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Climate catastrophes in the Solar System (Forwarded)



 
 
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  #1  
Old April 26th 07, 06:11 PM posted to sci.astro
Andrew Yee
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Posts: 667
Default Climate catastrophes in the Solar System (Forwarded)

ESA News
http://www.esa.int

26 April 2007

Climate catastrophes in the Solar System

Earth sits between two worlds that have been devastated by climate
catastrophes. In the effort to combat global warming, our neighbours can
provide valuable insights into the way climate catastrophes affect
planets.

Modelling Earth's climate to predict its future has assumed tremendous
importance in the light of mankind's influence on the atmosphere. The
climate of our two neighbours is in stark contrast to that of our home
planet, making data from ESA's Venus Express and Mars Express invaluable
to climate scientists.

Venus is a cloudy inferno whilst Mars is a frigid desert. As current
concerns about global warming have now achieved widespread acceptance,
pressure has increased on scientists to propose solutions.

The key weapon in a climate scientist's arsenal is the climate model, a
computer programme that uses the equations of physics to investigate the
way in which Earth's atmosphere works. The programme helps predict how the
atmosphere might change in the future.

"To members of the public it must seem like climate models are crystal
balls, but they are actually just complex equations," says David
Grinspoon, Denver Museum of Nature and Science, and one of Venus Express's
interdisciplinary scientists.

The more scientists look at those equations, the more they realise just
how complicated Earth's climate system is. Grinspoon puts the predicament
like this: "In fifty or a hundred years, we will know whether today's
climate models were right but if they are wrong, by then it will be too
late."

To help increase confidence in the computer models, Grinspoon believes
that scientists should look at our neighbouring planets. "It seems that
both Mars and Venus started out much more like Earth and then changed.
They both hold priceless climate information for Earth," says Grinspoon.

The atmosphere of Venus is much thicker than Earth's. Nevertheless,
current climate models can reproduce its present temperature structure
well. Now planetary scientists want to turn the clock back to understand
why and how Venus changed from its former Earth-like conditions into the
inferno of today.

They believe that the planet experienced a runaway greenhouse effect as
the Sun gradually heated up. Astronomers believe that the young Sun was
dimmer than the present-day Sun by 30 percent. Over the last 4 thousand
million years, it has gradually brightened. During this increase, Venus's
surface water evaporated and entered the atmosphere.

"Water vapour is a powerful greenhouse gas and it caused the planet to
heat-up even more. This is turn caused more water to evaporate and led to
a powerful positive feedback response known as the runaway greenhouse
effect," says Grinspoon.

As Earth warms in response to manmade pollution, it risks the same fate.
Reconstructing the climate of the past on Venus can give scientists a
better understanding of how close our planet is to such a catastrophe.
However, determining when Venus passed the point of no return is not easy.
That's where ESA's Venus Express comes in.

The spacecraft is in orbit around Venus collecting data that will help
unlock the planet's past. Venus is losing gas from its atmosphere, so
Venus Express is measuring the rate of this loss and the composition of
the gas being lost. It also watches the movement of clouds in the planet's
atmosphere. This reveals the way Venus responds to the absorption of
sunlight, because the energy from the Sun provides the power that allows
the atmosphere to move.

In addition, Venus Express is charting the amount and location of sulphur
dioxide in the planet's atmosphere. Sulphur dioxide is a greenhouse gas
and is released by volcanoes on Venus.

"Understanding all of this will help us pin down when Venus lost its
water," says Grinspoon. That knowledge can feed into the interpretation of
climate models on the Earth because although both planets seem very
different now, the same laws of physics govern both worlds.

Understanding Mars' past is equally important. ESA's Mars Express is
currently investigating the fate of the Red Planet. Smaller than the
Earth, Mars is thought to have lost its atmosphere to space. When Martian
volcanoes became extinct, so did the planet's means of replenishing its
atmosphere turning it into an almost-airless desert.

"What happened on these two worlds is very different but either would be
equally disastrous for Earth. We are banking on our ability to accurately
predict Earth's future climate," says Grinspoon. Anything that can shed
light on our own future is valuable. That is why the study of our
neighbouring worlds is vital.

So, when planetary scientists talk of exploring other worlds, they are
also increasing their ability to understand our own planet.

For more information:

David Grinspoon
Venus Express interdisciplinary Scientist and Curator of Astrobiology
Dept. of Space Sciences
Denver Museum of Nature & Science, Co. (USA)
Email: David.Grinspoon @ dmns.org

Håkan Svedhem, ESA Venus Express Project scientist
Email: Håkan.svedhem @ esa.int

[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaCP/SEM2EHMJC0F_index_1.html ]


  #2  
Old April 26th 07, 06:25 PM posted to sci.astro
Jan Panteltje
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Posts: 453
Default Climate catastrophes in the Solar System (Forwarded)

On a sunny day (Thu, 26 Apr 2007 17:11:10 GMT) it happened Andrew Yee
wrote in
:

to climate scientists.

Venus is a cloudy inferno whilst Mars is a frigid desert.
As current
concerns about global warming have now achieved widespread acceptance,
pressure has increased on scientists to propose solutions.


Yes, listen to the masses, real science, NOT see joke below:

They believe that the planet experienced a runaway greenhouse effect as
the Sun gradually heated up. Astronomers believe that the young Sun was
dimmer than the present-day Sun by 30 percent. Over the last 4 thousand
million years, it has gradually brightened. During this increase, Venus's
surface water evaporated and entered the atmosphere.


OK, so they say this (line one joke).

As Earth warms in response to manmade pollution, it risks the same fate.


Second and last line joke.

Now should I laugh or should I cry, or just go sit in the sun?

WHOOOOOOAAAAAAAAAAAAAAAAAAAAAAAAAA

Nothing like 1000% contradicting them selves for the greenopmaniacs.

LOL


 




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