June 2, 2009 -- Researchers were stunned to discover recently that Earth is losing more of its atmosphere than Venus and Mars, which have negligible magnetic fields. This may mean our planet's magnetic shield may not be as solid a protective screen as once believed when it comes to guarding the atmosphere from an assault from the sun. "We often tell ourselves that we are very fortunate living on this planet because we have this strong magnetic shield that protects us from all sorts of things that the cosmos throws at us -- cosmic rays, solar flares and the pesky solar wind," said Christopher Russell, a professor of geophysics and space physics at the University of California, Los Angeles. "It certainly does help in some of those areas but ... in the case of the atmosphere, this may not be true," he said. Russel and others came to this realization while meeting at a comparative planetology conference last month. "Three of us who work on Earth, Venus and Mars got together and compared notes," Russell told Discovery News. "We said, 'Oh my goodness -- what we've been telling people about the magnetic shield is not correct.'" The perpetrators are streams of charged particles blasting off the sun in what is known as the solar wind. "The interaction of solar wind with Venus and Mars is pretty simple," Russell said. "The wind comes in, carries a magnetic field, which wraps around the ionosphere of the planet. The ionosphere is basically dragged away." Related Content:
Earth's magnetic field interacts with the solar wind, drawing out energy that gets funneled into the planet's atmosphere along its magnetic field lines. "The wind has to flow around this large magnetic obstacle in its path," Russell said. "The two are not friction-free." In addition to triggering aurorae, the process causes Earth's atmosphere to heat up to the point where atmospheric gases can escape along the field lines, where they are then picked up by the solar wind. "The visible manifestation of geomagnetic activity is the aurora -- the sun interacts with magnetosphere and causes it to glow -- but there are other things that go on when the particles interact with the atmosphere," said Scott Bailey, with the Center for Space Science and Engineering at Virginia Polytechnic Institute. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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See the Sun in Wide AngleSlide Show: Hottest Solar Images My Take: What's Wrong With Our Sun? Blog: STEREO Spying on Slumbering Sun HowStuffWorks: The Sun 
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