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Chapter 18
Lesson 1
What Makes up the Universe?
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The universe is all of space and everything in it.
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A Galaxy is a system of dust, gas, and many
millions of stars held together by gravity.
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We live in the Milky Way Galaxy. The Milky Way is
shaped like a flat spiral.
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Astronomy is the
study of the Sun, Moon,
stars, and the other
objects in space.
The Solar System
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The Solar System includes the Sun, the planets,
their moons, and other objects.
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Gravity is the force that keeps Earth and other
objects in their orbits
The Sun is so massive that its gravity pulls the
planets toward it.
gravity video
Inner Planets
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Mercury
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Closest plant to the Sun.
Covered with craters or dents shaped like bowls
Mercury is extremely hot during the day and is very
cold at night because there is not an atmosphere to
keep in the heat.
The Mariner 10 is a space probe that visited Mercury in
1974. A space probe is a vehicle that carries cameras
and other tools for studying different objects in space.
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Venus
Venus rotates in the opposite direction than
Earth.
Venus has an atmosphere, but the clouds are
poisonous.
The clouds reflect the Sun’s light which
makes it one of the brightest objects in the
sky.
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Mars
4th planet from the Sun
Soil contains iron oxide, which gives it a reddishbrown color. Called the “Red Planet”
Has 2 moons
Mars video 10 minutes
Gas Planets
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Jupiter—5th planet from the Sun
Gas gaint—a planet made of mostly gases
Largest planet in our solar system
It is so large that if it was hollow inside all the other
planets would fit inside.
Has a large red spot which is actually a large storm.
Has rings that are very dark and can not be seen from
Earth.
Video on Gas Planets (2:13 minutes)
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Saturn 6th planet from the Sun
Is a gas giant
Has large rings. The rings are made up of
everything from dust to large boulders.
Galieo saw the rings from earth and thought
they were handles in the 1600’s
Has 34 moons.
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Uranus 7th Planet from the Sun
A gas giant
Rotates on its side
This is the largest planet you can see from earth
with out a telescope.
Atmosphere is made up of methane which is a
liquid and gives Uranus its fuzzy blue-green look
Has at least 27 moons
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Neptune 8th Planet
Smallest of the gas planets, but it is still very
large. It could hold 60 Earths inside if it was
hollow.
Has strong winds that blow huge storms across
the planet.
Has at least 13 moons. One of its moons is the
coldest body in our entire Solar System -235 C
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Magic School Bus Space Video (29 minutes)