Two more planets are found beyond the solar system

Astronomers have reached another milestone in their search for life on other worlds with the discovery of two more planets around distant stars.

The planets may be smaller than Saturn - the second largest planet in the solar system - and their discovery marks the first time objects smaller than Jupiter, the biggest-known planet, have been detected.

Of the 30 extra-solar planets discovered over the past eight years, all have been about the size of Jupiter, a gas giant that cannot support life.

Detection of smaller planets demonstrates it may soon be possible to find Earth-sized planets some 300 times smaller than Jupiter that might be capable of supporting life.

Using the giant Keck telescope on Mauna Kea in Hawaii, the astronomers were able to find the planets from the gravitational wobble they caused as they disturbed the stars around which they orbit. The discovery was made by a team of three planet sleuths, Geoff Marcy of the University of California, Berkeley, Paul Butler of the Carnegie Institution of Washington and Steve Voigt of the University of California, Santa Cruz.

The existence of planets the size of Saturn, which is three times smaller than Jupiter, confirms a 20-year-old theory of how planets form by a snowball effect, growing as a proto-planet collects debris from a star-encircling disk of dust.

Dr Macy said that searching for smaller planets is like looking at a beach from a distance. "Previously we only saw the large boulders, which were Jupiter-sized planets or larger. Now we are seeing the rocks, Saturn-sized planets or smaller," he said. "We still don't have the capability of detecting Earth-like planets, which would be equivalent to seeing pebbles on the beach."

One of the planets is at least 80 per cent of the mass of Saturn and orbits at a distance of 3.8 million miles from the star HD46375, which lies 109 light years away in the constellation Monoceros. The other is slightly smaller and orbits at 32.5 million miles from the star 79 Ceti, which is 117 light-years away in the constellation Cetus.

Both planets have short orbits, taking just 3 days and 75 days to make a full circle around their respective stars.

America hopes to launch a planet-hunting space telescope in 2006 to photograph planets up to five times bigger than Earth at 50 light-years.

Start your day with The Independent, sign up for daily news emails
PROMOTED VIDEO
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

Tradewind Recruitment: KS2 Teacher

Negotiable: Tradewind Recruitment: My client is a two form entry primary schoo...

Tradewind Recruitment: English Teacher

Negotiable: Tradewind Recruitment: My client is an excellent, large partially ...

Tradewind Recruitment: Science Teacher

£90 - £140 per day: Tradewind Recruitment: I am currently working in partnersh...

Tradewind Recruitment: Year 3 Primary Teacher

£100 - £150 per day: Tradewind Recruitment: Year 3 Teacher Birmingham Jan 2015...

Day In a Page

Isis hostage crisis: The prisoner swap has only one purpose for the militants - recognition its Islamic State exists and that foreign nations acknowledge its power

Isis hostage crisis

The prisoner swap has only one purpose for the militants - recognition its Islamic State exists and that foreign nations acknowledge its power, says Robert Fisk
Missing salvage expert who found $50m of sunken treasure before disappearing, tracked down at last

The runaway buccaneers and the ship full of gold

Salvage expert Tommy Thompson found sunken treasure worth millions. Then he vanished... until now
Homeless Veterans appeal: ‘If you’re hard on the world you are hard on yourself’

Homeless Veterans appeal: ‘If you’re hard on the world you are hard on yourself’

Maverick artist Grayson Perry backs our campaign
Assisted Dying Bill: I want to be able to decide about my own death - I want to have control of my life

Assisted Dying Bill: 'I want control of my life'

This week the Assisted Dying Bill is debated in the Lords. Virginia Ironside, who has already made plans for her own self-deliverance, argues that it's time we allowed people a humane, compassionate death
Move over, kale - cabbage is the new rising star

Cabbage is king again

Sophie Morris banishes thoughts of soggy school dinners and turns over a new leaf
11 best winter skin treats

Give your moisturiser a helping hand: 11 best winter skin treats

Get an extra boost of nourishment from one of these hard-working products
Paul Scholes column: The more Jose Mourinho attempts to influence match officials, the more they are likely to ignore him

Paul Scholes column

The more Jose Mourinho attempts to influence match officials, the more they are likely to ignore him
Frank Warren column: No cigar, but pots of money: here come the Cubans

Frank Warren's Ringside

No cigar, but pots of money: here come the Cubans
Isis hostage crisis: Militant group stands strong as its numerous enemies fail to find a common plan to defeat it

Isis stands strong as its numerous enemies fail to find a common plan to defeat it

The jihadis are being squeezed militarily and economically, but there is no sign of an implosion, says Patrick Cockburn
Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action

Virtual reality: Seeing is believing

Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action
Homeless Veterans appeal: MP says Coalition ‘not doing enough’

Homeless Veterans appeal

MP says Coalition ‘not doing enough’ to help
Larry David, Steve Coogan and other comedians share stories of depression in new documentary

Comedians share stories of depression

The director of the new documentary, Kevin Pollak, tells Jessica Barrett how he got them to talk
Has The Archers lost the plot with it's spicy storylines?

Has The Archers lost the plot?

A growing number of listeners are voicing their discontent over the rural soap's spicy storylines; so loudly that even the BBC's director-general seems worried, says Simon Kelner
English Heritage adds 14 post-war office buildings to its protected lists

14 office buildings added to protected lists

Christopher Beanland explores the underrated appeal of these palaces of pen-pushing
Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

Scientists unearthed the cranial fragments from Manot Cave in West Galilee