Do you have any evidence that there’s a planet at Alpha Centauri that could support human life? Why would anyone go there?
(From Wiki):
The discovery of planets orbiting other star systems, including similar binary systems (Gamma Cephei), raises the possibility that planets may exist in the Alpha Centauri system. Such planets could orbit Alpha Centauri A or Alpha Centauri B individually, or be on large orbits around the binary Alpha Centauri AB. Since both the principal stars are fairly similar to the Sun (for example, in age and metallicity), astronomers have been especially interested in making detailed searches for planets in the Alpha Centauri system. Several established planet-hunting teams have used various radial velocity or star transit methods in their searches around these two bright stars.[70] All the observational studies have so far failed to find any evidence for brown dwarfs or gas giant planets.[70][71]
However, computer simulations show that a planet might have been able to form within a distance of 1.1 AU (160 million km) of Alpha Centauri B and the orbit of that planet may remain stable for at least 250 million years.[72] Bodies around A would be able to orbit at slightly farther distances due to A's stronger gravity. In addition, the lack of any brown dwarfs or gas giants around A and B make the likelihood of terrestrial planets greater than otherwise.[73] As of 2002, technologies did not allow for terrestrial planets like Earth to be detected around Alpha Centauri.[73] But theoretical studies on the detectability via radial velocity analysis have shown that a dedicated campaign of high-cadence observations with a 1-m class telescope can reliably detect a hypothetical planet of 1.8 Earth masses in the habitable zone of B within three years.[7
I daresay we'll know if there are planets long before we'd be ready to go.