Download What Makes Up the Solar System?

Unit 5 Lesson 2
Vocabulary

Solar System: A star and all the planets and other
objects that revolve around it.

Planet: A body that revolves around a star.

Satellite: A body in space that orbits a larger body.

Asteroid: A piece of rock and metal that orbits the
sun.

Comet: A ball of ice, rock, and frozen gases that
orbits the sun.
What Makes Up the Solar
System?
Where is Earth located in our solar
system?
Where is Earth located in our universe?
Scientist explain that the sun is the center
of the solar system. All the planets in the
solar system, including Earth, revolve
around the sun. The solar system is
located on the edge of the Milky Way
Galaxy, one of millions of galaxies in the
universe.
The Inner and the Outer Planets


Astronomers generally divide the planets into
two groups, the inner and outer planets. The
inner planets – Mercury, Venus, Earth, Mars –
are rocky and are usually much smaller than
the outer planets.
The gas giants – Jupiter, Saturn, Uranus, and
Neptune – are not as dense as the inner
planets. They have thick atmospheres
consisting mostly of hydrogen, helium,
methane, and ammonia. Pluto is the exception
among the outer planets, as it is rocky and
very small.
The Inner and the Outer Planets

Because of the distances of the planets from the
sun is so great astronomers use the astronomical
unit (AU) to measure distance. An AU is the
average distance between Earth and the sun (150
million km, or about 93 million mi).
The Inner Planets

The four inner planets are Mercury,
Venus, Earth and Mars. All the inner
planets are rocky and dense.
The Inner Planets
Mercury which is
closest to the sun is
about the size of
earth’s moon.
 Like the moon, Mercury
has no atmosphere and a
surface covered with
craters and dust.
 The side of mercury that
faces the sun is hot – (810
F). The side of the planet
that does not face the sun
is very cold – 290F

Mercury
Venus


Venus is the brightest
object in the night sky,
after the moon.
This planet is about the
same size as Earth.
Venus can become very
hot, – (860 F). It is even
hotter than Mercury
because its atmosphere
keeps heat from
escaping.
The Inner Planets

Earth’s atmosphere and
its liquid water make it
the only planet know to
support life. Earth’s
atmosphere keeps the
planet at temperatures at
which living things can
survive.
Earth
Mars is called the red
planet because of its
reddish soil. Its atmosphere
is mostly carbon dioxide.
It’s river valleys are
evidence that Mars once
had liquid water.
 Mars has the largest
volcanoes in the Solar
System.
 It also has dust storms that
can last for months.

Mars
The Outer Planets

Beyond the inner planets are the five
outer planets. In order from the sun,
they are Jupiter, Saturn, Uranus,
Neptune, and Pluto.
The Outer Planets


Jupiter is the largest
planet in the solar
system. It has a ring,
dozens of moons.
There is a huge storm on
Jupiter that has lasted for
400 years. This storm
has been named the
Great Red Spot.
Jupiter
Saturn is best known for
its rings, which is made
of ice, dust, boulders,
and frozen gases.
 Like Jupiter, Saturn has
dozens of moons.
 Jupiter and Saturn are
the only planets that can
be seen from a
telescope.

Saturn
The Outer Planets
Uranus also has many
moons and rings. This
planet rotates on an axis
that is tilted much more
than those of the other
planets.
 It appears that Uranus is
rolling around its orbit
rather than spinning.

Uranus
Neptune


Neptune has several
rings and moons and the
strongest winds in the
solar system.
Both Neptune and
Uranus are similar in
size.
The Outer Planets




Pluto is small and rocky, unlike the other outer
planets. It also has an unusual orbit. Sometimes
part of Pluto's’ orbit passes inside the orbit of
Neptune, making Neptune the farthest planet from
the sun at times.
Pluto’s moon, Charon, is nearly as big and the
planet itself.
Scientist claim that Pluto is not a planet because it
is unlike the other planets in the solar system.
Other scientists claim that Pluto and its moon form
a double planet, because they are the same size,
and they are made of very similar materials.
The Outer Planets


Scientists have
recently gathered
data that shows that
there might be a 10th
planet in the solar
system.
The discover,
Sedna, is the most
distant object from
the sun. Approx. 10
billion miles away.

Sedna is threequarters the size of
Pluto, so some
scientist argue that it
is big enough to be
a planet.
Asteroids and Comets

Between Mars and
Jupiter is the asteroid
belt. This is a ring
shaped region where
thousands of small,
rocky bodies called
asteroids are located.
Scientists hypothesize
that asteroids in the
asteroid belt are
pieces of what may
have been a planet
orbiting between Mars
and Jupiter.
Asteroids and Comets

Other pieces of rock that
travel through space are
called meteors. When a
meteors hits Earth’s
Atmosphere, it usually
burns up. This causes
the bright strike of light,
or “Shooting Star” that
you see in the sky.
Meteors
A comet may pass close to
the sun and then seen out
past the orbit of Pluto, to
the edge of the solar
system.
 Each time a comet
approaches the sun, it
changes. The center, or
core, of the comet begins
to melt. This forms a cloud
of gas that is pushed into a
long tail by energy from the
sun.

Comets
Asteroids and Comets

Many comets have been named for the
people who discovered them. One is
Halley’s Comet, which was last seen
from Earth in 1986. It will appear again
in 2061-2062 as part of its 76-year orbit
around the sun.