Using what we have learned from life on Earth, what can we say about alien life? While it would probably be vastly different from life on Earth, alien life would probably adhere to certain universal guidelines, as the widely varying life on Earth does. These guidelines or ground rules include the following:
As you can see, life of any kind is intimately tied to its environment, so the characteristics of the planet would be extremely important in determining the characteristics of the life form.
Paul Davies, an astrophysicist at Arizona State University and chair of SETI's post-detection taskforce, argues that alien brains, with their different architecture, would interpret information very differently from ours. What we think of as beautiful or friendly might come across as violent to them, or vice versa. "Lots of people think that because they would be so wise and knowledgeable, they would be peaceful," adds Stewart. "I don't think you can assume that. I don't think you can put human views on to them; that's a dangerous way of thinking. Aliens are alien. If they exist at all, we cannot assume they're like us."