00:00An asteroid broke off the moon, and now it's super close to Earth. Does it pose a danger to us?
00:05Kama'oale'a, also known as
00:082016 HO3, spins super quickly as it orbits near our planet. Let's call it HO3 for short.
00:17Astronomers found it on April 27, 2016.
00:21Compared to other asteroids, it's tiny. On Earth though,
00:25it would be the size of a small building, or about half the size of the London Eye Ferris wheel.
00:30They discovered it in Hawaii, and its name roughly translates to a fragment of something that seems to wobble.
00:37After some study, they realized that this asteroid might be a chunk of the moon that got blasted into space.
00:44There's a part of the moon called Giordano Bruno Crater,
00:48named after an Italian philosopher, that guy who had to pay quite the price for his ideas.
00:53If you look at it from space, Giordano Bruno stands out because it's surrounded by some rays of material.
01:00They're super huge, stretching over 93 miles, and are still bright. This means that an enormous boom once happened there.
01:08There's an interesting story about this. In 1178, five monks were traveling in Canterbury, England.
01:15Suddenly, they saw something strange happening on the moon.
01:18They said it looked like the moon was splitting with flames and sparks.
01:21Then, there was a darkening that spread all across the lunar surface.
01:26In the 20th century,
01:28scientists found these records, and thought that these monks saw the formation of the Giordano Bruno Crater.
01:33But later, it turned out that the crater is about 4 million years old.
01:38And thank the stars, because such a massive impact, if it really happened in the 12th century,
01:43would have gone crazy on our planet. It would have caused a huge meteor storm on Earth.
01:48In any case, our HO3 is most likely a piece of the moon that broke off during that impact 4 million years ago.
01:56Luckily, there's no need to panic about it. When astronomers spotted this sudden moon piece,
02:00they quickly tracked its orbit. Turns out, it won't collide with us any time soon.
02:05It's going to be our quasi-satellite for at least 300 more years.
02:10Meaning, it'll follow a path around the Sun that keeps it close to Earth without colliding.
02:15Its orbit is wild, though.
02:17It seems to be constantly looping around our planet in some pretty unique loops, moving closer and going away, up and down.
02:25And then, somewhere in the 24th century, it will go even more crazy, switching to a horseshoe orbit, slowly going away from us.
02:34Could HO3 collide with us someday?
02:37Maybe. But that would happen over millions of years, when it would leave its current orbit and collide with Earth,
02:44Venus, or even the Sun itself. Or maybe entirely ejected from the solar system.
02:49Even though it's one of the closest asteroids ever discovered, it's also one of the smallest and most stable ones.
02:56This discovery also opens up some exciting ideas about life in the universe. We see that rocks can travel between celestial bodies.
03:05There is a theory that life could have been spread all across the universe by traveling on these rocks, like on some space
03:12Ubers, or at least the building blocks of life, like carbon.
03:16Maybe life even hitchhiked to our planet on rocks from Mars.
03:20HO3 probably doesn't carry any life, but the fact that it can travel for millions of years, carrying stuff on it and feeling fine,
03:28supports this theory.
03:30Astronomers want to send something to investigate HO3.
03:34Back in 2017, a group of students gave an idea of using a spacecraft for it.
03:39The China National Space Administration wants to send a robotic probe to HO3, somewhere in 2025.
03:47The robot should fly there, collect samples, and bring them back to Earth for study.
03:53Unfortunately, you can't see this asteroid in the sky with the naked eye. Its size is about 130 to
04:01330 feet in diameter, so it would be too tiny and dim to see without a super powerful telescope.
04:08But, there is an asteroid that you'll be able to see, and it will be insane.
04:14In 2029, a large asteroid will pass so close to Earth that it will be visible to the naked eye.
04:20Make sure not to miss it, because this is a once-in-a-thousand-year event.
04:25The asteroid is known as
04:272004 MN4, or Apophis for short.
04:31It's much bigger than HO3, about a thousand two hundred ten feet wide.
04:36This will be the closest asteroid passage ever.
04:40This one actually caused some panic back in December 2004.
04:44All because there was a 2.7% chance that it could hit Earth in 2029.
04:50People were horrified. Even the name Apophis is inspired by an evil serpent from ancient Egyptian mythology.
04:58A huge monster that fought Ra and always tried to swallow the Sun and destroy the planet.
05:04Luckily, when scientists got more data,
05:07they realized that it would pass pretty close to us in 2029, and we'd be able to see it in the sky.
05:12But then, it will just fly away like a chill asteroid.
05:17There was another worry though.
05:19That during its close pass, Apophis might travel through something called a gravitational keyhole.
05:27Basically, that it could travel through a specific narrow region of space which would accidentally alter its orbit.
05:33And then it would make an epic comeback in 2036, like the planet from the movie Melancholia.
05:40However, after some calculations, scientists ruled out this possibility as well.
05:46Apophis will still come quite close to us in 2036,
05:49but it will be about as far away as Venus is when it overtakes Earth.
05:53And then, Apophis and Earth will just go their own separate ways.
05:58On average, an asteroid the size of Apophis is only expected to hit Earth once every 80,000 years.
06:05And if it did hit us, it would completely destroy a huge area, causing earthquakes and tsunamis all around the world.
06:12But it wouldn't cause an apocalypse or anything like that.
06:16You'd only be able to see Apophis from Europe, Africa, and Western Asia.
06:20So if you want to see it, you might need to travel.
06:24The asteroid will look like a fast-moving star in the night sky, shining bright enough to be seen without any special equipment.
06:31It would be easy to spot at night, though city lights might make it harder to see.
06:37Now, can you imagine that these are not the only guys hanging nearby?
06:42Both HO3 and Apophis are part of the so-called Apollo orbit asteroids.
06:47These are the asteroids with orbits going around Earth, an entire group of dangerous fellas.
06:54Since they cross Earth's orbit, they have the potential to come close to or even collide with our planet.
07:00The first asteroid of this group to be discovered was 1862 Apollo, named after the Greek deity of the Sun.
07:07It was first discovered in 1932, and the group was named after it.
07:13This one was even bigger, almost a mile in size. In fact, it's so huge that it even has its own tiny moon.
07:22Apollo crosses orbits of not just Earth, but also Venus and Mars.
07:28Fun fact, even though it was the first one of its kind, telescopes accidentally lost it out of view for over 40 years.
07:36So scientists went, oh, well, let's just keep the count of things we can see.
07:40When Apollo was rediscovered in 1973, it wasn't the first asteroid on the list and got a big number in its name.
07:49Apollo will fly near us during the next hundreds of years. In 2075, it will be somewhere around Venus,
07:56but it should fly by as well.
07:58In any case, there's no need to worry because astronomers are keeping a close track on these guys.
08:04If we were in any immediate danger, we'd have known.
08:08In order for an asteroid to totally destroy life on our planet,
08:11it should be bigger than six miles in diameter, like the one that helped to wipe out the dinosaurs 66 million years ago.
08:20But these guys are so crazy rare, we'd probably live on other planets by the time they arrive on Earth.
08:30That's it for today. So hey, if you pacified your curiosity,
08:33then give the video a like and share it with your friends. Or if you want more,
08:37just click on these videos and stay on the Bright Side!
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