Voyager 1 was launched in 1977. It's speed is approximately 38,000 miles an hour. It has left the solar system and is currently about 14.6 light HOURS from Earth. That's about .0017 light years. Alpha Centuri’s a LONG way away.
Yeah, and this is where it gets painful for me. I grew up with NASA and the thrill of seeing a moon walk. I remember the excitement of the early days of space exploration. I think, collectively, it's dawning on us that colonies on the moon don't make sense anymore than colonies on the bottom of the ocean or building a home on top of Mount Everest makes sense. You've got to have an umbilical cord back to earth, because you have to take everything you eat, breathe and drink with you. There's no mining or anything there that is remotely worth the expense of getting it and bringing it back.
In the end, it takes the efforts of millions of people (they're called taxpayers) to put three or four people out there. Going to Mars would require a phenomenal budget, and I suspect we'd find rocks. Considering even the closest star would require multigenerational commitments, and generations would be born and die on that ship and on earth during one trip. I can't imagine the real Space Family Robinson. We've got a reasonable idea of what's in our solar system, and the next step is a doozy, with no real reason, other than we'd like to go.
I don't discount scientific research from space exploration, but no one's made a compelling case as to how this would affect us.