3I ATLAS Just Changed Course — And It’s Heading Toward Earth

[00:00:00]So, right now there's a highstakes chase happening in deep space. A Japanese ship is flying at full speed to hunt down something that technically shouldn't even exist. A dark comet.

[00:00:13]Now, these rocks are strange. They aren't asteroids, but they aren't comets either. They're this strange mix of both. Dark comets might hold the secret to how water first got to Earth, but they could also be a massive threat to our planet.

[00:00:29]Now we are getting closer to finding out how dangerous they really are. 5 years from now, a spacecraft named Heabusa 2 is set to reach a dark comet. The plan is to get really close, maybe even land, and just start collecting a ton of data.

[00:00:45]The funny thing is this whole [music] chase happened by total coincidence. So Heabusa 2 is basically Japan's cosmic treasure hunter. Launched back in [music] 2014, the spaceship flew millions of miles to reach a dark ancient asteroid called Rayugu. It finally got there in 2018, and that's when Heabusa [music] 2 deployed two rovers and a small lander onto the surface. Then a half a year later, it blasted the asteroid surface with something called a kinetic penetrator to collect samples. The spacecraft came back in 2020. [music] It swooped by Earth to drop off a capsule holding the asteroid sample.

[00:01:22]Thankfully, it all worked out and that capsule gave scientists important clues about the origin of water on Earth. But Heabusa 2 still had some fuel left. So, Japan decided to extend its mission and send it back to deep space. [music] This time to follow an asteroid called 1998 KY26.

[00:01:43]And by a huge coincidence, scientists later found out this space rock was actually a dark [music] comet. Yep. Just like the famous Amua Mua, that strange object that made headlines because it looks like an extraterrestrial [music] spaceship, this was the first known object that came from outside our solar system. And it was weird. Its speed and path around the sun didn't match a typical asteroid, but it also didn't have the bright tail or nucleus we normally associate with comets. So scientists started looking for more space rocks that acted the same way. and they actually found 14 of them. They basically fall into two groups. The outer dark comets and the, wait for it, [music] inner dark comets. The outer ones are these massive objects with really stretched out orbits. And they probably come from the outer solar system. By that, I mean way out past the asteroid belt. That's the neighborhood where you find the four giant planets, Jupiter, Saturn, Uranus, and Neptune, along with a ton of smaller icy rocks, moons, [music] and the Kyper belt. Then we've got the inner dark comets. [music] These are much smaller. They have orbits that are almost perfect circles, and they hang out in the inner solar system. That means they're a lot closer to Earth. But the one thing these rocks have in common is that they move like comets, but they don't [music] look like them. Normally, when a regular comet gets close to the sun, it heats up and releases gas and dust. That's what [music] gives it that bright cloud and long tail we normally see.

[00:03:20]But dark comets don't have a visible tail. If we look at them through a telescope, they look exactly like regular asteroids, but they [music] don't move in normal predictable orbits. As dark comets travel through space, they [music] slightly speed up or shift in ways that gravity alone just can't explain.

[00:03:39][music] So, something else has to be pushing them. Scientists think they might contain [music] ice. And if that's true, it's a massive deal. Because if ice is common on these little rocks flying near Earth, they might actually be the reason our planet has water today. That's one of the biggest mysteries we're still trying to solve.

[00:04:00]And that Japanese mission I mentioned earlier might actually provide some answers. Right now, Heabusa [music] 2 is out in deep space and it's on track to catch up with that dark comet by July 2031. [music] Now, since the spacecraft already pulled off that first landing on Rayuku, [music] you'd think we'd be like, "Okay, this next one will be a piece of cake."

[00:04:23]But that's not the case at all. I mean, just look at the difference between them. [music] This is Rayuku and this is KY26.

