Star Trek

http://cosmiclog.nbcnews.com/_news/2013/04/18/17811465-super-earth-search-newfound-water-worlds-could-be-just-right-for-life?threadId=3707055&commentId=75654440#c75654440

Did you know that when a sun like ours is finished it won't collapse into a black hole but rather into a white dwarf.

A white dwarf is comprised of carbon and oxygen both of which the human body is made of and would not be if we didn't have a sun that eventually became a ball of carbon and oxygen.

http://blackholes.stardate.org/resources/faqs/faq.php?p=sun-become-black-hole

The closest white dwarf to Earth is only 8.6 light years away. This could mean that it would only take 8.6 years for oxygen and carbon particles to reach Earth. During the evolution of Earth which has been proven scientifically to have taken place over hundreds of millions of years means that the rate of carbon and oxygen permiation of Earth by the White Dwarf is consistent with the time line of the creatures on Earth evolving.

http://www.spaceref.com/news/viewpr.html?pid=18508

What this means is that Earth could have received the carbon and oxygen life needed from this white dwarf while our sun fueled other processes that created life on planet Earth.

I would suggest that NASA focus on white dwarfs and then look for planets that are within a range of 5 to 20 light years for planets that revolve around a

sun. That would be the best guess for finding a habitable planet like Earth.