Asteroids
Name
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Asteroids
YBetween Mars and Jupiter there is a gap 0(300 million miles known as the Asteroid Belt. In the 18th
century a mathematician, J. D. Titius, discovered a mathematical relationship among the planets.
It was popularized by Johann Bode in 1772 as a game of numbers. Using this game of numbers,&
Piazzi in '1801 discovered Ceres in the asteroid swarm. Ceres is only 400 kilometers in diameter
and, therefore, too small to be called a planet. These bodies are often called minor planets, and it
is estimated that there are 40,000 or more of them. These asteroidal bodies are composed of rocks
and are irregular in shape. They contain neither dust norsoil. They may be a reddish colorordeep
black. Many are only a few kilometers in diameter at the widest part. They may have been formed
from remaining debris after the formation of the major planets or from a planet that long ago was
broken up. New minor planets or asteroids are being located often. Near Jupiter there is an area
without asteroids called the Kirkwood gap, first noted by the American mathematician Daniel
Kirkwood. This space exists because of the strong gravitational pull of Jupiter. Astronomers think
that these minor planets actually collide with other bodies in space. Perhaps our moon's craters
were caused by such a collision.
,
Crossword Puzzle: Use the reading selection above to help you solve it.
Across:
1. com position of asteroids
16
2. the largest known planet
1.
3. not found in asteroid S
[
15
4. large number of thin gs in motion
S. band
2
6. name of an asteroid
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.. 7. not major
17.
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8. color of asteroids
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9. celestial body betwe
en
6.
19.
Mars and Jupiter
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8.
10. creator of game
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of numbers
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I '--11. discovered Ceres
12. space
10.
11.
13. not found in asteroid s
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14. size and ~
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18.
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3.
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12
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Down:
3. waste
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6. pockets or holes
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on the moon
10 color of asteroids
15. huge area
16. mathematician who
discovered a gap
17. the red planet
18. come together with impact
19. physical shapes in space
13
1
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14
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Fill In the words to fit the definitions. Then re
arrange the circled letters to find the group name
for minor planets.
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-000
---000­
-00--0
4th planet from Sun
Named for ruler of Olympus
Heavenly
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Meteoroids/Comets
Name
Meteoroids, Meteors, Meteorites
Meteoroids are tiny pieces of rock moving in space. There are two kinds of meteoroids: shower ~
and sporadic. The shower of meteoroids move around the sun in swarms and when Earth passes
through a swarm, a shower of shooting-stars results. These showers are predlcteble but vary
greatly in radiance. As a result, some can be seen clearly and. others cannot be. Sporadic meteor­
oids occur often. Astronomers think that more than twenty million meteoroids come in the atmos­
phere every day, but few get closer than fifty miles tothe earth because they are so small and
disintegrate when they become nsatedby friction. The luminous streak seen in the sky is called a
meteor. A meteorite is a piece of material from space that lands on Earth. There are two kinds of
meteorites: siderites (made up mostly of iron) and aerolites (stones mostly of oxygen, iron, silicon, '
and magnesium). Some aerolites are composed of iron and nickel. One of the most famous is the
Sacred Stone in Mecca. In 1897, Admiral Peary in Greenland found the second largest meteorite.
Its name is Ahnighito. One can view it in New York at the Hayden Planetarium. The largest
meteorite is in Namibia, Africa. It is called Hoba West.
Complete the following:
'1. What is a meteoroid?
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2.
Why do meteoroids usually disintegrate ratherthan fall to Earth?
3.
Name the two kinds of meteorites and give the composition of each.
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(a)
(b)
4.
Namethreefamous meteorites:
(a)
(c)
(b)
5.
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What is the common name for the luminous streak of a meteor?
Comets
Comets are celestial bodies that vary greatly. They may' be brilliant or appear as a small area of
light that is blurry. They move in orbits but only the bright Halley's Comet has a cycle of 76years; it
is due to appear again in 1986. All others have a period of several centuries. A comet has a nucleus,
made up mostly of ice and a tail that is gaseous, appearing as a straight streak of light. The tail
may be made up of dust particles which causes the streak of light to appear curved. The tail usually
points away from-the sun because of solar wind. Contrary to popular opinion, astronomers say
there is no connection between meteorites and comets.
A. Answer these questions:
1. Of what two parts is a comet composed? (a)
(b)
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2.
3.
4.
What is solar wind?
Of what is the tail of a comet made? (a)
In what direction does thetail point?
B.
Write a report on HaIley's Comet. Although it can be seen in 1986 in Europe and North
America, it will be brilliant in Australia.
(b)
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