[00:04:32]Landing on something that tiny is much, much harder. Now, the team is a little worried [music] because when they first planned this mission, they had no idea this dark comet would be [music] so small. And here's the problem. The smaller these things are in space, the [music] faster they spin. According to the first measurements, KY26 was supposed to be a lot bigger, about 98 ft across and spinning [music] once every 10 minutes. But new telescope observations show it's actually only 36 ft across. And it's spinning so fast that it does a full rotation every 5 minutes. That makes the mission way more interesting, but also a lot more challenging. [music] The truth is, the team really doesn't know what to expect or what it's going to look like. Now, Japan isn't alone in this race, though. The European Space Agency [music] is also planning to launch their own mission to look for similar comets. Sometime in late 2028 or early 2029, they plan to launch the Comet Interceptor. The idea is to visit a [music] comet coming straight from the outer edges of our solar system. See, if they can catch a comet that has never passed [music] near the sun before, it'll give us a perfect look at the raw materials from the very beginning of our solar system. Basically, they want to catch more interstellar visits. Just like Amua Mua, these objects are really tough to study since we only spot them when they are already close to the sun.

[00:06:00]By the time we see them, there's just no time to plan and launch a whole mission.

[00:06:05]So, this time they're doing it a little differently.

[00:06:08]>> [music] >> The comet interceptor is going to be parked out in space ahead of time in a spot known as the second Lrange point.

[00:06:15][music] This is an area located about a million miles directly behind Earth. If you're looking from the sun out there, gravitational [music] forces from the sun and Earth and the orbital motion of a body balance each other [music] out.

[00:06:28]It lets a spacecraft basically hover in a stable position right alongside [music] Earth as we orbit the sun. The comet interceptor will just stay parked right there waiting. Then the day telescopes down here spot the perfect comet passing by. Scientists will map out the intercept location. The main spacecraft will fly out and release two smaller probes so they can observe the comet from multiple angles at the same time.

[00:06:57]As we're finally getting closer to dark comets, two big fears come to mind.

[00:07:01]First, what if they aren't comets at all? I mean, what if they are artificial like some kind of extraterrestrial tech?

[00:07:10]This idea was brought up by Harvard astrophysicist Avi Lobe. He says some of the newly found near-Earth dark comets are [music] the perfect size to act like a mother ship. Because their gravity is so weak, dropping off smaller probes would be incredibly easy. If those probes were released at just the right time, they could be sent straight toward Earth. And if they had their own propulsion, they could slip right through our atmosphere without even making a big fireball. So, who knows?

[00:07:40]Maybe these rocks are actually high-tech gadgets from another interplanetary civilization.

[00:07:46]Then there's the second concern.

[00:07:48]Research suggests that up to 60% of near-Earth objects could actually be dark comets, which means they aren't rare at all. And if they are that common, they could be a massive untrackable danger to Earth. They're small, fast, and really hard to spot.

[00:08:05]But most importantly, they don't behave like their regular asteroid and cometic cousins, which makes them completely unpredictable.

[00:08:13]Well, at the end of the day, if we want to keep Earth safe from these invisible threats, we definitely need to figure out exactly what these dark comets are and where they're heading. But it's not just about planetary defense. Cracking this mystery could completely rewrite the playbook for how we explore deep space. [music] And it might even kick off a whole new era of asteroid mining. The universe is hiding these things right in our own backyard. Now it's a race to catch one before it catches us.

[00:08:46]Well, the space object threeey atlas just whipped past the sun. And instead of clearing things up, the new images made everything even stranger. Because if this thing really is a comet, then it's the strangest comet ever recorded.

[00:09:02]And if it's not a comet, then we're watching something completely new invade our solar system. So, should we be worried? This all started back in July 2025.

[00:09:14]Astronomers using the Atlas Survey Telescope in Chile spotted a faint super fastmoving object, something unlike anything they had seen before. That was our first look at Threeey Atlas. And right away, scientists had a lot of questions. Where did it come from?

[00:09:33]What's it made of? But more importantly, what is this thing? At first glance, it almost looks like a tiny cell, right?

