The prospect of alien life existing in the universe got a further boost last night when NASA revealed the discovery of six planets orbiting a star like the Sun. 

Impression of new planets (NASA/Tim Pyle)

The new worlds, part of a whole new solar system around 2,000 light-years away, were detected by a planet-seeking space telescope called Kepler.

At the same time, NASA revealed that Kepler has mopped up another thousand possible planets around other stars that have yet to be confirmed.

Astronomers are delighted over the new confirmed planetary system because five of the planets are small, unlike most of the 500 found so far around other stars.

They were found in what has been labelled the Kepler-11 star system by scientists at the University of California.

The five small planets are in tightly-packed orbits that would fit inside the orbit of the Sun’s closest planet Mercury.

They range in size from 2.3 to 13.5 times the size of the Earth and spin round their home star in “years” lasting less than 50 days.

Because those orbits are in line with us, the planets were observed to make regular transits of the star like mini solar eclipses.

Scientists were able to calculate the size of the planets and what they are probably made of by observing changes in the brightness of the star as they passed in front of it. The sixth planet is larger and further out from the star, orbiting it every 118 days.

Team leader Jonathan Fortney said: “Of the six planets, the most massive are potentially like Neptune and Uranus, but the three lowest mass planets are unlike anything we have in our solar system.”

The discovery, reported in Nature, is the latest big find by Kepler which is keeping constant watch on thousands of stars in one small patch of the Milky Way centred on the constellations of Cygnus and Lyra.

Last month NASA announced it had found its first rocky planet – the smallest world discovered outside our own solar system – labelled Kepler-10b but swiftly dubbed Vulcan.

Alien-planets expert Dr Carole Haswell, of the UK’s Open University at Milton Keynes, told Skymania News: “This is a very significant discovery. In my mind, Kepler-11 has just become the most interesting star in our Galaxy!

“The bottom line is that this discovery makes it much more likely that low mass planets, like the Earth, are plentiful in the Milky Way.” Read Carole’s own recent blog entry.

The announcement of further possible worlds increases the number of candidate planets identified by Kepler so far to 1,235. Of these, 68 are approximately Earth-size, 288 are super-Earths, 662 are Neptune-size, 165 are the size of Jupiter and 19 are larger than Jupiter.

Of the 54 new planet candidates found in the habitable or Goldilocks zone of their stars, five are of similar size to the Earth.

NASA Administrator Charles Bolden said: “In one generation we have gone from extraterrestrial planets being a mainstay of science fiction, to the present, where Kepler has helped turn science fiction into today’s reality.”

Another star may have seven planets orbiting it, according to results from a separate Earth-based search. View a NASA video of the latest solar system below.

• Discover space for yourself and do fun science with a telescope. Here is Skymania’s advice on how to choose a telescope. We also have a guide to the different types of telescope available. Check out our monthly sky guide too!

©PAUL SUTHERLAND, Skymania.com

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