00:00Let's see, there's Mercury, Venus, Earth, Mars, Phaeton, Jupiter, wait hold on, what
00:12Phaeton am I talking about?
00:14Well, let's see.
00:16It was the beginning of the 19th century, and the asteroid belt hadn't been discovered
00:21yet.
00:22In the year 1801, one man named Giuseppe Piazzi spotted the largest asteroid in the Solar
00:28System, Ceres.
00:30At that time, people believed that there was a planet orbiting between Mars and Jupiter,
00:36and Ceres seemed to fit the bill.
00:39But the next year, another astronomer, Heinrich Olbers, found one more space body following
00:44a similar orbit.
00:46It was an asteroid which was later called Pallas.
00:49This discovery helped Olbers to figure out that these two space objects could be fragments
00:54of a planet.
00:56The discovery of two more asteroids, Vesta and Juno, seemed to confirm this theory.
01:02It was believed that the planet, which was named Phaeton in the 20th century, appeared
01:07in the early days of the Solar System and was later destroyed, and its debris formed
01:12the asteroid belt.
01:13Olbers' idea was called the disruption theory.
01:17To astronomers at that time, it seemed obvious that the planet once collided with a large
01:21space object, which led to its demise.
01:26The most likely candidate was Nemesis, a hypothetical red or brown dwarf orbiting our
01:31Sun.
01:32Another theory claimed that Phaeton could have gone through an internal cataclysm, which
01:37could have broken the planet into pieces.
01:40There was one more idea – Phaeton could have come too close to Jupiter and got torn
01:44apart by the gas giant's immense gravity.
01:49These days, though, astronomers don't believe in the disruption theory anymore.
01:53A new idea has replaced it.
01:55It's known as the accretion theory.
01:58It claims that the asteroid belt is all that is left of the protoplanetary disk.
02:03Supposedly, this disk had been originally orbiting the Sun, even before the planets
02:08formed.
02:09Unfortunately, because of Jupiter's gravitational forces, it never managed to coalesce into
02:14a planet.
02:16But what is this asteroid belt we keep talking about?
02:19This region is located between the orbits of Jupiter and Mars.
02:23Tens of asteroids and even minor planets are found there.
02:27Some of them can sometimes migrate or even get thrown out of the asteroid belt to the
02:31outer Solar System.
02:34The four largest asteroids in that area are Ceres, Vesta, Pallas, and Hygieia.
02:41They make up half the mass of the entire belt.
02:44As for the rest of the mass, countless smaller bodies make up for it.
02:49In loads of sci-fi movies about space, the main character gets into an asteroid belt
02:54and has to try hard to get away from countless rocks threatening to smash their spacecraft.
03:00Well, it has nothing to do with the real thing.
03:04Even though there are thousands of asteroids in this region, they're so widely spaced
03:08that the chance of collision is next to nothing.
03:11Hey, but it's a movie, right?
03:14Anyway, when the asteroid belt was forming, some objects started to come together and
03:20form what we know as protoplanets.
03:24But the gravitational pull that was caused by the formation of Jupiter made such collisions
03:28too rough, and instead of forming large space bodies like planets, asteroids shuddered.
03:36Astronomers think that as a result of such collisions, more than 99.99% of the original
03:41mass of the asteroid belt was lost in the first 100 million years of the history of
03:47the Solar System.
03:50Only the largest asteroids have enough gravity to get a spherical shape.
03:55Small ones are just often piles of rubble loosely held together by gravity.
04:00And the tiniest objects in the asteroid belt resemble dust, so small they are.
04:05And all these objects, giant and tiny, orbit the Sun.
04:10There are several types of asteroids, depending on their composition and albedo, which is
04:14the proportion of light or radiation reflected by a surface.
04:18The main types are carbon asteroids, which have a very dark surface, silicon ones, you
04:24can also call them stone asteroids, and metal ones.
04:29The first two types account for around 75% and 17% of asteroids that we know about.
04:37For the first time, the asteroid belt was crossed by a spacecraft in 1972.
04:42It was the Pioneer 10 space probe.
