":2930.876,"endTime":2933.305,"body":"world, you can stay on earth."},{"startTime":2934.125,"endTime":2935.225,"body":"We go to Mars."},{"startTime":2935.245,"endTime":2938.625,"body":"He told me because it's like Mars, because it's not like earth."},{"startTime":2938.625,"endTime":2943.888,"body":"Because if we want to understand our solar system and our cosmos, we have to"},{"startTime":2943.888,"endTime":2946.345,"body":"go to places that are very different."},{"startTime":2946.405,"endTime":2951.935,"body":"And the solar system is full of worlds that surprise us from small asteroids like,"},{"startTime":2951.935,"endTime":2952.304,"body":"uh, Benu visited by AX Rex just in the last few years with a sample"},{"startTime":2952.304,"endTime":2960.785,"body":"return to earth just a month or so ago."},{"startTime":2961.085,"endTime":2965.793,"body":"The swirling clouds in Juno's images of Jupiter are as beautiful as looking at Saturn's"},{"startTime":2965.793,"endTime":2966.107,"body":"rings through a telescope from up close the rings and that dance of billions of"},{"startTime":2966.107,"endTime":2972.385,"body":"particles as much to teach us."},{"startTime":2972.645,"endTime":2977.249,"body":"And Uranus and Neptune are the two planets which are closest to the most common"},{"startTime":2977.249,"endTime":2979.705,"body":"part type of planet in the Milky Way."},{"startTime":2979.705,"endTime":2982.145,"body":"And we've only seen them once from closeup."},{"startTime":2982.925,"endTime":2988.763,"body":"And if Pluto though it's not a planet was the most interesting thing we'd seen"},{"startTime":2988.763,"endTime":2989.152,"body":"when the New Horizons probe flew past and showed us mountains of water, ice, heart-shaped"},{"startTime":2989.152,"endTime":2998.105,"body":"features of churning material and all sorts of mysteries."},{"startTime":2998.105,"endTime":3002.067,"body":"Then what are Eris and Makki and the other hundreds of worlds of the co"},{"startTime":3002.067,"endTime":3002.331,"body":"about the un outer solar system going to be like, the conclusion, I think is"},{"startTime":3002.331,"endTime":3002.595,"body":"that the solar system is full of marvels and it doesn't matter that much if"},{"startTime":3002.595,"endTime":3012.105,"body":"we don't have anyone to share them with."},{"startTime":3012.235,"endTime":3012.905,"body":"Thank you very much,"},{"startTime":3023.795,"endTime":3024.145,"body":"Chris."},{"startTime":3024.145,"endTime":3024.545,"body":"Thank you."},{"startTime":3024.545,"endTime":3026.305,"body":"That was absolutely fascinating."},{"startTime":3026.505,"endTime":3028.845,"body":"I certainly felt that I learned an awful lot there."},{"startTime":3029.015,"endTime":3030.605,"body":"We've got time for a few questions."},{"startTime":3030.785,"endTime":3031.805,"body":"I'm gonna start over here."},{"startTime":3031.805,"endTime":3034.831,"body":"And the first one is a nice easy one to get start you off with"},{"startTime":3034.831,"endTime":3036.445,"body":"and it picks up on that final point."},{"startTime":3037.025,"endTime":3041.003,"body":"How does this kind of research that you're doing challenge some of our normative or"},{"startTime":3041.003,"endTime":3043.125,"body":"our conventional concepts of life, do you think?"},{"startTime":3043.475,"endTime":3043.765,"body":"Well,"},{"startTime":3043.765,"endTime":3048.385,"body":"I, I think throughout we've been talking as if we need the same conditions that"},{"startTime":3048.385,"endTime":3049.925,"body":"we have here on earth."},{"startTime":3050.745,"endTime":3055.384,"body":"Um, and so, and when we talk about biosignatures and looking for places where life"},{"startTime":3055.384,"endTime":3059.405,"body":"might exist, we implicitly mean places where our kind of life might exist."},{"startTime":3059.425,"endTime":3065.17,"body":"Now, it's possible that life can tolerate all sorts of things on earth, life tolerates"},{"startTime":3065.17,"endTime":3067.085,"body":"all, all sort of things."},{"startTime":3067.565,"endTime":3072.085,"body":"I think the biggest mystery of all is how life got started here."