[00:09:41]like something you'd see under a microscope with a bright center like a nucleus and this fuzzy outer layer. But when we look at it from a different angle, the mystery clears up that glow is actually a comet tail. It's precisely because it looks like and behaves like a comet that NASA finally confirmed it.

[00:10:02]Yep, three eye atlas really is a comet.

[00:10:05]The big giveaway is that it has an icy nucleus [music] and a coma, which is that glowing cloud of gas and dust surrounding it. But this comet is a very special [music] one because it didn't come from our own solar system. It came from somewhere else in the Milky Way.

[00:10:22]And that's ridiculously rare. To give you an idea, we've only ever seen three objects like this, period. The first two interstellar visits were the famous Amua Mua and the comet Boris and now three eye atlas. Cool. But you might be asking, how do we know it actually came from outside our solar system? You see, normal comets are bound to the sun. They swing around it in these big looping orbits. But three Atlas isn't doing that. Its crazy speed and path show it's not on a closed orbit around the sun.

[00:11:01]And the only logical explanation is that it came from another star system and you know just wandered into ours by chance.

[00:11:09]In other words, this is just a visitor passing through our solar system and is doing it at a ridiculous speed. When we first spotted it, it was going around 137,000 mph. So, this object probably spent millions of years cruising through deep space [music] just to hang around our solar system for a few months. And after this quick visit, it'll vanish into interstellar space, and we'll never see it again. Recently, two European Space Agency satellites along with several NASA spacecraft near Mars captured new images of three Atlas zooming in as it passed the red planet.

[00:11:49]And one of those images is pretty incredible, showing a cloud of hydrogen atoms around the comet. Scientists were pretty excited about that as every bit of information we get from this visitor matters. Because the reality is there are still a lot of unanswered questions about this object, starting with its size. We can't pin it down exactly yet, but NASA says it could be anywhere from about 1,400 ft to around 3.5 m in diameter. Its exact shape is another mystery because our telescopes can't really get a clear look at it. The nucleus is buried inside this [music] bright coma of gas and dust, and the sunlight reflecting off all that dust basically blinds us. So, for now, we're trying to see it through a bright dusty fog. If you put all the pieces together, its behavior, its chemistry, and the images we've gotten so far, everything points to three Atlas being a comet. But even with all that, there are still some pretty controversial ideas floating around about what it might be. Not long after it was discovered, Harvard astrophysicist Avi Lobe said there is maybe a 30 to 40% chance this object isn't something naturally formed. That comment kicked off a wave of online buzz with people jumping to wild possibilities. Like maybe it's some kind of extraterrestrial tech or worse a threat to Earth. Ooh. According to this theory, ThreeI Atlas might be a massive extraterrestrial mother ship. Its odd trajectory could mean it's sending out little satellites toward Jupiter to collect intel for some extraterrestrial civilization. So, in that version of the story, this isn't just a comet. It's basically advanced space spy tech. But then the obvious question is why spy on Jupiter, right? I mean, wouldn't Earth be way more interesting to an interstellar civilization? Well, in this theory, Jupiter is the target because it's so much bigger than Earth and the other neighboring planets. The idea that a planet that massive could act kind of as a interstellar beacon, something that stands out from far away. The region near Jupiter is another big reason. It's almost like it's an ideal parking spot where space technology could basically hang out without using much fuel at all.

[00:14:20]In other words, if you were going to place advanced satellites somewhere to watch a planet, well, that's prime real estate. Pretty cool, huh? But as fun as that theory is, we got to come back down to Earth for a second. According to the major space agencies, this thing is a comet. Case closed. But that label doesn't make it any less special. Three Atlas is still a total weirdo in the best way. And it stands out for a bunch of reasons. Let's look at three of [music] the most important ones. First, this object is old. Like really old.