04:44The spaceship managed to refute the theory that the belt was filled with dust that could
04:49easily damage all gadgets on board.
04:51It didn't happen.
04:53And since that time, 8 more probes have traveled through the asteroid belt.
04:58And now I'm gonna tell you some cool facts about the Solar System itself.
05:02Try to count how many of these facts you've known before and write your answer down in
05:06the comments below!
05:09The Solar System is a staggering 4.5 billion years old.
05:14Scientists came to this conclusion after studying meteorites, the oldest material they managed
05:18to find.
05:20But our Solar System isn't the only one in the Milky Way galaxy.
05:25The galaxy we live in houses about 100 billion star systems.
05:29And if it's just our galaxy alone, what can we say about the whole Universe?
05:36Our Sun is also insanely massive.
05:38Here's the proof – 99.86% of all the mass of the Solar System is the mass of the Sun.
05:45In particular, hydrogen and helium that it's made of.
05:49The remaining 0.14% is mostly the mass of the Solar System's 8 planets.
05:56By the way, contrary to popular misconception, outer space isn't a perfect vacuum.
06:02It contains not only stars and planets, but also clouds of interstellar dust, space plasma,
06:08and cosmic rays.
06:10Those are atom fragments dashing from the outskirts of the Solar System.
06:15One phenomenon astronauts should worry about while exploring space is cold welding.
06:21If two pieces of the same kind of metal touch in space, they bond and get permanently stuck
06:27together.
06:28Kinda like galaxy glue.
06:30It doesn't happen on Earth since water and air keep pieces separate.
06:36You can see solar eclipses even though the Moon is 400 times smaller than the Sun, it's
06:41also 400 times closer to Earth, so it's perfectly capable of obscuring the star.
06:47But in 600 million years, the Moon won't be able to block the Sun completely because
06:52of the satellite's changing orbit.
06:57Beyond the orbit of Neptune, there is the mysterious Kuiper Belt, filled with massy
07:02icy objects.
07:03The most curious thing about this space formation, though, is that the scientists failed to explain
07:08the pattern of its movement.
07:10The only explanation they have is that Neptune might be hiding a ginormous planet.
07:17This hypothetical planet has already got the name Planet Nine, and all we have to do is
07:22wait until its existence is confirmed… or not.
07:27The ocean on Jupiter is larger than any body of water on other planets of the Solar System.
07:32But it's not the ocean you think about.
07:35The one on Jupiter isn't made of water.
07:38This mesmerizing thing consists of metallic hydrogen.
07:42And its depth is around 25,000 miles, which is actually almost the same as the circumference
07:48of Earth.
07:51You got to know about beautiful Saturn's rings in the 1600s.
07:55But now we know that Saturn isn't the only ringed planet.
07:59All the giant gas planets – Uranus, Neptune, and Jupiter – have rings of their own, but
08:04they're thin and almost impossible to see.
08:08As for Mars, Venus, and Earth, they're made of rocky material and have no rings.
08:14At the same time, Saturn's moon Rhea might have a ring system consisting of three narrow
08:19bands.
08:20If astronomers manage to confirm it, it'll be the first time for people to discover rings
08:25around a moon.
08:28And Mars might get a set of rings of its own in the next 70 million years.
08:33The Red Planet's largest moon, called Phobos, is orbiting closer and closer to the planet.
08:39One day it's likely to get broken apart by the gravitational pull of the Red Planet
08:44and turn into a ring that can last for millions of years.
08:48And another cool fact about Mars – you've probably heard of methane gas, a byproduct
08:53of such natural processes as volcanic activity and cow emissions.
08:58Anyways, this gas is not only a part of the Martian atmosphere, but also the thing that
09:03confuses astronomers to no end.
09:06The thing is that the volume of methane on Mars keeps wavering, and scientists just can't
09:12figure out where it might be coming from.
09:14Can there be life on Mars?
09:16Can there be cows on Mars?
09:19That's it for today!
09:20So hey, if you pacified your curiosity, then give the video a like and share it with your
09:25friends!
09:26Or if you want more, just click on these videos and stay on the Bright Side!
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