},{"startTime":3072.585,"endTime":3076.379,"body":"And we don't have any real idea of what conditions you need for life to"},{"startTime":3076.379,"endTime":3076.885,"body":"get started."},{"startTime":3076.905,"endTime":3080.205,"body":"We think once it gets started, famously it finds a way, right?"},{"startTime":3080.545,"endTime":3085.179,"body":"So, so once life gets started, it could tolerate all sorts of things, but this"},{"startTime":3085.179,"endTime":3085.488,"body":"is an exploration that tells us about whether and how life will have got started,"},{"startTime":3085.488,"endTime":3092.285,"body":"thus how common it is in the cosmos."},{"startTime":3092.745,"endTime":3095.525,"body":"Um, but I almost feel like the astronomers have done our job."},{"startTime":3095.545,"endTime":3099.325,"body":"We found this range of places now the biologists need to tell us which ones"},{"startTime":3099.325,"endTime":3101.845,"body":"life can form in and then we'll go and check."},{"startTime":3102.785,"endTime":3106.913,"body":"So there's still, I mean obviously we're moving away from those dreams of humanoid aliens"},{"startTime":3106.913,"endTime":3108.565,"body":"and you know, star Trek stuff."},{"startTime":3108.595,"endTime":3108.885,"body":"Yeah."},{"startTime":3108.885,"endTime":3109.885,"body":"At least in the solar system."},{"startTime":3109.955,"endTime":3110.245,"body":"Yeah."},{"startTime":3110.545,"endTime":3114.273,"body":"So it's maybe sort of broadening our, our kind of concept to our inquiry about"},{"startTime":3114.273,"endTime":3115.765,"body":"what life is or could be."},{"startTime":3115.865,"endTime":3116.365,"body":"That's true."},{"startTime":3116.445,"endTime":3120.468,"body":"I think it also broadens our sense of, yeah, I think it's, it's interesting look"},{"startTime":3120.468,"endTime":3120.736,"body":"at those pictures of Mars, which, you know, I do often if, if you're lucky"},{"startTime":3120.736,"endTime":3121.005,"body":"enough, if you go online at the right time, you could be the first person"},{"startTime":3121.005,"endTime":3121.273,"body":"to see a new image of Mars, um, as it comes down off the spacecraft,"},{"startTime":3121.273,"endTime":3134.685,"body":"even before the team that built the spacecraft."},{"startTime":3135.105,"endTime":3138.78,"body":"But if you look at, I dunno, Victoria Crater or something, something like that, um,"},{"startTime":3138.78,"endTime":3141.965,"body":"it's very hard to me not to have a human response to this."},{"startTime":3141.965,"endTime":3145.47,"body":"Like, I, I I think it partly the rovers have cameras that are about this"},{"startTime":3145.47,"endTime":3146.405,"body":"high off the ground."},{"startTime":3146.985,"endTime":3151.445,"body":"And so my head translates really easily to me standing there planning a walk."},{"startTime":3151.785,"endTime":3155.944,"body":"So I think it, it challenges us to imagine being at, in these places and"},{"startTime":3155.944,"endTime":3157.885,"body":"how we'd interact with them as well."},{"startTime":3157.905,"endTime":3158.325,"body":"Denise"},{"startTime":3158.325,"endTime":3162.125,"body":"Would like to know, is it correct that Jupiter and Saturn were closer to the"},{"startTime":3162.125,"endTime":3163.645,"body":"sun in an earlier solar system?"},{"startTime":3163.665,"endTime":3166.205,"body":"And if so, what caused them to change Orbits?"},{"startTime":3166.235,"endTime":3167.445,"body":"That is in my next lecture."},{"startTime":3167.625,"endTime":3169.885,"body":"Ah, so yeah, yeah, yeah, yeah, yeah."},{"startTime":3169.945,"endTime":3170.525,"body":"So we'll come back."},{"startTime":3170.625,"endTime":3174.682,"body":"But, but yes, so, so the spoiler is the, the solar system is not the"},{"startTime":3174.682,"endTime":3175.765,"body":"stable place it seems."},{"startTime":3176.345,"endTime":3179.861,"body":"Um, and the interaction between the planets can do dramatic things and we, we have"},{"startTime":3179.861,"endTime":3180.565,"body":"evidence of that."