Discovery of Earth-like planet brings hope of finding alien life

A planet similar to Earth has been found orbiting a distant star by astronomers who believe they are getting closer to discovering an alien world inhabited by extraterrestrial life.

The new planet is five times the size of Earth but is itself unlikely to harbour life because it is probably covered in frozen oceans with average temperatures of around minus 220C.

However, the scientists behind the discovery believe the find marks a breakthrough in the search for relatively small, rocky planets such as Earth where temperatures are neither too hot nor too cold for life.

The scientists said that the discovery showed it was technically possible to discover a planet in a temperate "habitable zone" around a far-away sun that would permit the existence of liquid water, which is believed to be necessary for life.

The new planet, designated OGLE-2005-BLG-390Lb, is the smallest and the coldest planet yet discovered beyond the solar system. It orbits a star towards the centre of the Milky Way galaxy located 20,000 light years away in the constellation Sagittarius.

"This has huge implications for finding life," said Stephen Kane of the University of Florida, one of the 73 astronomers from the 32 institutions around the world involved in the study, published today in the journal Nature. "The good thing about this is it shows that planets this size might be quite common in habitable zones," Dr Kane said.

More than 150 planets are known to exist outside our solar system but the vast majority are large, gaseous planets, like Jupiter. The latest planet has an orbit three times the distance between the Earth and the Sun, meaning its temperatures are similar to those of permanently-frozen Pluto.

The discovery was made last summer using a technique called gravitational microlensing. Light from a bright, distant star is bent by the gravity of an intervening star to make the distant star appear larger than it is. This affect can be distorted when a planet is orbiting the intervening star.

Bohdan Paczynski at Princeton University said: "We may predict with reasonable probability that gravitational microlensing will discover planets with masses like that of Earth at a similar distance from their stars and with comparable surface temperatures."

A number of telescopes in the southern hemisphere - which has the best view of the "galactic bulge" of stars at the centre of the Milky Way - took part.

The robotically-controlled telescopes surveyed millions of stars in the hope that a second star with a nearby planet would intervene during the period of observation.

"With this method, we let the gravity of a dim, intervening star act as a giant natural telescope for us, magnifying a more distant star, which then temporarily looks brighter," said Andrew Williams of the Perth Observatory in Australia.

"A small 'defect' in the brightening reveals the existence of a planet around the lens star," Dr Williams said.

Professor Keith Horn of the University of St Andrews said gravitational microlensing was a good way of identifying smaller, rocky planets and has already discovered three exoplanets.

"Microlensing is the fastest way to find small cool planets, down to the mass of the Earth. Our first three planet discoveries indicate small cool planets are abundant," Professor Horne said.

"If we can deploy robotic telescopes at additional sites in the southern hemisphere, they could make the first detection of extra-solar Earths," he said.

Start your day with The Independent, sign up for daily news emails
Arts and Entertainment
musicOfficial chart could be moved to accommodate Friday international release day
Sport
Wes Brown is sent-off
football
News
i100
Sport
Italy celebrate scoring their second try
six nations
Sport
Glenn Murray celebrates scoring against West Ham
footballWest Ham 1 Crystal Palace 3
Arts and Entertainment
Drake continues to tease ahead of the release of his new album
music
ebooks
ebooksA special investigation by Andy McSmith
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Bookkeeper / Office Co-ordinator

£9 per hour: Recruitment Genius: This role is based within a small family run ...

Recruitment Genius: Designer - Print & Digital

£28000 - £32000 per annum: Recruitment Genius: This Design and marketing agenc...

Recruitment Genius: Quantity Surveyor

£46000 per annum: Recruitment Genius: This property investment firm are lookin...

Recruitment Genius: Telesales / Telemarketing Executive - OTE £30k / £35k plus

£18000 - £35000 per annum: Recruitment Genius: This company specialises provid...

Day In a Page

The Last Word: For the good of the game: why on earth don’t we leave Fifa?

Michael Calvin's Last Word

For the good of the game: why on earth don’t we leave Fifa?
HIV pill: Scientists hail discovery of 'game-changer' that cuts the risk of infection among gay men by 86%

Scientists hail daily pill that protects against HIV infection

Breakthrough in battle against global scourge – but will the NHS pay for it?
How we must adjust our lifestyles to nature: Welcome to the 'Anthropocene', the human epoch

Time to play God

Welcome to the 'Anthropocene', the human epoch where we may need to redefine nature itself
MacGyver returns, but with a difference: Handyman hero of classic 1980s TV series to be recast as a woman

MacGyver returns, but with a difference

Handyman hero of classic 1980s TV series to be recast as a woman
Tunnel renaissance: Why cities are hiding roads down in the ground

Tunnel renaissance

Why cities are hiding roads underground
'Backstreet Boys - Show 'Em What You're Made Of': An affectionate look at five middle-aged men

Boys to men

The Backstreet Boys might be middle-aged, married and have dodgy knees, but a heartfelt documentary reveals they’re not going gently into pop’s good night
Crufts 2015: Should foreign dogs be allowed to compete?

Crufts 2015

Should foreign dogs be allowed to compete?
10 best projectors

How to make your home cinema more cinematic: 10 best projectors

Want to recreate the big-screen experience in your sitting room? IndyBest sizes up gadgets to form your film-watching
Manchester City 1 Barcelona 2 player ratings: Luis Suarez? Lionel Messi? Joe Hart? Who was the star man?

Manchester City vs Barcelona player ratings

Luis Suarez? Lionel Messi? Joe Hart? Who was the star man at the Etihad?
Arsenal vs Monaco: Monaco - the making of Gunners' manager Arsene Wenger

Monaco: the making of Wenger

Jack Pitt-Brooke speaks to former players and learns the Frenchman’s man-management has always been one of his best skills
Cricket World Cup 2015: Chris Gayle - the West Indies' enigma lives up to his reputation

Chris Gayle: The West Indies' enigma

Some said the game's eternal rebel was washed up. As ever, he proved he writes the scripts by producing a blistering World Cup innings
In Ukraine a dark world of hybrid warfare and murky loyalties prevails

In Ukraine a dark world of hybrid warfare

This war in the shadows has been going on since the fall of Mr Yanukovych
'Birdman' and 'Bullets Over Broadway': Homage or plagiarism?

Homage or plagiarism?

'Birdman' shares much DNA with Woody Allen's 'Bullets Over Broadway'
Broadchurch ends as damp squib not even David Tennant can revive

A damp squib not even David Tennant can revive

Broadchurch, Series 2 finale, review
A Koi carp breeding pond, wall-mounted iPads and a bathroom with a 'wellness' shower: inside the mansion of Germany's 'Bishop of Bling'

Inside the mansion of Germany's 'Bishop of Bling'

A Koi carp breeding pond, wall-mounted iPads and a bathroom with a 'wellness' shower