4. Briefly describe the structure of an atom. How big is an atom? How big is the nucleus compared to the entire atom? An atom consists of a nucleus and an electron cloud. The nucleus consists of protons and neutrons. Protons are a positive charge while neutrons have no charge. The electron cloud consists of electrons that have a negative charge. Atoms are so small there could be more atoms in a single drop of water than there are observable stars in the universe. 13. How do we think the moon formed, and what evidence supports this hypothesis? It is believed that there was a great impact between the earth and a huge planetesimal. The debris leftover from the impact went around the earth and formed the moon as we know it today. 18. Based on the known extrasolar planets, should we conclude that earth-like planets are rare? Why or why not?
I would say earth like planets are very rare. There are no other planets that humans can survive on without an enclosure. The conditions on earth are just right for life while other planets are not fit for life because of their brutal conditions. Ch. 7
9. How do crater counts tell us the age of a planetary surface? Briefly explain why the moon is so much more heavily cratered than the earth.
Unlike earth, the moon has no atmosphere. Because of the no atmosphere, meteors and meteorites hit the moon. Also there are traces of lunar maria which is lava from old volcanoes that cooled. 10. Briefly summarize the geological history of the moon. Be sure to explain the origin of the lunar maria.
After the moon formed, it started with some volcanism and techtonics. After some eruptions the moon cooled down and became what it is today. The lunar maria came from the cooled lava. Then as time went on the moon was hit by many impacts of meteors and asteroids. 12. Describe at least three similarities and three differences between earth and mars.
Some similarities that the moon and earth have is they...