},{"startTime":3180.625,"endTime":3183.977,"body":"So tune in in January to, I'm gonna look straight down the camera, tune in"},{"startTime":3183.977,"endTime":3185.765,"body":"in January to find out more about that."},{"startTime":3186.755,"endTime":3188.005,"body":"That would be a lovely link."},{"startTime":3188.005,"endTime":3191.633,"body":"But actually you've still got a few more minutes, so if there's any questions from"},{"startTime":3191.633,"endTime":3193.085,"body":"the floor, please raise a hand."},{"startTime":3193.595,"endTime":3198.509,"body":"What I want to ask you is, do all the planets have magnetic fields or"},{"startTime":3198.509,"endTime":3199.165,"body":"they don't?"},{"startTime":3199.785,"endTime":3204.485,"body":"And also the other thing is that, uh, a planet like Jupiter takes a long"},{"startTime":3204.485,"endTime":3206.365,"body":"time to go around the sun."},{"startTime":3207.115,"endTime":3209.365,"body":"Does it, do they also spin round?"},{"startTime":3209.905,"endTime":3211.365,"body":"Yes, as we do on earth?"},{"startTime":3211.585,"endTime":3213.885,"body":"So yes, they all spin though."},{"startTime":3213.885,"endTime":3215.125,"body":"There are a couple of mysteries."},{"startTime":3215.485,"endTime":3216.405,"body":"Uranus rolls."},{"startTime":3216.985,"endTime":3219.605,"body":"So its poles are more or less pointed towards the sun."},{"startTime":3219.865,"endTime":3224.365,"body":"And so it rolls round Venus as, as maybe, you know, spins very slowly."},{"startTime":3224.905,"endTime":3229.36,"body":"So a day on Venus is longer than a year, um, which is gonna make"},{"startTime":3229.36,"endTime":3230.845,"body":"the news calendars very difficult."},{"startTime":3231.185,"endTime":3232.925,"body":"But we also don't understand why that should be."},{"startTime":3232.925,"endTime":3237.477,"body":"So, so there's a generic thing in planetary astronomy and apologies to planetary astronomers who"},{"startTime":3237.477,"endTime":3238.085,"body":"are watching."},{"startTime":3238.185,"endTime":3241.47,"body":"If they can't explain anything, then they tend to just say there was a collision"},{"startTime":3241.47,"endTime":3242.565,"body":"in the early solar system."},{"startTime":3242.905,"endTime":3247.405,"body":"So both Uranus and Venus', strange behavior has been explained by collisions, magnetic fields, all"},{"startTime":3247.405,"endTime":3249.205,"body":"the, all the giant planets do."},{"startTime":3249.625,"endTime":3251.645,"body":"Um, but not all the rocky planets."},{"startTime":3251.645,"endTime":3252.845,"body":"So Venus has a weak field."},{"startTime":3252.845,"endTime":3253.925,"body":"Mercury doesn't have one."},{"startTime":3254.065,"endTime":3258.352,"body":"And we don't understand why one of the big mysteries of planetary science is why"},{"startTime":3258.352,"endTime":3260.925,"body":"the earth has a field and, and others don't."},{"startTime":3261.265,"endTime":3264.365,"body":"It may be linked to the fact Venus doesn't have plate tectonics."},{"startTime":3265.345,"endTime":3270.322,"body":"So our continent shift and change that doesn't happen on Venus, perhaps because the water"},{"startTime":3270.322,"endTime":3272.645,"body":"is boiled away and there's no lubricant."},{"startTime":3272.865,"endTime":3277.002,"body":"But there's, these are very different planets, even though on the surface if all you"},{"startTime":3277.002,"endTime":3279.485,"body":"know is size and mass, they appear very similar."},{"startTime":3279.625,"endTime":3283.525,"body":"So a big reason for, for doing more, and there are three probes planned to"},{"startTime":3283.525,"endTime":3283.785,"body":"go to Venus in the next decade, is to try and see if we could"},{"startTime":3283.785,"endTime":3289.245,"body":"predict why that's so different from Earth."},{"startTime":3289.705,"endTime":3294.142,"body":"Um, and the magnetic field is clearly important for the atmosphere and, and presumably for"},{"startTime":3294.142,"endTime":3296.805,"body":"the survival of life on the surface as well."},{"startTime":3298.065,"endTime":3300.365,"body":"So we have another question from, uh, Slido."