Astronomers have already discovered about 800 confirmed expolanets in our universe, with thousands more still awaiting further investigation. But even among a crowd like that, there are standout finds. Scientists have just found the closet exoplanet to Earth yet, and it might not be alone.
The planet, designated Alpha Centauri Bb, was discovered by a research team from the Geneva Observatory and Portugal's University of Porto. It's so named because it was found near the sunlike star Alpha Centauri B, part of a three-star system that also includes Alpha Centauri A and Proxima Centauri. At 4.3 light-years away, it's the closest exoplanet to Earth that we've ever found, and it's remarkably Earth-like in size, but it seems that there the comparisons stop.
See, while Earth is orbiting 93 million miles away from our sun, in the "habitable zone," Alpha Centauri Bb is only 3.6 million miles from Alpha Centauri B. That mean's it hot. Damn hot. Surface temperature of 2,240 degrees Farenheit hot. That makes it rocky, possibly lava-covered and just plain uninhabitable. But scientists are still encouraged, not just because of the planet's proximity to Earth, but because there's a good chance they might be able to locate others in the same three-star system.
"Most of the low-mass planets are in systems of two, three to six or seven planets, out to the habitable zone," said Stephane Udry of the Geneva Observatory, who co-authored a study on the planet published this week in the journal Nature. Udry added that the discovery "opens really good prospects for detecting planets in the habitable zone in a system that is very close to us. In that sense, this system is a landmark."
There's still more work to be done confirming Alpha Centauri Bb's status, but its discovery has ensured that the system is about to get a lot more scientific attention, which could lead to the discovery of habitable planets sometime soon. But could we ever visit them? Maybe not, but according to researchers, it would at least be easier than most interstellar treks we could imagine.
"If you want to envision exploring this system, then it's almost twice as easy to get there as anywhere else," said Greg Laughlin of the University of California, Santa Cruz. "This is our backyard, and to find out that planet formation did occur there is just extraordinarily exciting."