Planetary thrill

“I don’t know which I find more remarkable,” writes Lawrence Krauss in the current issue of Newsweek, “the fact that there appears to be a small rocky, Earth-mass planet orbiting the closest star to our sun, or the fact that astronomers were able to discover it.”

Because of its size, weight and that it is so close to Earth (4.2 light years away), the discovery of a new planet around the star Alpha Centauri B – and dubbed Alpha Centauri Bb – could be significant on two levels. The first is the technical ability to detect such planets and, if confirmed, what it means for finding other Earths in our own backyard, writes Krauss, a Foundation professor of physics and director of the ASU Origins Project.

Alpha Centauri Bb is so light, it barely tugs at its star causing the star to move back and forth only 50 centimeters per second. Measuring a star’s “wobble” is the way in which astronomers detect the presence of a planet. The fact that this wobble is so slight means the observation needed to be very precise and it needs to be confirmed by other independent teams.

If this discovery is validated, it could mean that solar systems are very common in the Milky Way galaxy, and “a galaxy full of potential Earths means things will never be the same,” Krauss states.