A new twin

A new twin? Scientists announce most Earth-like world yet found - boosting chances in search for alien life

• Potential planet KOI 172.02 has a radius of 1.5 times that of Earth
• It orbits in its star's habitable zone - meaning it could host liquid water
• Nasa believes almost every sun-like star could have at least one planet
• 461 potential planets identified by the Kepler mission since February 2012
• Dramatic increase in number of Earth-sized planets

An alien planet spotted by Nasa's Kepler space telescope is the best candidate yet for an Earth-like world beyond our solar system, Scientists claim.

The planet - whose existence is yet to be positively confirmed. has a radius that is just 1.5 times that of our own and orbits in the 'habitable zone' of a star similar to our own Sun.

That means the planet would likely have a similar amount of gravity as Earth and liquid water could exist on its surface - making it a prime candidate to host alien life.

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Distant worlds: An artist's impression of Earth-like exoplanets

This artist's illustration represents the variety of planets being detected by NASA's Kepler spacecraft: Nasa astronomers have revealed the discovery of a potential planet that could be the closest to Earth yet found

'This was very exciting because it's our fist habitable-zone super Earth around a sun-type star,' said Nasa astronomer Natalie Batalha at the annual meeting of the American Astronomical Society this week.

The announcement comes after it was revealed at the same meeting that analysis of data from Kepler had shown there are 17billion planets in the galaxy that are Earth-like in size.

 

The possible planet is called KOI 172.02 - with the initial trio of letters standing for Kepler Object of Interest, a prefix given to all planetary candidates found by Kepler until their existence is confirmed.

Dr Batalha said the find had the potential to be the closest so far to an Earth-twin beyond the solar system. It orbits a G-type star that is only slightly cooler than our own Sun, she said.

'Previously the ones we saw were orbiting other types of stars,' she was quoted as saying by SPACE.com.

An artist's impression of Kepler-20e, one of the planets identified by the Kepler space telescope mission

Analysis of Kepler's data indicates that the object takes 242 days to orbit its star, from which it is about three quarters as distant as the Earth is from the Sun.

Astrophysicist Mario Livio, of the Space Telescope Science Institute in Baltimore, told SPACE.com that the find was a 'big deal'.

'It's definitely a good candidate for life,' he said.

Christopher Burke of the SETI Institute announced the discovery of the planet along with a batch of 461 new planet candidates spotted by Kepler since February last year.

Latest findings released by NASA show that since February last year there have been 461 potential new planets discovered.

These bring the total number of potential planets that have been identified by the Kepler mission to 2,740 and they orbit 2,036 stars.

A breakdown by size of potential planets identified by the Kepler mission.

Among the most dramatic increases is in the number of Earth-sized and super Earth-sized planets.

Discoveries of Earth-sized planets increased by 43 per cent while those of super-Earths rose by 21 per cent.

Caltech planetary astronomer John Johnson said: 'We are showing that there is about one planet per star, and that gives us a total of about a hundred billion planets throughout our galaxy.

'The vast majority of those planets are orbiting stars that are very much different from our sun.'

Several of the planets being identified are in the same solar system, just as Earth is one of eight planets orbiting the Sun.

'The large number of multi-candidate systems being found by Kepler implies that a substantial fraction of exoplanets reside in flat multi-planet systems," said Jack Lissauer, planetary scientist at Ames.

'This is consistent with what we know about our own planetary neighborhood.'

The Kepler space telescope was launched by NASA in 2009 with the intention of finding Earth-like planets.

It pinpoints potential new planets by measuring the dimming of starlight as planets pass between stars and the telescope.

Not all dimming is caused by planets and it is only once dimming has been observed three times that it is formally attributed to a potential planet.

Further measurements and observations are required to confirm the identification.

In the last year the number of confirmed planets pinpointed by Kepler has risen from 33 to 105.

Newborn star: Herbig-Haro 110 is a geyser of hot gas from a newborn star that splashes up against and ricochets off the dense core of a cloud of molecular hydrogen

Far far away: Lying 45 million light-years away from Earth in the southern constellation of Fornax, a bright star-forming ring that surrounds the heart of the barred spiral galaxy

Cosmic dance: About 300 million light-years away, only four of these five galaxies are actually locked in a cosmic dance of repeated close encounters

Francois Fression of the Harvard-Smithsonian Center presented the latest Kepler findings at a meeting of the American Astronomical Society in Long Beach, California, on Monday.

The Astrophysical Journal has accepted a paper detailing the research for publication. 

Christopher Burke, a scientist at the SETI Institute which researches signs off extra-terrestrial intelligence, said that 58 planets found so far are believed to be in their host stars' habitable zones.

That means that any water on them has a chance of being in liquid form because the region is close enough to the star to be warm enough for ice to melt but not so close that it all evaporates.

Near death: A new photo of Eta Carinae system's largest star suffering a near-death experience before it goes supernova in the near future

Planets orbiting close to their suns are likely to be infernos while planets in distant orbits are likely to be icy, he said. Burke also analyzed the latest Kepler data.

The Kepler Space Telescope launched on March 7, 2009, and has been active for 3 years, 10 months and 1 day as of January 8, 2013.

The space observatory was named in honor of the 17th-century German astronomer Johannes Kepler.

Kepler is part of NASA's Discovery Program which runs relatively low-cost scientific research missions.

The observatory’s mission going forward is to find and document Earth-sized planets at greater distances. 

The more planets discovered with Earth-like orbits in their habitable zones, the greater the chances of extra-terrestrial life, scientists say. 

Sun-like star: Located just beyond the tip of the tail of the constellation of Cygnus, this butterfly-shaped cloud of glowing gas and dust is the wreckage of a star similar to the Sun

Distorted galaxies: Antennae Galaxies are a pair of distorted colliding spiral galaxies about 70 million light-years away, in the constellation of Corvus

Cosmic collision: The result of a cosmic collision where a smaller galaxy plunged right through the heart of a larger one and shot out the other side