Ten years ago, an AT&T TV satellite cut out without warning, cutting off service to millions of people. Six days later, it was declared permanently dead.
Scientists subsequently decided it had been knocked out of commission by something called a coronal mass ejection (CME), a burst of accelerated, charged particles or plasma from the Sun. It has long been clear that this kind of solar belching can be harmful to satellites or even power grids as the effluvia flows across the Earth's orbit – but the mechanism of the process hasn't been well understood.
Now scientists working with Europe's Cluster satellites have made progress in understanding how those potentially dangerous streams of particles are accelerated by interacting with the region surrounding the Earth itself.
Based on satellite data and simulations, the scientists say that these particles can be ejected at the speed of the solar wind; but when they reach Earth, the solar wind's magnetic lines back up against the planet's own magnetosphere before sliding sideways and accelerating the plasma like a "magnetic slingshot," the researchers write.
This winds up shooting bunches of matter past the planet at speeds of
1000 km/s (about 620 miles per second). That may be slow compared to the massless photons whizzing by, but for particles with mass, it gives them momentum enough to be potentially damaging to electronics in their way.
The mechanism which releases these bursts of particles (which are different than, but often associated with, solar flares) from the sun still isn't well understood.
Solar outburst pulls a magnetic slingshot [ESA]
(Image: A coronal mass ejection recorded in 2000 by the Solar and
Heliospheric Observatory (SOHO), with sun's direct light blocked out. Credit: SOHO Consortium, ESA, NASA)
