Download Solar System: Small Bodies

Name______________________________
Date______________
Balls of Rock & Ice
Between the orbits of __________________is a swarm of thousands of space rocks ranging from 900
kilometers (560 miles) across to microscopic grains of dust. This region is known as the ___________Belt
and it’s where most of the asteroids in the Inner Solar System reside. This is also where the dwarf planet
Ceres resides.
There are also countless thousands of _________in our solar system. These balls of ice and rock spend
most of their time far from the center of the solar system in one of two reservoirs: the ____________or
the ______Cloud.
The Kuiper Belt starts around the orbit of Neptune. It’s actually kind of a wedge shape wrapped
around itself into a donut with the thin edge facing in towards the Sun.
The Oort Cloud is much farther away. It really is a cloud—a globular swarm of deep-frozen shards of
matter left over from the formation of the Sun and the planets.
Asteroids:
Many asteroids, once called minor planets, are chunks of rock with odd shapes. They are too small to
have been rounded into spheres by __________. Other asteroids are nickel steel. At least a few other
asteroids are cores of dead comets. Main belt asteroids are made of primitive material from the early
history of the solar system.
Astronomers once thought that the Main Belt was the debris ring left over from a destroyed__________.
It’s much more likely that such a planet was, in fact, prevented from ever forming by Jupiter’s
strong gravitational pull.
In total, the mass of all the asteroids is less than that of Earth's moon. But despite their size, asteroids
can be dangerous. Many have hit Earth in the past, and more will crash into our planet in the future.
That's one reason scientists study asteroids and are eager to learn more about their numbers, orbits and
physical characteristics. If an asteroid is headed our way, we want to know that.
Many asteroids lie outside the main belt. For instance, a number of asteroids called Trojans lie along
Jupiter's orbital path. Three groups — Atens, Amors, and Apollos — known as near-Earth asteroids orbit
in the inner solar system and sometimes cross the path of Mars and Earth.
Starry Skies Questions:
#1 Where are the asteroids?
a) How can you tell the asteroids from the background stars?
b) Where in the solar system are these asteroids located?
Solar System: Small Bodies
Starry Skies Questions:
#2. A minor planet!
a) Describe the position and shape of Vesta’s orbit:
b) How fast is Vesta moving? Compare its speed to the other planets shown.
c) How long does it take Vesta to go once around the Sun? (hint: use years & months)
#3 How flat is the orbit of the asteroids compared to the planets? Describe!
Background:
The location, motion, and composition of the asteroids hold clues to the formation and history of the
solar system. The asteroids, or minor planets, formed at the same time as the rest of the system. The
material that makes up an asteroid is little changed from the early days because it was never incorporated
into the body of a full- fledged planet.
#1. How or why is material changed that is incorporated into a planet?
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Purpose: Asteroids are often described as potato-shaped. In this activity you will make observations and
measurements of a potato and extend this to the physical nature of asteroids just as astronomers
do with the real objects.
Materials: potato, balance, string, ruler, water, volumetric can, beaker, graph paper
Procedure:
#1. Examine the potato and draw a detailed map showing all its markings. The map would include
all sides. The drawings will be done on graph paper.
#2. Take the following measurements for the potato and record the results in the table:
Mass
Volume
(water
displacement)
Density
(D= M/V)
Width
Length
Circumference
(long axis)
Circumference
(short axis)
Name_______________________________
Discussion/ Analysis:
#1 What was the range of masses for the potato asteroids in the class?
#2 Did all the potatoes have the same or very similar density? How can you account for this result?
#3 Why would astronomers make detailed pictures of asteroids? How would that be useful?
#4 If you were required to determine surface area of your “asteroid” how could you do that?
Describe briefly!
#5 The largest known asteroids are spherical! This means they have the lowest surface-area-to- volume
ratio. Why would these asteroids have a spherical shape?