UK astronomers have helped discover the most Earth-like planet ever found outside the solar system.
The remote world is orbiting a star 25,000 light years away and is the smallest yet known in the galaxy.
Unlike most of the 160 other giant, gaseous planets already found around other stars, it is believed to be a solid world like the Earth.
It may have a thin atmosphere and it is thought to be covered by frozen oceans with a surface temperature of minus 220 degrees Celsius. That is too cold for life as we know it.
The planet, currently labelled OGLE-2005-BLG-390Lb, is five times bigger than Earth. It takes ten years to orbit its parent star, a red dwarf five times smaller than our sun, close to the centre of our Milky Way galaxy.
It was identified by a flash of starlight using an amazing technique called microlensing that was predicted by Albert Einstein in 1912.
The gravitational pull of a dim object between the star and astronomers magnified its light and revealed the planet’s presence, though it cannot be seen directly.
Astronomers from around the world collaborated to discover the new planet, revealed in the journal Nature.
They included Professor Keith Horne and Dr Martin Dominik of St Andrews University, Scotland, Dr Nicholas Rattenbury, of Jodrell Bank, Cheshire, and Professor Michael Bode, of Liverpool John Moores University.
Professor Horne, who has previously found two other worlds, believes he will find some even more like the Earth.
He said: “Microlensing is the fastest way to find small cool planets.
“Our first three discoveries indicate that small cool planets are abundant. If we can deploy robotic telescopes at additional sites in the southern hemisphere, we can expect to find several more cool planets every year, which could include the first detection of extra-solar Earths.”
Commentary: Astronomers do not expect life as we know it to be able to survive on the new distant world.
But its very existence is a massive boost for the idea that we are not alone.
It wasn’t until the early 1990s that the first planets were detected orbiting stars other than our own sun.
Since then, the number discovered has soared rapidly to 160 and counting.
Until now we have mainly found them around the closest stars to us by measuring tiny wobbles in the starlight.
Now new techniques like Einstein’s microlensing are allowing astronomers to look much further afield.
And the conclusion is inescapable – there are planets everywhere. The first planets found have been mainly giant gassy bodies like our own Jupiter and Saturn. Now smaller planets, more like Earth, are being detected.
Our solar system is not unique. So why should WE be unique?
If the universe is teeming with planets then could it also be teeming with life?
© Paul Sutherland. Unauthorised reproduction forbidden.