aurora borealis

NASA funds $173 million auroral satellite mission

NASA has awarded the University of California, Berkeley, a $173 million contract to build and operate a fleet of five satellites to pinpoint the event in Earth’s magnetic neighborhood that triggers violent but colorful eruptions in the Northern and Southern lights. The aurora borealis and aurora australis are shimmering light shows that brighten the polar nights, generated by showers of electrons descending along magnetic field lines onto the poles. These high-speed electrons spark colored lights as they hit the atmosphere, much like a color TV lights up when an electron beam hits the phosphorescent screen.

Magnetic ‘slinky effect’ may power aurora

The spectacular aurora borealis displays that light up the northern nights could be powered by a gigantic “slinky” effect in Earth’s magnetic field lines, according to research performed at the University of Minnesota. Earth’s magnetic field resemble a slinky in that when “wiggled,” it undulates in waves that travel down the field lines at speeds up to 25 million miles per hour. These waves can pass energy to electrons, accelerating them along the magnetic field lines toward Earth. When the electrons hit atoms in the atmosphere, the atoms become excited and produce the colors of the aurora. Using electric and magnetic field data and images from NASA’s POLAR satellite, the researchers showed that energy from such waves is sufficient to power auroras and that statistically, the waves occur in the same locations as auroras–in a ring around the poles. The work will be published in the Jan. 17 issue of Science.