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17 April 2014 12:48 pm ,
Vol. 344 ,
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: The Mystery of the Absent Sunspots
2 March 2011 3:00 pm
The sun is usually a predictable beast, at least as far as its sunspot cycle goes. Every 11 years or so, the sun's magnetic activity peaks and then troughs, resulting in relatively high and then low numbers of dark spots and flares on the solar surface. But in the cycle that has just finished, the trough went on for much longer than normal, with more than twice as many days without sunspots compared with previous cycles. To figure out what caused this, researchers used a computer simulation of the churning hot plasma inside the sun. As each cycle progresses, the movement of this plasma (black loop) shifts the solar magnetic fields (gold strands)—from which sunspots erupt—from the sun's midlatitudes to its equator. An extended minimum occurs whenever the plasma moves quickly at the beginning of a cycle—preventing a large buildup of magnetic fields—but then slows down toward the end, delaying the onset of the next cycle, the team reports online today in Nature. This knowledge won't help in predicting individual solar storms, the researchers say, but it should give scientists a better idea of how stormy the sun will be in the years to come. And that should help to limit the worst effects of storms, be it damage to satellites in orbit or harm to people flying close to the poles.
See more ScienceShots.