Stephen Hawking - Aliens

I think we should explore places where life potentially does exist, like Europa, to see if we can find signs of life elsewhere, with an extra focus on trying to find new places for us to inhabit. We need to spread to survive. Even if we were to terraform Mars or something, we need to continue to spread even outside of our galaxy. What if something were to happen to our sun?

KA,

While I think searching for extraterrestrial life is fantastic, I don't see any real practical value to it. Not to say that I disagree with you -- I agree with you wholeheartedly, but in a society which places so much emphasis on practical results, how would you justify an expedition costing billions of dollars for a discovery whose practical benefits are uncertain at best? Say that you were a notable advocate for searching for life outside of our planet. What would you say to convince the rest of us that this is a good idea?