Our Solar System
Our Solar System
Our Solar System, Have you ever looked up into the sky and wondered what was there? Higher than the birds, past the clouds, and farther than the moon. A whole host of fascinating objects spin in outer space.
Let's imagine for a moment that we can leave
the earth behind. and explore the solar system that surrounds it. We call it
the solar system because everything in it is centered around the sun, and solar
means something to do with the sun.
The sun is a star, just
like many of the stars that you can see in the night sky - just many times
closer to us. Still, the sun is very, very far away from the earth.
almost 93 million miles away: that's why it
looks so small. even though it's the biggest object in the solar system. In
fact, the sun makes up more than 99 percent of the mass in the solar system.
If you put all of the
planets, moons, asteroids, comets. and everything else in the solar system
together. They would make up less than one-quarter of a percent of it. The sun
is so big that it's more than 100 times wider than the earth. And if it were a
giant jar you could fit more than one million earth into it.
More than that, the sun is what holds the
solar system together. Its massive gravity is what keeps the earth and all the
other planets circling around it instead of drifting off into 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. Plants could not grow. Water would
freeze, and nothing could survive. The sun gives us heat and light because it is
always burning: it is a giant ball of gas, mostly hydrogen and helium, and it
burns at millions of degrees in its center. Let's leave the sun now 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 the earth, and one of only five planets you can see from the earth using nothing but your eyes.
Of course, it won't look much like a planet. It
looks more like a bright star, and many nights you can see it close to the horizon near sunrise and sunset. Mercury is a lot like our moon. It's small
and has a rocky surface with craters on it.It has no moon of its own, and no
air to breathe.
Our Solar System
You probably wouldn't enjoy a visit to
mercury, since temperatures are boiling hot in the sun and freezing cold in the
shade. Something interesting about mercury is that it is the fastest planet to
go around the sun - it only takes 88 days.
Venus:
Next is Venus, the
second planet. Some people call venus earth's sister because the two planets
are very close in size and gravity, but they 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 atmosphere of carbon dioxide helps it to trap the heat and stay
warmer than its neighbor. It has a thick atmosphere, but it is not one you
could breathe.
It is mostly made of
carbon dioxide and there are clouds of sulfuric acid! Venus might not be fun to
visit. But it is beautiful to lok at. It is the second-brightest object in the
night sky - the only thing brighter is the moon.
If you are looking at a sunrise or a sunset
and suddenly notice what looks like a very bright star. you are probably looking
at Venus.
Earth:
After Venus comes Earth, the third planet from
the sun. Of course, you know all about Earth, because that's the planet where
we live! Earth is what's called a 'goldilocks planet.' because it's not too
hot, and not too cold - it's just right.
As far as we know, Earth is the only planet to
have living things. Let's leave earth again for a moment, though, and visit
Mars, the fourth planet from the sun.
Mars is known as the 'red planet,' because
iron oxide (a material like rust) in the soil gives it a reddish color. Mars is
smaller than Venus and the earth, but larger than mercury.
It is cold and rocky,
with a thin atmosphere made of carbon dioxide and oxygen. There is water ice on
Mars. Scientists are very interested in mars because they think that people
could live there with the help of some special equipment.
Rockets and probes have already been sent
there to gain more information about the planet. Right now, there are two
special robots exploring the surface of Mars. sending information back to
earth.
Mars is the first planet we've visited today
besides Earth to have its own moons. It has. two, although they are not big and
round like our moon.
Mars's moons are small and irregular. Scientists
think they may be captured asteroids. Maybe they came from the big asteroid
belt that is between Mars and Jupiter.
An asteroid belt is a big ring of asteroids,
or rocky objects, orbiting the sun. Jupiter comes next, the fifth planet in the
solar system. Jupiter is the largest planet and is something called a 'gas
giant.'
. Jupiter:
It is called this because it is really big and, made
mostly of gasses. Jupiter is so big that you would have to place 11 piles of earth end
to end just to stretch across its middle.
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 towards it.
Jupiter has at least 67
moons that circle around it, but 55 of them are very small, only about 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 cannot land on
Jupiter because it is made of gas - there is no ground to land on! Even if
there was somewhere to land. Jupiter is covered by terrible storms, much
stronger than even the strongest storms on earth.
One storm that we know about can be seen from earth.
We call it the great red spot because that's what it looks like - and it has
been going on for at least 200 years.
Saturn:
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 from 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
much smaller. Something interesting about Saturn is that even though it is very
large. it is not very dense.
That means that if you could find a bathtub
large enough to put Saturn in, it would float instead of the sink! Saturn is the
farthest planet that can be seen from the earth without the help of a telescope.
Uranus:
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 spins 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 lovely color.
Neptune:
Very similar to Uranus
is Neptune, the eighth planet from the sun. Neptune is another gas giant, and
like Uranus, it has methane in its atmosphere so it also looks 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 about.
Because Neptune is so
far out in space. it makes it a very, very long time to go around the sun.
Remember Mercury, which only takes 88 days to go once around the sun? Poor
Neptune
takes over 164 YEARS to
finish an orbit around the sun.
The last time that Neptune was in the same
place it is now was before the American Civil War, before computers, phones,
airplanes. or cars had been invented! Neptune has the longest orbit of any
planet in the solar system.
Now, you may think that
I've forgotten someone - Pluto. Pluto was discovered in 1930 and was listed as
the ninth planet in the solar system. As it was studied 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. Plus, people started 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 of being listed as a planet. Pluto was declared a 'dwarf planet' to
show that it was something that was 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. Goodbye till next time!
Technology: Mercy or A dissonant
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