astro 108

 The Earth has had three distinct atmospheres over its life to date. Describe the

      composition of these atmospheres and when they occurred.

            

 

 The same process responsible for the relatively young average age of rocks on the Earth is also responsible for the fact that we have so few craters. Names this process and describe how it works.

           

 

 

3.   What is the source of the magnetic field that we have on Earth?           

 

 

 

 Describe two physical features of Venus that are very rare in the solar system or unique to Venus. Also discuss their cause.

 

 

 What are the main indicators that there was once a liquid surface water on Mars?

 

 

 

       Describe and locate any current forms of water on Mars?