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Joshua E. Barnes
(barnes@ifa.hawaii.edu)
Last modified: September 26, 2006 http://www.ifa.hawaii.edu/~barnes/ast110_06/homework/disc04.html |
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One common confusion involved age. All planets in our solar system are the same age -- about 4.6 billion years old. However, ages of surfaces can be very much less than this figure.
Another confusion involved effects of atmosphere on number of impact craters. Our atmosphere protects us from small stuff, but even the thick atmosphere of Venus can't protect that planet from large impacts! The difference in crater density on Venus, Earth, and Mars indicates relative age of surface, not effect of atmosphere.
| Venus | Earth | Mars | |
| Impact Craters |
Few -- young surface Golubkina |
Few -- young surface Manicouagan, Barringer |
Many -- old surface Schiaparelli, Huygens Hellas (impact basin) |
| Volcanic Features |
Very extensive; planet resurfaced Maat Mons Maxwell Montes |
Common at plate edges, hotspots within plates Rainier (strato) Mauna Loa (shield) |
Many in some areas Olympus Mons |
| Tectonic Features |
One plate (thick?), two `continents': Ishtar, Aphrodite |
Mobile plates -> drift, rifting, subduction Mt. Everest San Andreas fault |
No active plates Tharsis bulge (uplift) Valles Marineris |
| Erosion | Limited; no water, stagnant atmosphere |
Extensive water erosion, active weather systems Grand Canyon |
Ancient water erosion, violent dust storms Ares Vallis (outflow) |
|
Joshua E. Barnes
(barnes@ifa.hawaii.edu)
Last modified: September 26, 2006 http://www.ifa.hawaii.edu/~barnes/ast110_06/homework/disc04.html |
|