Planet similar to Earth discovered

Scientists have found the most similar planet to Earth so far discovered, which is only a little bigger and seems to be made of very similar materials.

Describing the results in Nature, two independent teams of scientists found the planet – which is 400 light years away – has a diameter of 9,200 miles (about 1.2 times that of Earth), a rocky interior and an iron core. However, Kepler-78b zips around its star every eight and a half hours at a distance of 1 million miles, and the surface temperature is probably at least 2,000 degrees higher than the hottest day on Earth.

The scientists used the transit method to determine the orbit and size of Kepler-78b: they watched the light given off by the parent star, Kepler-78, and noted how often and how much it dimmed every time the planet passed in front of it. Calculating the mass involved watching how its gravitational pull made the star wobble.

"This is a very important result, and goes to the question of how common planets like our own are in the galaxy," said Bill Chaplin, an astrophysicist at the University of Birmingham.

“Getting a good estimate of the size of the planet and a good estimate of the mass – is still very rare.”

Subhanjoy Mohanty, an astrophysicist at Imperial College London, said the discovery was an important step towards finding true analogues of Earth.

– (Guardian service)