[00:14:57]Older than me. Scientists think it's been traveling through space for at least 7 billion years. That's so far back in time that it was formed before our sun and Earth even existed. [music] So yeah, it's probably the most ancient thing we've ever seen in our cosmic neighborhood. Second, it's glow. Comets can sometimes [music] look kind of green, and here's why. When a comet gets closer to the sun, the ice inside it heats up and starts releasing gas. I know the feeling. Some of that gas is made of carbon-based molecules, especially one called diatomic carbon or C2.

[00:15:36]>> [music] >> When sunlight hits those molecules, they light up and to us that glow shows up as green. But with three eye atlas, that green color is well confusing. The data suggests that this comet is actually low on those carbon chain molecules. So the big mystery is [music] if it doesn't have much C2, how is it glowing green at all? Well, nobody knows.

[00:16:02]>> [music] >> And now the third thing that makes this comet stand out. It seems to be giving off a metal alloy we've basically never seen in nature. [music] So this comet is releasing a plume that contains nickel.

[00:16:14]That's normal. What's strange [music] is what's missing, iron. In comets, nickel and iron usually show up in pretty similar amounts. Here we're seeing nickel, but no clear sign of iron. And that's almost unheard of. If the data holds up, it points to an alloy called nickel tetracarbonol, something we've only ever seen before in humanmade industrial processes, not out in space. No other known object has shown this kind of signature. Well, now that you're familiar with three Atlas, we got to answer the biggest question of all. Is it a threat to us? Good news, no. The comet isn't dangerous, [music] and it's going to stay really far from Earth. so we can all take a deep breath.

[00:17:02][sighs and gasps] Well, I feel better. Although it's harmless, tracking it has been super valuable for planetary defense. You see, space agencies are always watching asteroids and comets, [music] running the numbers on their orbits, and making sure we'd get a warning if something ever did head our way. But three Atlas gave them something new to practice with. This is the first time tracking data from [music] spacecraft orbiting another planet were officially submitted to and accepted by the minor planet center. That's the big global database [music] where asteroid and comet observations get collected and checked so scientists [music] everywhere can stay on the same page. So in a way three Atlas was like a rehearsal. Gathering data like this [music] from a totally new setup helps researchers sharpen their methods and improve how we spot future space objects. [music] And that means better detection, faster tracking, and more readiness, just in case the next visitor isn't [music] quite so friendly. Uh-oh.

[00:18:08]A mysterious space visitor has recently passed its closest approach to Earth, flying by at a distance of 64 million miles. It might be something totally natural and born on the outskirts of the solar system. Or some unknown civilization could be examining us from above right at this moment. This new object looks a lot like another strange wanderer called Threeey Atlas. And you'll understand why we say strange [music] pretty soon. So, could both of them come from the same place [music] outside our solar system? What we do know is that this new object is relatively close to us in [music] space terms of course and scientists are now studying it closely. They first spotted it inside our solar system and people are paying attention because it showed up not long after threeey atlas passed near our sun. On November 2nd, 2025, astronomer Gennady Borosov, the same person who discovered interstellar comet 2i Boros in 2019, found this new object.

[00:19:17]It's now got its official name and is listed in NASA's and the Minor Planet Centers databases.

[00:19:24]C 2025V1 has some unusual features. Its orbit is tilted 113°, which means it's moving almost up and over the regular path that planets take.

[00:19:37]Even more bizarre, its orbital plane is almost at a right angle to the path of three eye atlas. Plus, it doesn't have a clear comet tail, which is odd. Right now, its orbit has an eccentricity of 1.0095.

[00:19:54]And let me break it down in human language. If that number was well above one, it would mean the object definitely came from outside the solar system. But because it's only just a bit above one, the most likely explanation is that C 2025V1 came from the or cloud. That's a giant faraway shell of icy objects that surrounds the solar system. Now, scientists check this by basically rewinding the object's path, sending it all the way back to about 1,000 AU.