},{"startTime":3300.365,"endTime":3301.365,"body":"This one's from Vicki."},{"startTime":3301.665,"endTime":3306.205,"body":"Uh, do any other planets any other than Earth, I presume experience eclipses?"},{"startTime":3306.625,"endTime":3307.805,"body":"Oh, that's a really good question."},{"startTime":3307.835,"endTime":3308.125,"body":"Yeah."},{"startTime":3308.225,"endTime":3312.445,"body":"We have this marvelous thing that we get, um, total eclipses of the sun."},{"startTime":3313.105,"endTime":3316.427,"body":"Um, there's a great one in the States in April next year, if any of"},{"startTime":3316.427,"endTime":3319.085,"body":"you're looking for somewhere to go go to near the Mexican border."},{"startTime":3319.545,"endTime":3324.613,"body":"Um, so that happens because from earth, the moon and sun are about the same"},{"startTime":3324.613,"endTime":3325.965,"body":"size in the sky."},{"startTime":3326.705,"endTime":3329.765,"body":"In other planets, you do see moons go in front of the sun."},{"startTime":3329.765,"endTime":3331.565,"body":"So we've observed this from Mars."},{"startTime":3331.565,"endTime":3334.045,"body":"The rovers have looked up and seen FBOs and demo moss."},{"startTime":3334.065,"endTime":3336.085,"body":"The moon and Mars go across the sun."},{"startTime":3336.385,"endTime":3338.085,"body":"Uh, but they're much smaller than the sun."},{"startTime":3338.105,"endTime":3339.165,"body":"So it's more like a transit."},{"startTime":3339.165,"endTime":3341.085,"body":"Nowhere else has this coincidence."},{"startTime":3341.705,"endTime":3346.586,"body":"Um, now I think it's coincidence, my colleague Steve Babu thinks that that's the reason"},{"startTime":3346.586,"endTime":3346.911,"body":"we are here on earth because the same effect that makes them about the same"},{"startTime":3346.911,"endTime":3347.237,"body":"size in the sky means that the sun is also important in setting the tidal"},{"startTime":3347.237,"endTime":3357.325,"body":"strength on earth."},{"startTime":3357.345,"endTime":3362.318,"body":"So the moon controls the tides, the sun does the difference between spring and ne"},{"startTime":3362.318,"endTime":3363.645,"body":"tides for particularly dramatic."},{"startTime":3364.025,"endTime":3368.131,"body":"And that creates a range of environments that are sometimes but not always covered in"},{"startTime":3368.131,"endTime":3368.405,"body":"water."},{"startTime":3369.105,"endTime":3370.085,"body":"So, and they could be left."},{"startTime":3370.225,"endTime":3375.445,"body":"So Steve's argument is that land dwelling life took advantage of that opportunity and therefore"},{"startTime":3375.445,"endTime":3375.793,"body":"we should go looking for planets elsewhere in the galaxy that have moons the size"},{"startTime":3375.793,"endTime":3382.405,"body":"so that that will happen."},{"startTime":3382.425,"endTime":3384.805,"body":"And they're the the places where we'll find our Star Trek aliens."},{"startTime":3385.105,"endTime":3387.91,"body":"Um, the problem is we haven't found a single exo moon around another planet yet,"},{"startTime":3387.91,"endTime":3388.845,"body":"but we're working on it."},{"startTime":3389.865,"endTime":3392.805,"body":"I'm also being reminded that, that there were the Mr Ons on Mars."},{"startTime":3392.825,"endTime":3393.285,"body":"That's right."},{"startTime":3393.395,"endTime":3394.005,"body":"Yeah, yeah, of course."},{"startTime":3394.385,"endTime":3395.565,"body":"But I'm not allowed to talk about them."},{"startTime":3396.475,"endTime":3399.325,"body":"Similarly, the Clangers on the moon are, you can't talk about,"},{"startTime":3399.665,"endTime":3401.525,"body":"And as for the man and the moon will."},{"startTime":3401.595,"endTime":3401.885,"body":"Yeah."},{"startTime":3402.035,"endTime":3402.325,"body":"Yeah."},{"startTime":3402.325,"endTime":3402.845,"body":"We won't go there."},{"startTime":3402.895,"endTime":3403.685,"body":"Loved your lecture."},{"startTime":3403.685,"endTime":3404.365,"body":"Thank you very much."