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17 April 2014 12:48 pm ,
Vol. 344 ,
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,...
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...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Earth's Friendly Fire
10 May 2002 (All day)
When a space storm whips up, Earth becomes enveloped by high-energy ions that can damage satellites and even interfere with electronics on the ground. Now, new satellite data show that most of those nefarious ions originate in our planet's own protective atmosphere.
A space storm starts with a gust of particles flowing from the sun. Earth's magnetic field deflects this solar wind, but not before it blows oxygen ions from the atmosphere into space. These ions and particles from the solar wind then collect in a long tail of magnetic fields stretching away from Earth. The tail occasionally snaps back, surrounding Earth in a vast doughnut-shaped cloud of particles called the ring current. Particles from the ring current then rain down, creating a hazard for satellites. But how much of the ring current originates in the solar wind, and how much comes from ions blown out of the atmosphere, has been an open question.
Now, NASA's Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) has given researchers their first bird's-eye view of entire space storms, and the new vantage makes clear that Earth's atmosphere plays an active role. IMAGE's orbit takes it high above the North Pole, far enough away to watch tons of oxygen ions flow out into space, collect in the magnetic tail, and boomerang back. As it turns out, these oxygen ions make up most of the ring current, IMAGE researchers reported on 9 May at a press conference at NASA headquarters in Washington, D.C.
IMAGE data could be a boon to researchers developing computer models to forecast space weather, says Terry Onsager of the National Oceanic and Atmospheric Administration's Space Environment Center in Boulder, Colorado: "This kind of result will help us to understand ... what kind of measurements we need to look at to feed our models more accurately."