What was the Bloop?

Imagine screaming so loud that someone hears you on the exact opposite side of the country! In the summer of 1997, scientists using super-sensitive underwater microphones called hydrophones recorded an incredible sound deep in the ocean. It was so loud it traveled over 3,000 miles underwater. They called it the Bloop! But what made this mysterious noise? The sound was significantly louder than a blue whale—the loudest animal on Earth. Because the sound waves looked organic, people everywhere started to wonder: was there a giant, undiscovered sea monster lurking in the deepest, darkest depths near Antarctica? For years, the Bloop was one of the ocean's greatest unsolved mysteries! Join Mira and Finn as they dive into this thrilling deep-sea detective story! You will learn all about the secret underwater SOFAR channel, how the Navy spies on the ocean floor, and the epic final reveal of what the Bloop actually was (hint: it involves snapping glaciers and massive icequakes!). Get ready to hold your breath and plunge into the watery unknown!

Transcript

SPEAKER_00 0:48

Welcome to Science Is Not Boring by Kodopoly.com. I'm Mira! And I'm Finn! Before we dive into today's mystery, a huge hello to August, who is eight, and Mira, who is six.

SPEAKER_01 1:01

They loved our King Arthur episode and asked all about the bloop. What an awesome mystery. This one is for you both.

SPEAKER_00 1:09

Okay, Finn, imagine screaming so loud that someone hears you on the exact opposite side of the country.

SPEAKER_01 1:17

I think my parents would say I can already do that.

SPEAKER_00 1:20

Well, in the summer of 1997, scientists recorded a sound in the deep ocean that was so massive it travelled over 3,000 miles underwater.

SPEAKER_01 1:32

3,000 miles? That is like hearing a sound in New York all the way from California. Or hearing a shout in London from across the ocean.

SPEAKER_00 1:41

Exactly. And the wildest part? The scientists had no idea what made it. It sounded alive, but it was way too loud to be any known animal.

SPEAKER_01 1:51

Wait, so people thought there was a giant unknown sea monster lurking in the dark?

SPEAKER_00 1:56

They really did. Today we are diving into one of the ocean's greatest detective stories, the mystery of the bloop. Get ready to hold your breath as we go deep into the unknown. To understand this mystery, we have to talk about how we listen to the ocean. Have you ever dunked your head underwater in the bathtub and listened to how weird everything sounds?

SPEAKER_01 2:19

Yeah, the water makes everything sound kind of echoey and muffled.

SPEAKER_00 2:24

Right. Well, water is actually amazing at carrying sound. And an agency called NOAA, the National Oceanic and Atmospheric Administration, takes advantage of that. How do they listen to the whole ocean?

SPEAKER_01 2:39

Do they just stick a really long tube in the water?

SPEAKER_00 2:42

Not quite. They use something called hydrophones. These are super sensitive underwater microphones. Whoa! How many do they have? A lot. Back in the 1990s, NOAA supplemented a network called the Sound Surveillance System with their own autonomous arrays.

SPEAKER_01 3:03

That is a really long name. Who built it?

SPEAKER_00 3:06

Here is the cool part. The United States Navy originally built that surveillance system during the Cold War. They secretly placed microphones deep on the ocean floor to listen for enemy submarines.

SPEAKER_01 3:20

Oh, like a giant tripwire of underwater spies. That is so cool.

SPEAKER_00 3:25

Exactly! But when the Cold War ended, the military didn't need them as much. So, scientists at NOAA got permission to use this amazing network to listen to the ocean. What were they hoping to hear? Whale singing? Sunken pirate ships? Whales, underwater volcanoes, and earthquakes. Dr. Christopher Fox was the chief scientist listening to these feeds. And usually the sounds were totally normal.

SPEAKER_01 3:54

Until the summer of 1997.

SPEAKER_00 3:57

In the summer of 1997, Dr. Fox and his team picked up something completely unexpected. Was it the bloop? What did it sound like? It was a super low-frequency rumble that lasted for about exactly one minute. It started low and smoothly rose up in pitch.

SPEAKER_01 4:16

Like bloop?

SPEAKER_00 4:19

Sort of. The pitch was so low that humans could barely hear it. But when they sped the recording up 16 times, it sounded exactly like a giant bubble popping. Bloop. So it was just a bubble? No way! This sound was so overwhelmingly loud, it was picked up by multiple hydrophones that were over 3,000 miles apart. That is 5,000 kilometres.

SPEAKER_01 4:46

3,000 miles? Wait, how loud was it compared to, say, a blue whale?

SPEAKER_00 4:52

A blue whale is the loudest low-frequency animal on Earth, but the bloop was significantly louder than any whale noise ever recorded.

SPEAKER_01 5:01

Louder than a blue whale? What could be louder than the biggest animal on the planet?

SPEAKER_00 5:05

That is exactly what Dr. Fox wondered. When he looked at the sound waves on a visual graph called a spectrogram, he noticed something spooky. It looked organic. Organic?

SPEAKER_01 5:18

You mean it looked like an animal made it?

SPEAKER_00 5:20

Yes. The way the sound quickly changed pitch looked exactly like a living marine beast making a call.

SPEAKER_01 5:27

But if it was louder than a blue whale, that means it would have to be an animal two or three times bigger than a blue whale.

