Download Astro 1 Levine Homework Solar System

Astro 1
Levine
KEY
Name:_____________________________________
Homework Solar System
Score: __________/21
Questions are 3 points unless otherwise specified.
1. If you were exploring a planet in the habitable zone of a star other than the Sun and
discovered oxygen in the atmosphere, what might you conclude about the presence or
absence of life on the planet?
Well, you have to be careful about concluding anything hastily. However, because
the oxygen in Earth's atomosphere was produced by life, it would be a reason to
be cautiously optimistic about the possible presence of life on this planet.
2. Why isn’t Pluto a planet? What is the one key thing that causes it to be classified as a dwarf
planet rather than a planet?
The key thing that caused Pluto to be reclassified as a dwarf planet is that it failed
to clear it's orbit -- there are many other Kuiper Belt objects orbiting in the same
general area as Pluto.
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Astro 100
Levine
Homework Solar System
3. What would have had to be different in the history of Venus and Mars for these planets
to be more like Earth? (6 points)
Venus:
If Venus had not developed the very dense carbon dioxide atmosphere, it would not
have the incredibly high heat levels, and might have been more like Earth. To be
habitable, it would probably also have had to retain enough rotation to have enough
magnetic field to shield it from solar wind, but the atmosphere is the key item.
Mars:
Mars needed to retain its magnetic field so that it could hold onto its surface water.
This likely means Mars would have needed to be a little bit larger, The lack of
magnetic field is thought to have lead to scouring of the atmosphere and
dissociation of the water molecules due to UV light from the Sun. Mars is not large
enough to hold onto the hydrogen and the oxygen bound into the soil.
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Astro 100
Levine
Homework Solar System
4. The Cassini mission is conducting some final flybys of Enceladus. Research the October,
November and December flybys here: http://saturn.jpl.nasa.gov/mission/flybys/ and read
up on Enceladus here: https://en.wikipedia.org/wiki/Enceladus .
What do you find most interesting or surprising about Enceladus?
For all three of these the answers are going to vary. There is no right or wrong
answer, you will get full marks if you choose something that is a real property of
Enceladus, Pluto of Ceres.
5. The New Horizons mission recently flew by Pluto and took the first up-close images of
the dwarf planet. Read about some of the discoveries here: http://www.nasa.gov/imagefeature/homing-in-on-nix-plutos-small-satellite
What do you find most interesting or surprising about Pluto?
6. The Dawn mission is currently investigating Ceres, the dwarf planet in the asteroid belt.
You can explore the Dawn mission and its investigation of Ceres here: http://
dawn.jpl.nasa.gov/
What do you find most interesting or surprising about Ceres?
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