It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
Compare the atmospheres of the terrestrial planets
Mission and latest findings of NASA’s space craft Cassini
Locate at least three (3) good sources to describe our understanding of your topic. You may cite your textbook but it will not count as one of your three. You will need to synthesize information from your research into your own words to explain why the topic is significant, what our current knowledge is, and what mysteries remain to be discovered.
Even though you cannot cite encyclopedia sources, they are a good place to start your research.
These types of sources will give you background information and the big picture (plus teach you any specialized jargon that might go with your topic) which will help you make better choices when you do your "real" research later on.