Getting closer to the cosmic connection to climate
http://www.innovations-report.de/html/berichte/physik_astronomie/bericht-=

^ | 04.10.2006 | n=E4chste Meldung

An essential role for remote stars in everyday weather on Earth has
been revealed by an experiment at the Danish National Space Center in
Copenhagen. It is already well-established that when cosmic rays,
which are high-speed atomic particles originating in exploded stars
far away in the Milky Way, penetrate Earth's atmosphere they produce
substantial amounts of ions and release free electrons. Now, results
from the Danish experiment show that the released electrons
significantly promote the formation of building blocks for cloud
condensation nuclei on which water vapour condenses to make clouds.

Hence, a causal mechanism by which cosmic rays can facilitate the
production of clouds in Earth's atmosphere has been experimentally
identified for the first time.

The Danish team officially announce their discovery on Wednesday in
Proceedings of the Royal Society A, published by the Royal Society,
the British national academy of science.

The experiment

The experiment called SKY (Danish for 'cloud') took place in a large
reaction chamber which contained a mixture of gases at realistic
concentrations to imitate the chemistry of the lower atmosphere.
Ultraviolet lamps mimicked the action of the Sun's rays. During
experimental runs, instruments traced the chemical action of the
penetrating cosmic rays in the reaction chamber.

The data revealed that electrons released by cosmic rays act as
catalysts, which significantly accelerate the formation of stable,
ultra-small clusters of sulphuric acid and water molecules which are
building blocks for the cloud condensation nuclei. A vast numbers of
such microscopic droplets appeared, floating in the air in the
reaction chamber.

'We were amazed by the speed and efficiency with which the electrons
do their work of creating the building blocks for the cloud
condensation nuclei,' says team leader Henrik Svensmark, who is
Director of the Center for Sun-Climate Research within the Danish
National Space Center. 'This is a completely new result within climate
science.'

A missing link in climate theory

The experimental results lend strong empirical support to the theory
proposed a decade ago by Henrik Svensmark and Eigil Friis-Christensen
that cosmic rays influence Earth's climate through their effect on
cloud formation. The original theory rested on data showing a strong
correlation between variation in the intensity of cosmic radiation
penetrating the atmosphere and the amount of low-altitude clouds.
Cloud cover increases when the intensity of cosmic rays grows and
decreases when the intensity declines.

It is known that low-altitude clouds have an overall cooling effect on
the Earth's surface. Hence, variations in cloud cover caused by cosmic
rays can change the surface temperature. The existence of such a
cosmic connection to Earth's climate might thus help to explain past
and present variations in Earth's climate.

Interestingly, during the 20th Century, the Sun's magnetic field which
shields Earth from cosmic rays more than doubled, thereby reducing the
average influx of cosmic rays. The resulting reduction in cloudiness,
especially of low-altitude clouds, may be a significant factor in the
global warming Earth has undergone during the last century. However,
until now, there has been no experimental evidence of how the causal
mechanism linking cosmic rays and cloud formation may work.

'Many climate scientists have considered the linkages from cosmic rays
to clouds to climate as unproven,' comments Eigil Friis-Christensen,
who is now Director of the Danish National Space Center. 'Some said
there was no conceivable way in which cosmic rays could influence
cloud cover. The SKY experiment now shows how they do so, and should
help to put the cosmic-ray connection firmly onto the agenda of
international climate research.'

--
Wherever I go it will be well with me, for it was well with me here, not
on account of the place, but of my judgments which I shall carry away
with me, for no one can deprive me of these; on the contrary, they alone
are my property, and cannot be taken away, and to possess them suffices
me wherever I am or whatever I do. -- EPICTETUS

"There are no absolute certainties in this universe. A man must try to
whip order into a yelping pack of probabilities, and uniform success is
impossible." -- Jack Vance

"Civilization is the interval between Ice Ages." -- Will Durant.


"Progress is the increasing control of the environment by life.
--Will Durant
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Joseph R. Darancette
daranc@NOSPAMverizon.net