Alpha Centauri’s Earth-Sized Planet

Science continues to achieve amazing advances in our ability to detect, measure, and analyze planets orbiting stars far outside our solar system.

So far, scientists have discovered and confirmed the existence of more than 800 planets.  Most of the planets, however, are huge gas giants, like Jupiter or Saturn in our solar system.  The latest advance in detection capabilities came this week, when scientists announced that they have detected the lightest planet to orbit a Sun-like star — and the star just happens to be Alpha Centauri, a weird, triple-star system that is the Sun’s nearest galactic neighbor.

Alpha Centauri, for those who fell asleep during astronomy class, is a mere 4.3 light years away.  Of course, one light year is 6 trillion (6,000,000,000,000) miles away, but who’s counting?  The planet scientists have detected is about the mass of our good Earth.

Before you start worrying that little green men might appear on your doorstep tonight, take a deep breath:  the Earth-sized planet is closer to Alpha Centauri B than Mercury is to the Sun, so it’s probably not conducive to life.  Still, the discovery is remarkable.  In the not too distant future, scientists will use this detection technology to find a planet about the size and mass of Earth, orbiting a star a lot like Sol, at a distance that would suggest that it is likely to be temperate.  What will that mean?  My guess is that we will train every radio telescope and sensory device we have in the direction of that planet, listen as hard as we can, and hope.