Solar system's twin found

Astronomers have found a planetary system similar to ours - a Jupiter-like world circling a Sun-like star in roughly the same orbit that Jupiter follows our Sun. Of the 100 or so other planetary systems known, this one more closely resembles our than any other. Reporting this, the BBC science editor Dr. David Whitehouse says that researchers speculate that this system may contain other worlds, such as smaller rocky planets like Earth, either in orbit around the star or around the Jupiter-like world itself. The planet's parent star, called HD 70642, is too faint to be seen with the unaided eye, but is easily visible in the southern sky using binoculars. At just 95 light-years away (a light year is equal to 9,500,000,000,000 kilometers) the gas giant planet, bathed in the light of a yellow-dwarf star is on our galactic doorstep.

Like Jupiter, its atmosphere could be mottled and streaked with wind patterns and weather systems. Dark red methane clouds may scurry across its face beneath a high altitude frosting of bright ammonia crystals. At its poles, aurora may glisten and lightening bolts pulse across its night-time face. The planet detected orbiting HD 70642 is not the first Jupiter-class world to be found circling another star. All the planetary systems found so far contain gas giants like Jupiter. But the Jupiter like world stirs memories. It circles its parent star at a distance of 467 million kilometers (290 million miles), not a lot different from 778 million kilometer (483 million miles) that Jupiter is away from our Sun. The similarities do not end there. This new world circles its star every 6 years; our Jupiter takes 12 years.

Intriguing certainly, but the interest in this system is not principally because of what we know is there, but rather because of what else we suspect may be lurking unseen around the star and its planet. There could be other worlds smaller and rocky - possibly Earth-like. These are below our detectability.

"This is the closest we have yet got to a real Solar System-like planet, and advances our search for systems that are even more like our own" says Hugh Jones of Liverpool John Moores University, UK, who helped to discover the new world. The planet was found using the 3.9-metre (12.8 foot) Anglo-Australian Telescope in New South Wales, Australia. The discovery is being announced at a conference in France. Prior to the discovery of planets circling other stars, it was predicted that other planetary systems would be similar to our solar system - giant planets orbiting beyond 4 Earth-Sun distances in circular orbits, and smaller, rocky worlds in inner orbits.

But it turned out to not be like that. Planetary systems are much more diverse than anyone imagined, concludes the BBC science editor.