Water came from the same place as on earth...formed while the planet was forming and cooling.
2) How long would it take to sublimate into the atmosphere?
Not sure. It's a long gradual process. Unfortunately, Mars' smaller mass seemed to be unable to entrap most of it.
3) Was Mars warmer long ago?
Absolutely. All the planets were.
4) If Mars has 95% CO2, what would its temp be without that greenhouse gas?
CO2 isn't a greenhouse gas according to much recent thinking. Besides, the atmosphere of Mars is very thin. Anyway presumed greenhouse effect would then be very small.
5) Where did the C02 come from?
Same place the water did.
6) Is there geothermal heat on Mars?
Possibly but not as much as Earth
7) Why are all the planets so different, surely they must have come from some homogenous planetoid material in the past? Why didn’t the mass all settle into one or two Super planets orbiting the Sun?
Great question that requires a long answer. All the planets formed from the same accretion disk but at different distances from the Sun. That meant different amounts of forces acting on them so different types of planets. http://stardate.org/resources/ssguide/planet_form.html
There are some good documentaries on Science channel.
8) shouldn’t the planets rocks be similar, with the major differences being the relative differences in heating, and time at certain temperatures?
In a way, they are. The rovers found very similar rock formations and types.
9) Could hexagonal shapes be due to other chemicals beside water? What about hydrogen sulfide? or frozen C02? How about heated magma, coming to the surface and crystallizing out?
Maybe. But water obviously does it. When you hear hoof-beats, think horses not zebras.
10) Could DNA survive such a thin atmosphere with all the X, cosmic rays, and solar ionizing radiation?
Possibly. After all, we've found dinosaur dna fragments.
11) How much C02 escapes the atmosphere on Mars?
Don't don't know but Mars is 1/3 the mass of Earth so it is easier for light gasses to escape.
Are these questions answered in any astronomy textbooks?
Probably. :-)
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