[00:20:28]That's 1,000 times farther than the Earth is from the Sun. At that huge distance, the planets can't mess with its motion anymore. [music] When they redo the orbit from that point, its eccentricity, the number that tells you if it's from outside the solar system, usually drops below one, which [music] means it's still part of our solar system. But at the same time, even a tiny push from Jupiter while passing by could make even a normal Orort cloud comet look like it has an eccentricity slightly above one. And on top of that, small blasts of gas coming off the comet surface can also change the numbers [music] a little. So to put it simply, it probably isn't interstellar. It just looks that way because of small pushes and gas bursts.

[00:21:19]C2025V1 is still exciting even if it comes from the or cloud because studying it gives us a chance to analyze the material from that distant [music] region and learn how our solar system formed and evolved.

[00:21:33]Now let's get back to the mystery of threeey atlas. Before anything else, let's [music] explain what threeey actually is. It's most likely a comet.

[00:21:43]Basically a huge dirty snowball flying through space. You can't see it with your own eyes or with a regular telescope. But there's good news. A powerful telescope in Italy is streaming it live for free. So, anyone can actually watch this mysterious object as it passes by. [music] Scientists think this comet weighs about 33 billion tons.

[00:22:07]That number is hard to imagine, so here are a few comparisons. The Eiffel Tower weighs around 10,000 tons. So 33 billion tons is the same as a whopping 3.3 million Eiffel Towers. And if you decide to compare the Space Visitor to buildings, 33 billion tons is about the same as the weight of several huge city areas made entirely of steel and concrete. But even all that size isn't the wildest part. Some experts think this object might be a piece of unknown technology from outside our galaxy. And they're not saying this just for fun.

[00:22:44]There are real reasons behind the theory. Three Atlas was first noticed in July by NASA's [music] Asteroid Terrestrial Impact Last Alert System or [music] Atlas. Shortly after, NASA confirmed that the object wasn't from our solar system at all. It's an interstellar object, only the third ever discovered. The first one was Amoaam Mua in 2017 which looked long and flat and didn't behave like a normal rock. The second was comet BI Boros in [music] 2019.

[00:23:20]Now we have three Atlas and it is enormous compared with the other two.

[00:23:25]Its nucleus is up to 3 and 1/2 m wide while Amua Mua was only about a/4 mile long and Boris was around a half mile across. Besides being huge, 3i Atlas is unusual in several other ways. As it moves through the solar system, it's releasing massive amounts of carbon dioxide and gas. This suggests that three Atlas is 3 to five orders of magnitude, which means 1,000 to 100,000 times more massive than the other two known interstellar visitors. Such an enormous difference is a real scientific mystery. It's also traveling incredibly fast, about 150,000 mph, which is almost 200 times the speed of sound. And unlike objects in our solar system, which followed curved paths because of gravity, 3i Atlas is moving on a nearly straight line. That alone makes it stand out. These odd behaviors have led some researchers to consider a pretty unexpected idea. Three Atlas might be a probe sent by another civilization, possibly to study Earth. According to this theory, the object could be a sign of some kind of intelligence from beyond our solar system. Why do they think this? [music] Well, because the object's movement doesn't match what you'd expect from something controlled only by gravity. It also passes close to Venus, Mars, [music] and Jupiter. And these are the planets that might be especially interesting for an outside civilization to observe.

[00:25:05]Another very unusual feature of threeey atlas's path is that its orbit is tilted only a little compared to the plane of the solar system about 5° and it moves in the opposite direction [music] to most planets. This feature might allow the object or its creators to take extremely precise measurements of planets. things like their orbits and sizes [music] to plan a perfect flight route through the solar system. And if threeey Atlas suddenly changes [music] direction at some point, that could mean it's using a built-in engine instead of simply drifting through space. Now, new photos have also shown that three Atlas has at least seven jets blasting material into space, some shooting in totally opposite directions. Now, if this thing is just a normal comet, it would have had to lose a huge amount of its original [music] mass when it passed near the sun, way more than just 10 to 20%. Only some of that material would actually push the object in [music] one direction. So, the total amount blown off would need to be massive. If that's what happened, then there should be now a giant cloud of gas and dust around three eye atlas. And if that cloud exists, it'll be pretty easy to figure out what the comet is made of.

