A good basic description of surface planetary research provided by Brown University

A good basic description of surface planetary research is provided by Brown University's web site. On it they discuss impact craters, volcanism, plate techtonics and how a study of various planets has helped to understand the processes involved across planets. They also discuss remote sensing techniques and how they apply mass spectroscopy to meteorites and other geologic samples. One interesting thing I read about Venus is it is a good model for understanding what will happen to our planet if we lose our atmosphere and as a way to understand the "greenhouse effect" because Venus' atmosphere is largely carbon dioxide with clouds of sulfuric acid droplets. I was reading the Roger Tory Peterson Field Guide to the Stars and Planets written by Donald H. Menzel and Jay M. Pasachoff.

Earth-Moon-Mars, not playing from the same deck

Cosmology deals with the formation of the universe, but a subset of the same study looks as planetary formation. Current studies of silicates are showing that the Earth, Moon and Mars were formed under different conditions and explains some of the differences in mass. The moon is believed to be a planet that crashed into earth and the resultant rebound produced it from the upper portion of the earth, mostly made of silicates. This helps to explain why the Moon doesn't have the same iron core and is much lighter than the Earth. Well, Mars also has an iron core, but the silicates aren't of the same type as Earth. Just goes to show that we're still learning much from and about our solar system.