Astronomy 100

Section 2, Fall 2008

Homework G

Due Wednesday, October 29

On your scantron fill out your NAME, STUDENT NUMBER, and NETWORK ID both in writing and in the bubbles. In addition, fill out "FORM G."

1. Most of the asteroids are found between
a) Mercury and Venus
b) Jupiter and Saturn
c) Neptune and Pluto
d) Mars and Jupiter
e) Jupiter and Saturn

2. Whether called a planet or not, Pluto really belongs to
a) the asteroid belt
b) the Kuiper belt
c) the Oort cloud
d) Jupiter's family of comets
e) the family of Earth-crossing asteroids

3. Almost all meteorites come from
a) the Moon b) comets c) asteroids d) Mars e) Jupiter

4. Metallic asteroids are made mostly of
a) silicon
b) carbon
c) nickel
d) titanium
e) iron

5. Why are the inner planets made out of heavy materials?
a) they are close to the Sun and were hot
b) they are small
c) they were hit by comets, which blew away much of their primitive matter
d) they were rotating too fast to retain light materials like hydrogen
e) the gravity of the Sun was strongest in the inner Solar System, so it could drag in heavier materials

6. Amino acids and diamonds are found in
a) Moon rocks
b) Meteorites from comets
c) iron meteorites
d) stony meteorites called carbonaceous chondrites
e) nothing

7. Comets have two tails, one made of gas, the other of
a) asteroids
b) meteorites
c) dust grains and fluffy rocks
d) meteors
e) ions

8. Where do the gas tails of comets point?
a) toward the Sun
b) away from the Sun
c) toward the Earth
d) away from the Earth
e) back along the orbit

9. Short-period comets tend to
a) stick to the plane of the ecliptic
b) stick to the plane of the celestial equator
c) be found all over the sky
d) be found mostly inside the orbit of the Earth
e) be found orbiting Jupiter

10. A typical diameter for the nucleus of a comet is
a) 10 centimeters
b) a few to a few tens of kilometers
c) 10,000 kilometers
d) 10 millimeters
e) 1 AU

11. Comet nuclei are made mostly of
a) gas
b) the solar wind
c) iron
d) asteroids
e) ice and fluffy rock

12. Where do long-period comets come from?
a) the Kuiper belt
b) the Oort Cloud
c) the asteroid belt
d) Saturn's ring system
e) Other stars

13. Why did the asteroids not make a planet?
a) Jupiter's gravity kept them stirred up
b) They did make a planet, but it was smashed by our Moon on its way to the Earth
c) Asteroids are made from gas, so they could not assemble
d) Heat from Jupiter kept melting any planet that tried to form
e) The solar wind kept sweeping away the dust needed to make them adhere together

14. Most meteors are from
a) the Moon
b) asteroids
c) comets
d) the northern lights
e) other stars

15. Where do we believe most of the Earth's water came from?
a) asteroids
b) the Earth's center
c) the Sun
d) the collision that formed the Moon
e) comets

16. The terrestrial planets (and the cores of the giant planets) almost certainly accumulated from
a) interstellar molecules
b) gas in the solar nebula (the dusty gaseous disk that circulated around the early Sun)
c) dust grains in the solar nebula
d) the debris of a collision between the early Sun and a passing star
e) all of the above

17. Comets had to be formed
a) in the outer Solar System where it was cold
b) on the Moon and then ejected by asteroid impacts
c) on the Sun from condensing water
d) in interstellar space long before the Solar System was born
e) from the collisions between asteroids

18. The "Perseids" are
a) comets
b) meteorites
c) meteors in a shower
d) asteroids
e) an 80s rock band that sang astronomy songs

19. What populated the Oort cloud?
a) comets entering from other planetary systems
b) comets forming out there as a result of low temperature
c) the large outer planets throwing comets out of the early planetary system
d) the terrestrial planets throwing comets out of the planetary system
e) the collision that formed the Moon and present Earth

20. Which statement is evidence that the planets formed from a disk around the Sun?
a) All planets are made mostly of hydrogen and helium
b) There is no such evidence
c) All the planets orbit the Sun in a well-defined disk and all in the same direction
d) Craters on the Moon and Jupiter
e) Rotation speeds of planets decrease from Mercury outward

21. The Sun is how many times more massive than Jupiter?
a) 10 b) 100 c) 1000 d) 10,000 e) 100,000

22. The Sun is made mostly of
a) gaseous hydrogen and helium
b) water
c) oxygen, nitrogen, and carbon
d) light metals like calcium and sodium
e) liquid molecular hydrogen

23. The diameter of the Sun is about
a) 860,000 miles
b) 1.5 million km
c) 109 Earth diameters
d) 0.01 AU
e) all of the above

24. The temperature of the solar photosphere (the optically visible "surface") is about
a) 1000 K b) 6000 K c) 10,000 K d) 20,000 K e) 60,000 K

25. What causes the solar granulation?
a) radiation
b) convection
c) magnetic fields
d) electric currents
e) rotation