Some scientists think they’re likely to find an earth-like planet in the neighborhood (i.e., within a few light years) in the next decade or two. Obviously, it would be pretty neat if they do, but I think that they’re indulging in a little wishful thinking here:

Levinson says he believes the knowledge that another Earth exists will lead to a public clamor for more powerful space propulsion systems, ones that can carry probes to other stars in a few decades. ”I think that will be the real start of the space age, and everything we’ve done from the 1950s until now will be seen as a prelude,” he says.

I see no reason to believe this. There are a number of interesting planets in our own solar system that we need better propulsion to explore properly, and there’s been no notable public clamor for that. He’s going to have to look for a different motivation, and source of funds, if he wants to see starships. I think it will be done privately.