[00:26:26]The James Web Space Telescope [music] will check this when ThreeI Atlas gets closest to Earth on December 19th, 2025.

[00:26:35]But if ThreeI Atlas is not a normal comet and is actually some kind of technology, it wouldn't need to lose that much material. Engines built by an advanced civilization could give it a boost while using way less gas because they shoot it out way faster. Faster exhaust gives more push with less fuel.

[00:26:56]So a technological object wouldn't need to blast away big chunks of itself the way a natural comet would. So to sum it up, there's still a big mystery around three Atlas. Could it really be a technological mother ship that released small probes into the inner solar system? But C25V1 doesn't fit that idea, unless one of the objects use some kind of engine. The closest their orbits ever come is about 46 million miles and the two objects [music] themselves were never closer to each other than about 140 million miles.

[00:27:34]The tiny non-gravitational push detected in 3i Atlas is nowhere near strong enough to close this gap. [music] So C 20251 is almost certainly not one of the many probes people imagine 3i Atlas might have released. A large space probe is nearing the sun. The terrifying heat of the star begins to melt the shell of the spacecraft. Another moment and the probe bursts into flames. In no time, it disintegrates in a powerful explosion.

[00:28:06]Ah, what a sad ending. If it were true, it was not a probe. It was a comet known as Threeey Atlas. And despite everything people say, it's still intact and thriving. The thing is, there is a rumor online saying that comet Threeey Atlas exploded when it got closest to the sun.

[00:28:26]But astronomers say this is not true.

[00:28:29]There was no explosion. And the comet's nucleus still looks whole and undamaged, which is kind of surprising since comets that pass very close to the sun usually go through some serious changes. You see, comets are made of a mix of ice, dust, and rocky material, which is why they're often called dirty snowballs. So when they come close to the sun, the intense heat from our star makes their ice turn into gas. This new gas can burst out in huge jets, form a cloud around the comet called a coma, and or be pushed away into a long tail.

[00:29:05]Sunlight makes all of these parts shine more brightly, and even people with small or simple telescopes can study the comet if the viewing conditions are good. But aside from being a breathtaking view, such a close approach can break off pieces of a comet or even tear its whole nucleus apart.

[00:29:24]Now, it's true that some comets survive this process, but many, especially small ones or comets entering the inner solar system for the first time, break into pieces or disappear completely. Well, three Atlas acted differently. So there it reached its closest point to the sun on October 29th, 2025. This point is called the perhion. At that moment, the comet was about 130 million miles from the sun. That's about 1 and 1/2 times the distance between the sun and our planet. The comet was also on the opposite side of the sun from Earth. So the star was blocking it from our view and we couldn't see the comet. Anyway, even though threeey atlas could hypothetically break apart or release lots of fragments, it didn't. The nucleus stayed intact, and this made the comet's behavior even more unusual and interesting to scientists. They looked closely at the new photos and said everything looked normal.

