News: Evolution pace differentiates climate on Venus, Earth.

Evolution pace differentiates climate on Venus, earth
Malaysia Sun
Sunday 6th April, 2008
(IANS)
http://story.malaysiasun.com/index.php/ct/9/cid/b8de8e630faf3631/id/345573/cs/1/

Venus, considered earth's 'prodigal twin', has a climate that is
vastly different. And experts say it is because of the pace of
evolution on the two planets.

According to Fred Taylor of Oxford University, Venus evolved very
rapidly compared to the earth in the initial years - a crucial
difference.

The new information is being beamed to us from the European Venus
Express spacecraft now orbiting Venus.

Data from Venus Express suggests that the earth's twin once had
significant volume of water covering its surface, but these oceans
were lost in a very short geological timescale.

As a result, the geological evolution of the surface of Venus slowed
down because it was unable to develop plate tectonics like earth. And
biological evolution was prevented altogether.

Thus, in terms of Venus being another earth in climate and
habitability terms, it evolved too quickly at first, then too slowly.

'They may have started out looking very much the same, but
increasingly we have evidence that Venus lost most of its water and
Earth lost most of its atmospheric carbon dioxide,' said Taylor, who
presented these findings at the National Astronomy Meeting in Belfast
Friday.

On earth, CO2 is locked up in minerals in the crust, in the oceans,
and in plant life. The release of some of this back into the
atmosphere is the source of current concern about global warming and
climate change.

On Venus, most of the CO2 is still in the atmosphere and the surface
temperature is a scorching 450 degrees Celsius - much too hot for
life.

'The interesting thing is that the physics is the same in both cases,'
said Taylor.

'The great achievement of Venus Express is that it is putting the
climatic behaviour of both planets into a common framework of
understanding.'

--
Bob.

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