SPEAKER_00 5:33

Exactly! The news got out and people started going crazy. Was it a giant undiscovered squid? Was it a prehistoric sea monster hiding at the bottom of the ocean? To make things even creepier, the scientists tracked where the sound came from. It originated deep in the South Pacific Ocean, near Antarctica.

SPEAKER_01 5:54

That is super remote, right?

SPEAKER_00 5:57

Very. In fact, it was near a place called Point Nemo. That is the oceanic pole of inaccessibility, which is the absolute most remote spot on planet Earth.

SPEAKER_01 6:10

Okay, so a giant unknown sea monster living at the most remote place on Earth where no humans ever go. Did they send a submarine down to look for it?

SPEAKER_00 6:22

No, the ocean is way too deep and dark there. But they kept listening. For years, the bloop was one of the ocean's greatest unsolved mysteries.

SPEAKER_01 6:32

What was it? Please tell me it was a giant squid with tentacles the size of a skyscraper.

SPEAKER_00 6:39

Sorry, Finn. Years later, an oceanographer named Robert Ziyak led an acoustic survey near the coast of Antarctica. They placed new microphones in the Bransfield Strait and the Ross Sea. And what did they hear? They started hearing tens of thousands of sounds that were essentially identical to the bloop.

SPEAKER_01 7:01

Wait, tens of thousands of monsters? That is even scarier! Nope, not monsters. They were icequakes. Icequakes? Like an earthquake, but made of ice.

SPEAKER_00 7:14

Exactly! They discovered the bloop was actually the sound of an enormous iceberg violently cracking and breaking away from an Antarctic glacier. It is a process called ice carving.

SPEAKER_01 7:26

A block of ice made a sound louder than a blue whale.

SPEAKER_00 7:30

Yes! Imagine a piece of ice the size of an entire city snapping in half and crashing into the freezing ocean. The immense friction and fracturing of billions of tons of ice created a thunderous rumble.

SPEAKER_01 7:45

Whoa! So the bloop was just an iceberg snapping? That is actually just as epic as a sea monster.

SPEAKER_00 7:53

It really is! In 2008, they recorded a massive iceberg named A53A disintegrating, and the sound perfectly matched the bloop.

SPEAKER_01 8:04

But wait, how could a sound, even a loud one, travel 3,000 miles without fading away?

SPEAKER_00 8:11

That is thanks to something called the Sofar Channel. SoFar stands for sound fixing and ranging.

SPEAKER_01 8:17

So it is like a secret tunnel for sound.

SPEAKER_00 8:20

Basically, at a certain depth, the water pressure and temperature create a perfect acoustic channel. Sound gets trapped in this layer and can travel thousands of miles without losing much energy.

SPEAKER_01 8:33

That is wild. Does knowing about the bloop actually help scientists today?

SPEAKER_00 8:38

It really does. By listening to these massive icequakes, scientists can track how fast glaciers in Antarctica are melting. It helps them study the ice, even when it is completely dark and freezing, during the Antarctic winter.

SPEAKER_01 8:54

Okay, I love that. Do you have any other weird sound facts?

SPEAKER_00 8:58

I do! Did you know that size does not always equal volume? The pistol shrimp is only a few centimetres long, but it snaps its claw so fast, it creates a bubble that pops with the volume of a jet engine.

SPEAKER_01 9:13

No way! A tiny shrimp as loud as a jet. The ocean is so weird.

SPEAKER_00 9:19

It really is, and it proves there are still so many incredible mysteries waiting to be discovered in the deep dark ocean. Alright, Finn, it is time for the quiz! Are you ready to test your bloop knowledge?

SPEAKER_01 9:32

Okay, I'm ready. Hit me with the questions.

SPEAKER_00 9:36

First question. What year did scientists first record the mysterious bloop sound? Next one. What is the name of the underwater microphones used to listen to the ocean? Question three. How far apart were the sensors that picked up the bloop? Here's number four. What is the loudest low frequency animal on Earth but was still quieter than the bloop? Last question. What actually caused the bloop sound? Great job! Let's see how you did and go through the answers. The first answer is it was recorded in the summer of 1997. For question 2, the underwater microphones are called hydrophones. Number 3. The answer is the sensors were over 3,000 miles apart. Question 4. The blue whale is the loudest low frequency animal, but the bloop was much louder. And the final answer is the bloop was an icequake caused by a massive iceberg cracking.

SPEAKER_01 10:57

Man, I still can't believe a giant cracking iceberg tricked everyone into thinking there was a sea monster.

SPEAKER_00 11:04

I know, but that is the cool thing about science. It starts with a wild mystery and ends with an amazing discovery.

SPEAKER_01 11:12

If you loved this episode, please leave us a five-star review.

SPEAKER_00 11:16

Yes, just scroll down and tap the stars. And in your review, tell us what you would name your very own sea monster.

SPEAKER_01 11:23

Oh, and don't forget to check out our site kidopoly.com. We have got tons of fun learning games and activities there.

SPEAKER_00 11:30

And if you want to shout out on the show or just want to say hi, email us at hello at kidopoly.com. We would love to hear from you. Thanks for exploring the deep ocean with us today. See you next time on Science is Not Boring. Bye everyone.