They had told us a particular supernova exploded 10,000 years ago. How then, did the Chinese see it in AD 185? The answer is a case study in scientific inference.

When speculating about life in the universe, scientists need to be more realistic than Hollywood. In Star Trek, no matter where the actors land, they can walk around and breathe the air. That may be easier on directors, but for a surface to be habitable, there are physical requirements.