Quote Originally Posted by jimsumner View Post
The possibility of FTL travel is the key. In the absence of faster-than-light travel the only way interstellar travel makes sense is for a species that has an exceptionally long life span and the capability of building ships and artificial environments that last a really, really long time.
Not necessarily, because of relativity and time dilation. A spaceship that travels extremely fast, at almost but not quite the speed of light, could make it to other stars in the galaxy in thousands of years from our perspective, but in only decades from the perspective of a creature on board the spaceship. It sounds wacky, but note that time dilation and relativity have already been proven to be Real Things using very precise measurements.

But, this is all getting ahead of ourselves. The next step is to look for life in our Solar System. And I think it's totally realistic that we find strong evidence of microbial life on Mars, Venus, Europa, or Enceladus within our lifetimes.