Planet discovery raises hope of solar system like our own

Astronomers have discovered a planet resembling Jupiter orbiting a Sun much like our own 90 light years away, raising hopes of finding other planets similar to Earth outside our solar system.

Astronomers have discovered a planet resembling Jupiter orbiting a Sun much like our own 90 light years away, raising hopes of finding other planets similar to Earth outside our solar system.

The find brings the number of "extrasolar" planets detected so far to 115 since the first in 1995. But, significantly, the latest most resembles our own solar system, implying that there are planetary systems of a similar nature - and perhaps even with life - in our stellar neighbourhood.

Announcing the discovery by a British-led team of astronomers, Hugh Jones, from Liverpool John Moores University, said: "This planet is going round in a nearly circular orbit three fifths the size of our own Jupiter. This is the closest we have yet got to a real, solar system-like planet." Alan Penny, of Oxford University's Rutherford Appleton Laboratory, said the find was "a substantial step on the way to finding another Earth".

The newly found planet is about twice the mass of Jupiter, which itself has a mass 318 times greater than Earth. It orbits its star, designated HD70642 and situated in the southern constellation Puppis, at a distance similar to Jupiter - about 3.3 times further than the Earth from the Sun. It takes six years to circle its star; Jupiter takes nearly 12.

The new planet is too small and dim to be observed directly. The astronomers used a technique that watches for the "wobble" in a star's light, caused by the gravitational pull of unseen orbiting objects, such as planets. The find demonstrates that the team can detect "wobble" of just 3 metres per second across a distance of 830 billion billion kilometres.

Dr Penny said the "exquisite precision" of the instruments was what allowed the search for these planets. "Perhaps most stars will be shown to have planets like our own solar system," he said.