Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new theory of climate change

27.02.2007
The leader of Sun-climate research at the Danish National Space Center, Henrik Svensmark, puts together the findings reported by him and his colleagues in a dozen scientific papers, to tell how the climate is governed by atomic particles coming from exploded stars.

These cosmic rays help to make ordinary clouds. High levels of cosmic rays and cloudiness cool the world, while milder intervals occur when cosmic rays and cloud cover diminish.


Cosmic radiation entering Earth's atmosphere. Credit: Danish National Space Center

The review paper entitled ‘Cosmoclimatology: a new theory emerges’ appears in the February issue of Astronomy & Geophysics. Here are some of its salient points.

For more than 20 years, satellite records of low-altitude clouds have closely followed variations in cosmic rays. Just how cosmic rays take part in cloud-making appeared in the SKY experiment, conducted in the basement of the Danish National Space Center. Electrons set free in the air by passing cosmic rays help to assemble the building blocks for cloud condensation nuclei on which water vapour condenses to make clouds.

Cosmic ray intensities – and therefore cloudiness – keep changing because the Sun’s magnetic field varies in its ability to repel cosmic rays coming from the Galaxy, before they can reach the Earth. Radioactive carbon-14 and other unusual atoms made in the atmosphere by cosmic rays provide a record of how cosmic-ray intensities have varied in the past. They explain repeated alternations between cold and warm periods during the past 12,000 years. Whenever the Sun was feeble and cosmic-ray intensities were high, cold conditions ensued, most recently in the Little Ace Age that climaxed 300 years ago.

On long timescales the intensity of cosmic rays varies more emphatically because the influx from the Galaxy changes. During the past 500 million years the Earth has passed through four ‘hothouse’ episodes, free of ice and with high sea levels, and four ‘icehouse’ episodes like the one we live in now, with ice-sheets, glaciers and relatively low sea levels.

Nir Shaviv of the Hebrew University in Jerusalem, together with Ján Veizer of the Ruhr University and the University of Ottawa, links these changes to the journey of the Sun and the Earth through the Milky Way Galaxy. They blame the icehouse episodes on encounters with bright spiral arms, where cosmic rays are most intense. More frequent chilling events, every 34 million years or so, occur whenever the solar system passes through with the mid-plane of the Galaxy.

In Snowball Earth episodes around 700 and 2300 million years ago, even the Equator was icy. At those times the birth-rate of stars in the Galaxy was unusually high, which would have also meant a large number of exploding stars and intense cosmic rays. Earlier still, the theory of cosmic rays and clouds helps to explain why the Earth did not freeze solid when it was very young. The Sun was much fainter than it is now, but also more vigorous in repelling cosmic rays, so the Earth would not have had much cloud cover.

While calculating the changing influx since life began about 3.8 billion years ago, Dr Svensmark discovered a surprising connection between cosmic-ray intensities and a variability of the productivity of life. The biggest fluctuations in productivity coincided with high star formation rates and cool periods in the Earth’s climate. Conversely, during a billion years when star formation was slow, cosmic rays were less intense and the Earth’s climate was warmer, the biosphere was almost unchanging in its productivity.

Near the end of his review Dr Svensmark writes: ‘The past 10 years have seen the reconnaissance of a new area of research by a small number of investigators. The multidisciplinary nature of cosmoclimatology is both a challenge and an opportunity for many lines of inquiry.’ Even the search for alien life is affected, because it should now take into account of the need for the right magnetic environment, if life is to originate and survive on the planets of other stars.

Sune Nordentoft Lauritsen | alfa
Further information:
http://www.spacecenter.dk
http://www.spacecenter.dk/research/sun-climate/a-new-theory-of-climate-change

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>