Download Putting a Spin on the Solar System

NAME: ________________________________ DATE: _________ HOUR: _________Table ______
Modeling the Solar System
The "Big" Picture - What's in the Universe
Scientists define the universe as all of space and everything in it. Nobody knows exactly how big
the universe is because nobody knows where it ends. Scientists think the universe is expanding outward in
all directions.
When you look up in the sky at night you can see hundreds of tiny pinpoints of light. These
seemingly tiny dots of light are actually huge spheres of glowing gas made of mostly hydrogen and helium
called stars. They look tiny because they are so far away. If you want to get a closer look at a star, all you
have to do is observe the sun. (Well, don't look directly at it. You might hurt your eyes.) The sun is one of
the many stars in the universe. It looks big to us because it is so close, but actually it is just a medium-sized
star. There are many other stars in the universe that are much bigger and brighter.
All of the stars in the universe are arranged in huge structures called galaxies. Each galaxy contains
billions of stars. There are billions of galaxies in the universe. Amazing! It sort of hurts your brain just
thinking about it! Our star, the sun, is located in a galaxy named the Milky Way. The next nearest galaxy
is the Andromeda Galaxy. If you started today and traveled at the speed of light it would take you about
two million years to get to the Andromeda Galaxy!
Many stars in the universe are known to have objects called planets in orbit around them. A planet
is an astronomical object orbiting a star that does not make its own light. Any star and the planets in orbit
around it are known as a solar system. Our planet, Earth, is a part of the solar system that includes our sun
and the nine planets that are in orbit around it. Other objects in our solar system include comets, asteroids,
and natural satellites called moons that orbit many planets.
A comet is a ball of ice and dust that travels around the sun in an elliptical (oval) shaped orbit.
Comets have a "tail" which is a trail of gas and dust radiating from the comet that points away from the sun.
Asteroids are big chunks of floating space rock in orbit around the sun that are too small to be considered
planets. Most of the asteroids in our solar system can be found orbiting in an area between the orbits of
Mars and Jupiter. This area has been named the asteroid belt.
Natural satellites, also known as moons, are solid objects found in permanent orbit around a planet.
Moons come in all sizes and usually have solid or rocky surfaces. Seven of the nine planets in our solar
system have moons in orbit around them. Some planets such as Jupiter and Saturn have many moons. So
far scientists have discovered at least 30 moons orbiting each of these planets. Uranus and Neptune also
have multiple moons, though not as many as Jupiter and Uranus. Mars has two tiny moons and Earth has a
single moon. The two closest planets to the sun, Mercury and Venus, have no moons at all.
Draw a model of the planets in order from the sun. Be sure to label the planets. Don’t forget the
asteroid belt.
S
U
N
NAME: ________________________________ DATE: _________ HOUR: _________Table ______
The Planetary Line-up
There are eight known planets in our solar system. In order from the sun outward they are:
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The planets have different
compositions, are different sizes, and are found at different distances from the sun.
Using Chapter 19 (page 644), sketch a picture of the planets in the space below. Watch the sizes!
1. What type of pattern do you notice in the size and distance of the nine planets in your model?
__________________________________________________________________________
__________________________________________________________________________
2. The planets in our solar system are made from either solid rock or thick, dense gases. Look at
your model. Make a guess as to which planets are made of rock and which planets are made of gas
based on your model. Use your model to explain your guess.
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
NAME: ________________________________ DATE: _________ HOUR: _________Table ______
Who's "In" and Who's "Out?"
Scientists studying the solar system saw the same patterns that you saw in your model. They
discovered that planets were made from either of two basic types of matter. Some planets are composed of
mostly rock and metal and have solid rocky surfaces. These are called terrestrial planets. Other planets
are composed primarily of thick, dense gases and do not have solid surfaces. These are called gas giants.
Scientists also noticed that there were four smaller planets located close to the sun and close to one another.
They observed that the rest of the planets (except Pluto) were very large, farther away from the sun, and
farther away from each other. Using this information, two basic groups of planets have been identified.
The first group is designated as the inner planets. Mercury, Venus, Earth, and Mars are the inner
planets. These are the four planets closest to the sun. The inner planets are all terrestrial planets because
they are made of rock and have solid surfaces. These planets are relatively small and are generally very
dense. The inner planets have few or no moons and do not have rings. Mercury, Venus, Earth, and Mars
are all relatively close to the sun. The orbits of these four planets take up only about 1/25 of the entire solar
system. The inner planets get energy from the sun.
The other group of planets is designated as the outer planets. Jupiter, Saturn, Uranus, and Neptune
are the outer planets. The four outer planets are all gas giants. They are made mostly of gas and do not
have solid surfaces. The gas giants are huge when compared to the inner planets. The largest planet,
Jupiter, is more than ten times larger than Earth. Even though they are larger, the gas giants are less dense
than the inner planets because they are made of gas. Gas giants all have visible rings around them. The
rings are made from chunks of ice, rock, and dust in orbit around the planet. Gas giants also have a large
number of moons in orbit around them. The gas giants are far away from the sun and there is a great deal
of distance between each of these outer planets. The gas giants are too far away to get much energy from
the sun. They get their energy from radiation created within the planet itself.
Pluto does not share most of the characteristics of the outer planets. It is a dwarf planet and has one
moon. The dwarf planet is small in size and is very dense. Pluto has no rings and does not make its own
energy. Since the new definition was created in 2006 Pluto was reclassified. The last part of the planet
definition, a planet has to dominate its region of space, excludes Pluto. Pluto is merely one of the larger of
many objects orbiting its region of space.
Putting a Spin on the Solar System
In order to understand the solar system and the galaxies beyond, you must first understand how
things in the universe move. Objects in the universe are in constant motion. Nothing ever stops
moving. It is important to grasp this concept in order to put together a picture of the way our solar system
works. There are two basic types of motion that explain the workings of the solar system. Both kinds of
motion are more or less circular because everything in the universe moves in circles, big and small. All of
the galaxies in the universe move in a continuous, gigantic circle. The stars in every galaxy swirl in a huge
circular pattern. The planets in the solar system orbit in a huge circle around the sun. The planets whirl on
their own axis as they make their way around the swirling mass of gas that composes the sun. All of this
motion is continuous and predictable, making it possible for us to study the solar system by observing the
pattern of its motion.
NAME: ________________________________ DATE: _________ HOUR: _________Table ______
1. Even though orbits are ellipses, what shape is a typical planet’s orbit most like?
A.
B.
C.
D.
A short rectangle
An egg-shape with a pointy end
A long, narrow oval
A circle
2. How is a moon different from a planet?
A.
B.
C.
D.
A moon is smaller than any planet.
A moon is less massive than any planet
A moon is in orbit around a planet.
A moon is unable to have an atmosphere
3. Which of these appears in Earth’s atmosphere?
A. A moon
B. A meteor
C. An asteroid
D. A comet
4. Which process occurs only when a small space object interacts with a larger space object?
A. Tectonics
B. Volcanism
C. Erosion
D. Impact cratering
5. Which processes occur because a planet or another space body is hot inside?
A. Tectonics and volcanism
B. Volcanism and erosion
C. Erosion and impact cratering
D. Impact cratering and tectonics
6. What do all four gas giants have that terrestrial planets do not have?
A. Atmospheres
B. Solid surfaces
C. Moons
D. Rings
7. What are the white stripes of Jupiter and the white spots of Neptune?
A. Clouds high in the atmosphere
B. Smoke from volcanoes
C. Continents and islands
D. Holes in the atmosphere