[00:30:24]Now, interestingly, the day before, some people thought the comet had broken into pieces after it came out from behind the far side of the sun. This idea became popular after a blog post said the comet had lost a lot of mass. So to make this claim, the blog used photos taken on November 9th by two small telescopes in Spain. The pictures show jets of gas coming out of the comet. The scientists used this to estimate how much material was coming off the comet, claiming that it should have broken into at least 16 pieces. However, many scientists have questioned this statement. Most researchers say there's no proof that the comet exploded. One scientist who studies the comet says that all the images he had seen showed a completely normal, healthy comet. There's no sign that the main body of the comet has broken apart. Still, now that the comet is coming back into view, astronomers are watching it very carefully. They want to learn more about the comet's materials and structure. Right now, if you look at it from Earth, the comet seems to be slowly moving higher in the eastern sky. If the weather is good, people in many parts of the northern hemisphere can see it with a small telescope like this one with a 6-in lens. And many do pay attention to the comet. Since it was discovered in July, it has become the center of many curious ideas. Some people are sure that the comet, which comes from outside our solar system and might be more than 7 billion years old, could be a probe sent by a different civilization. Now, most astronomers strongly disagree, of course. They believe the comet is completely natural and comes from another star system somewhere in the Milky Way. And this is actually exciting. Comet 3i Atlas is only the third interstellar comet ever seen [music] and it is the largest one of its kind. Before it was comet 2i Borosoft that passed through in 2019 [music] and Amua Mua, a weird and long aaded object that appeared in 2017. But threeey atlas with its up [music] to three and a half mile nucleus dwarfs a Mua Mua which was just a/4 mile long and Borosoft which is about 3/10 of a mile across. Plus 3i Atlas may be the oldest comet humans have ever observed. Omo Mua is much younger around 1 billion years old. It came from the galaxy's thin disc where new stars are still being born. It was the first known object from another star system to pass through our solar system.

[00:33:01]Basically our first interstellar gas. It was super stretched out about 10 times longer than it was wide unlike anything else we've spotted in space. As for two I Boris, it sits in between at roughly 1.7 billion years old. It also came from the thin disc. [music] It was the first confirmed comet to come from another star system, and it gave scientists a super rare peak at what materials beyond our solar system were made of. Unlike the first interstellar visitor, Umoa Mua, which looked more like an asteroid, Borosoft behaved like a classic comet, it had a bright coma, [music] a temporary fuzzy atmosphere of gas and dust forming around the comet's nucleus as it approaches the sun. Plus, it also had a long tail of dust and gas.

[00:33:50]Now, two I Boris is speeding away from the sun and will never return. But it allowed scientists to take a glimpse into the chemistry and history of distant worlds. Now, let's get back to comet 3adlas. It will pass closest to Earth on December 19th. Until then, scientists will make many more observations. People will also make many new claims about the comet, that's for sure. But it's best to be cautious and not believe everything immediately. By the way, even though you can't see this famous [music] comet with your own eyes or with a regular telescope, hey, that's good news. A powerful telescope in Italy is streaming it live for free. Wo! So, anyone can actually watch this mysterious object as it passes by.

[00:34:36]Scientists [music] think this comet weighs about 33 billion tons. That's a big number. How about we make a few comparisons? [music] The Eiffel Tower weighs around 10,000 tons. So 33 billion tons is the same as 3.3 [music] million Eiffel Towers. And if you decide to compare the space [music] visitor to buildings, well, 33 billion tons is about the same as the weight of several huge city areas made entirely of steel and concrete. Now, ThreeI Atlas was first noticed in July by NASA's Asteroid Terrestrial Impact Last Alert System, which if you're paying attention is where they got the nickname Atlas.

[00:35:16][music] Shortly after, NASA confirmed that the object wasn't from our solar system at all. Now, besides being huge, three Atlas is unusual in several other ways.

[00:35:27]As it moves through the solar system, it's releasing massive amounts of carbon dioxide and dust. So this suggests that three eye atlas is 3 to five orders of magnitude, which means 1,000 to 100,000 times [music] more massive than the two other known interstellar visitors. Such an enormous difference is a real scientific mystery. It's also traveling incredibly fast, about 150,000 mph, which is almost 200 times [music] the speed of sound. Hey, that will get you a speeding ticket. And unlike objects in our solar system which follow curved paths because of gravity, threeey atlas is moving on a nearly straight line.

[00:36:08]That alone makes it stand out. Now that the comet has moved past the sun, telescopes on Earth can see it again.

[00:36:15]Comet 3i Atlas is important to us because it's only the third interstellar visitor we've ever seen and it may be the biggest and oldest one yet. And it didn't break apart near the sun like some other comets. By studying it, scientists [music] can learn what materials exist in other star systems and better understand how comets and even planets form in our galaxy.