Article Posted on : - Jun 24, 2010

An artist's conception of the Venus Express. An ESA Photo

PARIS (BNS): Planetary scientists from across the world will congregate in Aussois, France this week to deliberate on whether the planet Venus ever had oceans in the early stages of its evolution.

European Space Agency’s Venus Express orbiter, after surveying the planet, has found several similarities between the Earth and Venus.

Even though the planet has a very high temperature, “the basic composition of Venus and Earth is very similar,” says Håkan Svedhem, ESA Venus Express Project Scientist. The planet has very little water content today as compared to Earth, but according to scientists, billions of years ago, Venus probably had much more water.

The Venus Express has certainly confirmed that the planet has lost a large quantity of water into space, ESA said.

The reason cited for the loss of water in Venus is due to the penetration of Sun's ultraviolet rays into the planet's atmosphere which break up the water molecules into hydrogen and oxygen atoms which then escape to space.

The ESA orbiter has measured the rate of this escape and confirmed that roughly twice as much hydrogen is escaping as oxygen. It is therefore believed that water is the source of these escaping ions.

The spacecraft has also shown that a heavy form of hydrogen, called deuterium, is progressively enriched in the upper echelons of Venus’s atmosphere, because the heavier hydrogen will find it less easy to escape the planet’s grip.

“Everything points to there being large amounts of water on Venus in the past,” says to Colin Wilson, Oxford University, UK. But that does not necessarily mean there were oceans on the planet’s surface.

Another scientist, Eric Chassefière, also believes that there was no ocean in the planet as water in Venus was largely atmospheric and existed only during the very earliest times, when Venus's surface was completely molten.

The data provided by Venus Express spacecraft is expected to be valuable in finding a validating answer to this puzzle.