Exploring Our Solar System: Planets and Space for Kids - FreeSchool

You're watching Free School! Our Solar System Have you ever looked up at the sky and wondered what was there? Higher than the birds, beyond the clouds and farther than the moon, a large number of fascinating objects rotate in

space

. Let's imagine for a moment that we can leave Earth behind and explore the

solar

system

around it. We call it the

solar

system

because everything in it is centered around the sun, and solar means something that has to do with the sun. The sun is a star, like many of the stars that can be seen in the night sky, only much closer to us.

Still, the sun is very, very far from the earth; Almost 150 million kilometers away: that's why it seems so small, despite being the largest object in the solar system. In fact, the sun makes up more than 99 percent of the mass of the solar system. If you put together all the

planets

, moons, asteroids, comets and everything else in the solar system, they would represent less than a quarter of a percent of it. The sun is so big that it is more than 100 times wider than the Earth, and if it were a giant jar, more than a million Earths could fit in it.

More than that, the sun is what holds the solar system together. Its enormous gravity is what keeps Earth and all the other

planets

spinning around it instead of drifting in

space

. The sun is also what allows us to live on Earth. Without the sun there would be no heat. There would be no light. The plants couldn't grow, the water froze and nothing could survive. The sun gives us heat and light because it is always burning: it is a giant ball of gas, mainly hydrogen and helium, and it burns at millions of degrees at its center. Let us now leave the sun to explore the planets.

As we move away from the sun, the first planet we will encounter is Mercury. Mercury is the smallest planet in the solar system, much smaller than Earth, and one of the five planets that you can see from Earth using only your eyes. Of course, it won't look much like a planet. It looks more like a bright star and many nights it can be seen near the horizon around sunrise and sunset. Mercury looks a lot like our moon. It is small and has a rocky surface with craters. It has no moon of its own or air to breathe.

You probably wouldn't want to visit Mercury, as temperatures are very high in the sun and freezing in the shade. Something interesting about Mercury is that it is the fastest planet to orbit the Sun: it only takes 88 days. Next is Venus, the second planet. Some people call Venus Earth's sister, because the two planets are very similar in size and gravity, but are very different on the surface. First of all, it is very hot. Venus is the hottest planet in the solar system. It's not as close to the Sun as Mercury, but its thick carbon dioxide atmosphere helps it trap heat and stay warmer than its neighbor.

It has a thick atmosphere, but you can't breathe. It is mainly composed of carbon dioxide and there are clouds of sulfuric acid! Venus may not be fun to visit, but it is beautiful to behold. It is the second brightest object in the night sky; The only one brighter is the moon. If you're watching a sunrise or sunset and suddenly notice what looks like a very bright star, you're probably looking at Venus. After Venus comes Earth, the third planet from the sun. Of course, you know everything about Earth, because that's the planet we live on! The Earth is what is called a 'goldilocks planet', because it is neither too hot nor too cold: it is perfect.

As far as we know, Earth is the only planet that has living things. But let's leave Earth again for a moment and visit Mars, the fourth planet from the Sun. Mars is known as the "red planet" because the iron oxide (a rust-like material) in the soil gives it a reddish color. Mars is smaller than Venus and Earth, but larger than Mercury. It is cold and rocky, with a thin atmosphere composed of carbon dioxide and oxygen. There is water ice on Mars. Scientists are very interested in Mars because they believe that people could live there with the help of some special equipment.

Rockets and probes have already been sent there to obtain more information about the planet. At the moment there are two special robots

exploring

the surface of Mars and sending information back to Earth. Mars is the first planet we visit today, besides Earth, which has its own moons. It has two, although they are not large and round like our moon. The moons of Mars are small and irregular. Scientists believe they may be captured asteroids. Perhaps they came from the large asteroid belt between Mars and Jupiter. An asteroid belt is a large ring of asteroids or rocky objects that orbit the sun.

Next comes Jupiter, the fifth planet in the solar system. Jupiter is the largest planet and is something called a "gas giant." It is called that because it is very large and is composed mainly of gases. Jupiter is so big that you would have to lay 11 Earths end to end to stretch its center. Jupiter is also the third brightest object in the night sky; Only Venus and the Moon are brighter. You can usually find Jupiter higher in the sky than Venus, since Jupiter is away from the sun and not toward it. Jupiter has at least 67 moons orbiting it, but 55 of them are very small, as big as a mountain, or smaller.

Some of its moons are very large and at least two of them are about the same size as the planet Mercury. One of its moons is the largest moon in the solar system. Some of these large moons can be seen from Earth in your backyard with a telescope. People can't land on Jupiter because it's made of gas: there's no ground to land on! Even if there was somewhere to land, Jupiter is covered in terrible storms, much stronger than even the strongest storms on Earth. A storm we know of can be seen from Earth. We call it the great red spot because that's what it looks like, and it's been like that for at least 200 years!

After Jupiter comes Saturn, another gas giant. Saturn is famous for its beautiful rings. Although they look solid from a distance, the rings are actually made of many, many small ice particles, as well as rocks and dust. Saturn also has more than sixty moons orbiting around it, some as large as the planet Mercury and many smaller. Something interesting about Saturn is that although it is very large, it is not very dense. That means that if you could find a bathtub big enough to put Saturn in, it would float instead of sink! Saturn is the farthest planet that can be seen from Earth without the aid of a telescope.

After Saturn comes Uranus, the seventh planet from the Sun. Uranus is another gas giant, but it is much smaller than Saturn and Jupiter. Unlike any other planet in the solar system, it is tilted so much that it actually rotates sideways! Uranus has rings around it, although they are much smaller than Saturn's, and 27 known moons. Uranus is covered in blue clouds made of methane, which gives it its beautiful color. Very similar to Uranus is Neptune, the eighth planet from the Sun. Neptune is another gas giant and, like Uranus, has methane in its atmosphere, which is why it also appears blue.

Neptune is a darker blue than Uranus and scientists aren't sure why. Neptune has a few thin rings and 14 moons that we know of. Because Neptune is so far away in space, it takes a long time to orbit the Sun. Remember Mercury, which only takes 88 days to orbit the Sun? Poor Neptune takes more than 164 YEARS to complete one orbit around the sun. The last time Neptune was in the same place as now was before the American Civil War, before computers, telephones, airplanes or automobiles were invented! Neptune has the longest orbit of all the planets in the solar system.

Now you may think I've forgotten someone: Pluto. Pluto was discovered in 1930 and was listed as the ninth planet in the solar system. By studying it longer, scientists realized how small it is. It is much smaller than any other planet in the solar system, and even smaller than many other moons. Additionally, people began to discover other small, rocky planet-like objects in space near Pluto. Some of them were even bigger than Pluto! In 2006, after 76 years classified as a planet, Pluto was declared a 'dwarf planet' to show that it was something like a planet, but much smaller. There are at least 6 dwarf planets in the solar system, and possibly many, many more.

That leaves us with 8 official planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. I hope you enjoyed

exploring

the solar system with me today. See you soon!