Friday, July 17, 2015

Earth-like planets could exist in our nearest solar system; but they might be too hot to support life

Twin Earth-like exoplanets could exist in the Alpha Centauri solar system, just 4.3 light years away from the Milky Way.

Although the two planets are likely too close to their star – and therefore too hot – to support life, astronomers believe it suggests the beginning of a more extensive string of worlds. Some of which could support water.

Alpha Centauri is a binary system, meaning there are two stars close enough together that their gravitational interaction means they orbit a common centre of mass.

The first of the potential Earth-like planets is named Alpha Centauri Bb, because it orbits the smaller of the two stars, Alpha Centauri B.

It was first announced in 2012 when astronomers believed it to be a rocky world a bit larger than the Earth.

However, other scientists contradicted its existence entierly. Explaining that the evidence – which involved watching Alpha Centuri B for a slight wobble caused by the gravitational pull of a planet – wasn’t strong enough.

And so a team at Cambridge University have re-examined our neighbouring solar system using the Hubble Space Telescope.

The team watched the light from Alpha Centuri B, waiting for a dip that would indicate the passage of the supposed planet.

And what they saw suggested that a planet was there – but its orbit didn’t match up with the original data surrounding Alpha Centuri Bb – which is why some believe there could even be TWO planets.

“If you ask anyone working in exoplanets, they would all have a different opinion about the existence of Alpha Centauri Bb,” said the University of Cambridge’s Brice-Olivier Demory.

“We find in our data a single transit-like event that could be associated to another Earth-size planet in the system, on a longer period orbit.

“If you see one planet, the chance is there are other planets in the system,” Demory told New Scientist.

Scientists will struggle to accurately confirm the existence of these two planets, or any others nearby, with the current generation of telescopes.

However, around 2,000 exoplanets have been discovered in the known universe and if Alpha Centauri Bb does prove real, it will be the closest one to Earth.