Why the Earth's twin became a wasteland

It is a world stripped of water and scarred by searing temperatures hot enough to melt lead. Yet Venus may once have been a planet much like Earth, where vast oceans of water could have supported life.

The first detailed analysis of data gathered by a European space probe has revealed tantalising evidence that Venus often considered Earth's twin planet became so inhospitable for life because of a series of chance events.

Scientists have confirmed that the similarities between Venus and Earth were overshadowed by a shift in the former's history that led to the loss of the Venusian oceans, an atmosphere clogged with carbon dioxide and a runaway greenhouse effect that gave rise to severe global warming.

The Venus Express, launched two years ago and orbiting the planet for a year taking measurements, has helped to shed light on why the climate of Earth's twin is so severe, said Professor Fred Taylor, of Oxford University. "It is now becoming clear why the climate on Venus is so different from Earth, when the planets themselves are otherwise quite similar," he said.

Venus is the closest planet to Earth in terms of its distance from the Sun, its mass, radius, density and chemical composition. Venus differs in terms of its slow rate of rotation once every 243 Earth days and yet it is hard to imagine the two climates being more different.

"These differences are not just down to Venus being closer to the Sun," Professor Taylor said. "We now know that the lack of a protective magnetic field and the differing planetary rotation rates also play a role in ensuring many of the atmospheric processes we observe on Earth occur at a much faster rate on Venus.

"Our new data make it possible to construct a scenario in which Venus started out like the Earth, possibly including a habitable environment, billions of years ago, and evolved to the state we see now."

Venus Express has confirmed that the lack of a magnetic field made Venus vulnerable to the water-stripping properties of the solar wind, a high-speed stream of charged particles that split water molecules in two and allow the vital hydrogen in water to escape into space.

The oceans on Earth have been critical in trapping carbon dioxide as carbonate rocks; on Venus, the carbon dioxide has been released into its atmosphere to cause a runaway greenhouse effect, with surface temperatures averaging about 450C.

The latest results from Venus Express, in the journal Nature, show the atmosphere is a turbulent, three-dimensional structure which can be divided into four major components from the Venusian equator to the poles, Professor Taylor said. They also reveal that Venus experiences lightning strikes, and that they may even be more common than on Earth, which has important implications for the chemistry of the planet's atmosphere.

More than 30 spacecraft have visited Venus since the first probe, Mariner 2, was sent by the United States in 1962. Venus Express is loaded with scientific instruments designed to monitor a suite of phenomena, such as the amount of heavy water vapour in the atmosphere and the strength of any magnetic field. One of the biggest mysteries is how Venus lost its water, although the lack of a protective magnetic field suggests it was something to do with the solar wind.

Andrew Ingersoll, of the California Institute of Technology in Pasadena, said: "Because Venus is close to Earth in so many ways, it seems likely that the two planets started out similarly. Venus must once have had an ocean's worth of water, but lost it somehow. The escape mechanism probably involves the solar wind the stream of charged particles emanating from the Sun which strips atoms and ions out of the atmosphere. But the details are contradictory."

Venus by the numbers

457C surface temperature 96% of atmosphere made up of carbon dioxide, leading to surface pressure 92 times greater than that of Earth. The sun rises and sets every 117 earth days and the planet spins once relative to the stars every 243 days. As night falls, the temperature can drop by up to 240C. At cloud-level, wind speeds reach 360 kph three times hurricane force. At its poles, instead of cold cores, Venus has cold collars, inside of which air temperature rises by 263C.

Start your day with The Independent, sign up for daily news emails
Danny Cipriani of England breaks clear to score his second try
Life and Style
New research says leaving your desk can help you to avoid serious illness
Arts and Entertainment
tvSPOILER ALERT: Like a mash-up of 28 Days Later, Braveheart, The Killing and Lord of the Rings, this GoT episode was a belter
ebooksAn unforgettable anthology of contemporary reportage
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

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

iJobs Job Widget
iJobs General

Recruitment Genius: Graduate Trainee

£15000 - £20000 per annum: Recruitment Genius: This Cloud ERP Solution Provide...

Recruitment Genius: Business Development Executive / Digital Marketing Executive

£26000 - £35000 per annum: Recruitment Genius: A luxury beauty house with a nu...

Recruitment Genius: Housekeepers - Immediate Start

£8 per hour: Recruitment Genius: This company are currently recruiting new exp...

Recruitment Genius: Head Concierge

£25000 - £28000 per annum: Recruitment Genius: This award winning Property Man...

Day In a Page

On your feet! Spending at least two hours a day standing reduces the risk of heart attacks, cancer and diabetes, according to new research

On your feet!

Spending half the day standing 'reduces risk of heart attacks and cancer'
Liverpool close in on Milner signing

Liverpool close in on Milner signing

Reds baulk at Christian Benteke £32.5m release clause
With scores of surgeries closing, what hope is there for the David Cameron's promise of 5,000 more GPs and a 24/7 NHS?

The big NHS question

Why are there so few new GPs when so many want to study medicine?
Big knickers are back: Thongs ain't what they used to be

Thongs ain't what they used to be

Big knickers are back
Thurston Moore interview

Thurston Moore interview

On living in London, Sonic Youth and musical memoirs
In full bloom

In full bloom

Floral print womenswear
From leading man to Elephant Man, Bradley Cooper is terrific

From leading man to Elephant Man

Bradley Cooper is terrific
In this the person to restore our trust in the banks?

In this the person to restore our trust in the banks?

Dame Colette Bowe - interview
When do the creative juices dry up?

When do the creative juices dry up?

David Lodge thinks he knows
The 'Cher moment' happening across fashion just now

Fashion's Cher moment

Ageing beauty will always be more classy than all that booty
Thousands of teenage girls enduring debilitating illnesses after routine school cancer vaccination

Health fears over school cancer jab

Shock new Freedom of Information figures show how thousands of girls have suffered serious symptoms after routine HPV injection
Fifa President Sepp Blatter warns his opponents: 'I forgive everyone, but I don't forget'

'I forgive everyone, but I don't forget'

Fifa president Sepp Blatter issues defiant warning to opponents
Extreme summer temperatures will soon cause deaths of up to 1,700 more Britons a year, says government report

Weather warning

Extreme summer temperatures will soon cause deaths of up to 1,700 more Britons a year, says government report
LSD: Speaking to volunteer users of the drug as trials get underway to see if it cures depression and addiction

High hopes for LSD

Meet the volunteer users helping to see if it cures depression and addiction
German soldier who died fighting for UK in Battle of Waterloo should be removed from museum display and given dignified funeral, say historians

Saving Private Brandt

A Belgian museum's display of the skeleton of a soldier killed at Waterloo prompts calls for him to be given a dignified funeral