How Nearby Supernovae Affected Life On Earth 109
sycodon writes with news of research into how nearby supernovae affected the development of life on Earth. "[Professor Henrik Svensmark] found that the changing frequency of nearby supernovae seems to have strongly shaped the conditions for life on Earth. Whenever the Sun and its planets have visited regions of enhanced star formation in the Milky Way Galaxy, where exploding stars are most common, life has prospered. Prof. Svensmark remarks in the paper, "The biosphere seems to contain a reflection of the sky, in that the evolution of life mirrors the evolution of the Galaxy.' ... The data also support the idea of a long-term link between cosmic rays and climate, with these climatic changes underlying the biological effects. And compared with the temperature variations seen on short timescales as a consequence of the Sun's influence on the influx of cosmic rays, the heating and cooling of the Earth due to cosmic rays varying with the prevailing supernova rate have been far larger.""
Re:How does a supernova cool the atmosphere? (Score:5, Informative)
Re:How does a supernova cool the atmosphere? (Score:5, Informative)
Cosmic rays are charged particles that bombard the Earth's atmosphere from outer space. Studies suggest they may have an influence on the amount of cloud cover through the formation of new aerosols (tiny particles suspended in the air that seed cloud droplets). This is supported by satellite measurements, which show a possible correlation between cosmic-ray intensity and the amount of low cloud cover. Clouds exert a strong influence on the Earth’s energy balance; changes of only a few per cent have an important effect on the climate.
http://public.web.cern.ch/public/en/research/CLOUD-en.html [web.cern.ch]
Re:Trying to parse... (Score:5, Informative)
Classic politically motivated Slashdot climate post.
The guy didn't say anything about current warming, carbon dioxide, human activities or anything else. He's saying that cosmic rays influence climate (they do), short term variation due to the sun's magnetic field have a fairly small effect (the opposite of the words you're trying to put in his mouth) and a bunch of supernovae going off nearby has a larger effect (not hard to believe).
Well, duh! Is anyone on Slashdot surprised? (Score:4, Informative)
Svensmark is the scientist whose controversial ideas ultimately led CERN to conduct its CLOUD experiment. The gist of his idea was: cosmic particle presence (more clouds, due to more substrate) and solar magnetic activity (less clouds, due to repelled particles) are amongst the driving factors --perhaps the primary one-- of climate volatility on Earth, because they control overall cloud cover.
CERN's conclusion? Svensmark was basically spot on with respect to cloud formation.
Make no mistake here. Clouds excersice materially high positive and negative feedback loops on climate. Whether it is overwhelmingly superior or merely predominant to carbon dioxide et al is the only point of contention.
In light of this, is any Slashdot reader surprised that proximity of supernovae, aka amount of cosmic particles, accepting the evidence that the latter have an impact on cloud cover and thus on climate, might have an impact on how life in thriving on Earth?
Re:Star Trek (Score:4, Informative)
I found it a really strong episode, not for the plot (Which, like most trek, is BS) but for the way Q and Picard play off each other. TNG's best episodes often have a strong Q/Picard dynamic. My favourite being Tapestry, which had that *and* a half decent story around it.
Disclaimer: I am not a trekkie. Despite looking like your stereotypical example of one
Re:How does a supernova cool the atmosphere? (Score:4, Informative)
Except that the person above you posted a link to the CERN site for CLOUD which includes a link to CLOUD's website (http://cloud.web.cern.ch/cloud/) which includes a link to their publications (http://cloud.web.cern.ch/cloud/People/Publications.html). All they have is some preliminary data from a prototype but still includes a link to the initial publication "Results from the CERN pilot CLOUD experiment" (http://www.atmos-chem-phys.net/10/1635/2010/acp-10-1635-2010.html)
But that probably doesn't fit with what ever decoder ring you found at the bottom of your box of cocoa pebbles which rather than suggesting you drink more Ovaltine apparently claimed that CLOUD results are classified.