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
ebooks
ebooksA celebration of British elections
  • Get to the point
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: Senior Digital Marketing Consultant

£28000 - £45000 per annum: Recruitment Genius: A Senior Digital Marketing Cons...

Recruitment Genius: Assistant Stores Keeper

£16640 - £18500 per annum: Recruitment Genius: An Assistant Stores Keeper is r...

Recruitment Genius: Claims Administrator

£16000 - £18500 per annum: Recruitment Genius: This is an excellent opportunit...

Recruitment Genius: Software Developer - C# / ASP.NET / SQL

£17000 - £30000 per annum: Recruitment Genius: Developer required to join a bu...

Day In a Page

'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power
Rare and exclusive video shows the horrific price paid by activists for challenging the rule of jihadist extremists in Syria

The price to be paid for challenging the rule of extremists

A revolution now 'consuming its own children'
Welcome to the world of Megagames

Welcome to the world of Megagames

300 players take part in Watch the Skies! board game in London
'Nymphomaniac' actress reveals what it was really like to star in one of the most explicit films ever

Charlotte Gainsbourg on 'Nymphomaniac'

Starring in one of the most explicit films ever
Robert Fisk in Abu Dhabi: The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers

Robert Fisk in Abu Dhabi

The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers
Vince Cable interview: Charging fees for employment tribunals was 'a very bad move'

Vince Cable exclusive interview

Charging fees for employment tribunals was 'a very bad move'
Iwan Rheon interview: Game of Thrones star returns to his Welsh roots to record debut album

Iwan Rheon is returning to his Welsh roots

Rheon is best known for his role as the Bastard of Bolton. It's gruelling playing a sadistic torturer, he tells Craig McLean, but it hasn't stopped him recording an album of Welsh psychedelia
Russell Brand's interview with Ed Miliband has got everyone talking about The Trews

Everyone is talking about The Trews

Russell Brand's 'true news' videos attract millions of viewers. But today's 'Milibrand' interview introduced his resolutely amateurish style to a whole new crowd
Morne Hardenberg interview: Cameraman for BBC's upcoming show Shark on filming the ocean's most dangerous predator

It's time for my close-up

Meet the man who films great whites for a living
Increasing numbers of homeless people in America keep their mobile phones on the streets

Homeless people keep mobile phones

A homeless person with a smartphone is a common sight in the US. And that's creating a network where the 'hobo' community can share information - and fight stigma - like never before
'Queer saint' Peter Watson left his mark on British culture by bankrolling artworld giants

'Queer saint' who bankrolled artworld giants

British culture owes a huge debt to Peter Watson, says Michael Prodger
Pushkin Prizes: Unusual exchange programme aims to bring countries together through culture

Pushkin Prizes brings countries together

Ten Scottish schoolchildren and their Russian peers attended a creative writing workshop in the Highlands this week
14 best kids' hoodies

14 best kids' hoodies

Don't get caught out by that wind on the beach. Zip them up in a lightweight top to see them through summer to autumn
Robert Fisk in Abu Dhabi: The acceptable face of the Emirates

The acceptable face of the Emirates

Has Abu Dhabi found a way to blend petrodollars with principles, asks Robert Fisk