Let's not get ahead of ourselves... it would be more accurate to say "NASA finds more planets that could potentially be of the right type to support life, as far as we can tell at the moment." The significance of the latest announcements isn't that we can be sure these specific planets are habitable, but that the confirmation that planets of this size do exist in stellar habitable zones strengthens the case that there could be many habitable planets out there, whether or not these specific ones are among them.
T J wrote:
I sure wich we could determin if there are planets around Alpha Centauri. A habitable planet there would be... well just the best thing ever in the history of everything!
We discovered a probable planet around Alpha Centauri B last year:
And the search for more continues, though it will probably require technology that won't be in use for a few years yet. As the Wikipedia article says, astronomers at Alpha Centauri B couldn't discover Earth using the kind of equipment we currently have.
The sad truth is that we're far, far away from where all the action is. The concentration of habitable worlds is closer to the center of the galaxy and we're out on the periphery well beyond plausible reach.
Actually we're more in the middle of the galactic disk than the periphery. The percentage of stars that could support habitable planets is probably lower the closer you get to the center due to the greater threat from supernovae and other astronomical hazards, but the numerical density of stars closer in is sufficiently greater that the lower percentage still probably adds up to a greater number of habitable worlds. But that is, of course, just our current best estimate, which could be revised upon further discoveries. Words like "truth" are too absolutist for a subject we know so little about.