},{"startTime":3404.825,"endTime":3409.735,"body":"Um, and you touched on this when you talked about, um, maybe Russia now not"},{"startTime":3409.735,"endTime":3411.045,"body":"contributing to a probe."},{"startTime":3411.065,"endTime":3411.845,"body":"Was it going somewhere?"},{"startTime":3411.925,"endTime":3416.125,"body":"I can't remember where, but also ethically, who do you think the universe and the"},{"startTime":3416.125,"endTime":3417.245,"body":"solar system belongs to?"},{"startTime":3417.505,"endTime":3420.045,"body":"And when you talk about, you know, the race, whether it's Yeah."},{"startTime":3420.485,"endTime":3422.765,"body":"Scientists or, or billionaires or a combination of both."},{"startTime":3422.915,"endTime":3424.365,"body":"What you know, who, yeah."},{"startTime":3424.595,"endTime":3426.085,"body":"What are the rules and should there be rules?"},{"startTime":3426.395,"endTime":3427.325,"body":"Well, there should be rules."},{"startTime":3427.565,"endTime":3427.805,"body":"I think."},{"startTime":3427.965,"endTime":3429.685,"body":"I don't, I mean, obviously I should be in charge."},{"startTime":3430.185,"endTime":3431.925,"body":"Um, and then we'll do some science."},{"startTime":3432.385,"endTime":3436.542,"body":"Um, there, there is a rule that says that nothing in space can belie belong"},{"startTime":3436.542,"endTime":3436.819,"body":"to any country that's, there's a un treaty that says that whether that will hold"},{"startTime":3436.819,"endTime":3442.085,"body":"up when people start traveling."},{"startTime":3442.205,"endTime":3443.005,"body":"I, I don't know."},{"startTime":3443.705,"endTime":3449.324,"body":"Um, I think there's an environmentalism needed like Mar especially if you take Steve's point,"},{"startTime":3449.324,"endTime":3453.445,"body":"Steve Squire's point, that Mars is beautiful because it's not earth."},{"startTime":3454.645,"endTime":3458.8,"body":"I think we're at risk of turning it into earth if the only people who"},{"startTime":3458.8,"endTime":3459.077,"body":"go are billionaires, uh, who can afford to go, or Elon Musk talks about colonialism"},{"startTime":3459.077,"endTime":3459.354,"body":"and talks about people paying their way and going and living there and serving out"},{"startTime":3459.354,"endTime":3469.605,"body":"time so they can pay for their, their flight."},{"startTime":3470.345,"endTime":3473.085,"body":"So I think we, we do need to think about this stuff carefully."},{"startTime":3473.585,"endTime":3477.219,"body":"Um, for Mars in particular, I think the thing we should do first is go"},{"startTime":3477.219,"endTime":3479.885,"body":"to FBOs, which is its nearest moon, get a brilliant view."},{"startTime":3480.585,"endTime":3484.045,"body":"Um, you orbit Mars every, every few days you see the whole thing."},{"startTime":3484.045,"endTime":3485.805,"body":"You don't just have to go to one place on Mars."},{"startTime":3485.945,"endTime":3487.725,"body":"And from there we could really study the surface."},{"startTime":3487.985,"endTime":3490.605,"body":"So if I was setting the rules, I'd do that first."},{"startTime":3491.305,"endTime":3494.605,"body":"And then when we are sure we understand whether there's life there, then maybe we"},{"startTime":3494.605,"endTime":3495.925,"body":"can go and go and land."},{"startTime":3496.025,"endTime":3499.757,"body":"But if we ever go, I'm pretty sure it'll be people with flags, um, who"},{"startTime":3499.757,"endTime":3500.006,"body":"want to get there first and then it will more or less be a free"},{"startTime":3500.006,"endTime":3504.485,"body":"for all I think."},{"startTime":3505.895,"endTime":3506.325,"body":"Thank you."},{"startTime":3506.325,"endTime":3511.325,"body":"And that's a sort of, uh, a timely, slightly frightening reminder of how close, uh,"},{"startTime":3511.325,"endTime":3516.325,"body":"beauty and the quest for understanding can occasionally be to, um, the will to possess."},{"startTime":3516.475,"endTime":3519.765,"body":"However, on that note, Chris, thank you so much."},{"startTime":3519.795,"endTime":3520.525,"body":"That was brilliant."},{"startTime":3520.545,"endTime":3521.485,"body":"Can you join me in Thank."}]}