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17 April 2014 12:48 pm ,
Vol. 344 ,
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
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...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Solar Wind Stifles Mercury's Magnetic Field
22 December 2011 2:00 pm
Ever since NASA's Mariner 10 spacecraft zipped past Mercury in 1974, scientists have wondered why the planet's magnetic field is so much wimpier than expected. Now, a new study led by researchers at Braunschweig University of Technology in Germany suggests that the solar wind—the incessant flow of charged particles boiling off the sun's surface—suppresses the field generated by the flow of molten iron in the planet's outer core. On the sunward side of Mercury, the magnetopause—the protective shield created by the planet's magnetic field—sits just 1200 kilometers above the planet's surface. That's so close, the team's computer models indicate, that magnetic fields created by particles flowing along the magnetopause reach deep into Mercury itself, counteracting the internally-generated field. Without the external fields generated by the solar wind, Mercury's magnetic field might be about 30 times stronger than it actually is, the researchers report today in Science. NASA's MESSENGER probe (artist's concept above) has been orbiting Mercury since mid-March and will provide unprecedented measurements of the strength and direction of the planet's magnetic field, revealing more about how such fields are generated in the first place.
See more ScienceShots.