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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 earths 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 earth
and one of only five planets you can see
from 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
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
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 look 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
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 is just right
as far as we know earth is the only
planet to have living things
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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
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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
it is called this because it is really
big and made mostly of gases
jupiter is so big that you would have to
place 11 earths 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
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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
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 60 moons
orbiting around it some as large as the
planet mercury and many 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 sink
saturn is the farthest planet that can
be seen from earth without the help 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
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 give it its lovely color
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 takes it a very very long time to go
around the sun
remember mercury that only takes 88 days
to go once around the sun
poor neptune takes over 164
years to finish in 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 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 six dwarf planets in
the solar system and possibly many many
more
that leaves us with eight 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