Re: News: Evolution pace differentiates climate on Venus, Earth.

On Apr 7, 8:18 pm, Ernest Major <{$t...@xxxxxxxxxxxxxxxxx> wrote:
In message
<e0d0dfc4-b9e4-4553-8bab-fc2fa36f2...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Andre Lieven <andrelie...@xxxxxxxx> writes

On Apr 7, 6:32 pm, Ye Old One <use...@xxxxxxxxx> wrote:
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/3...

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.'

Frankly, none of this is new news to me, as various spacecraft that
have been flying by, orbiting, or landing on Venus have long ago
provided the info about Venus' atmosphere being mostly CO2,
as well as it's mean surface pressure being 90 Earth atmospheres.
Ditto on the surface heat.

The only thing about this, and I grant its not a small point, is the
connection of the loss of water to the non development of plate
tectonics on Venus.

That's not a new idea either - it may go back as far as the Magellan
mission, where the radar mapper failed to show evidence of plate
tectonics, but did show that Venus's surface had been reworked by
volcanic activity within the last few hundred million years.

Sure. My memory didn't quite resolve the issue of whether back then
the issue had been more or less settled on that point. I didn't want
to
point a finger that I wasn't sure about.

Andre

.

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