NOTE TO REPORTERS AND EDITORS: Story embargoed for release until 2 p.m.
PST on Monday, December 10, 2001
Researchers have known for three decades that the Earth is a tremendous
radio transmitter, but they were never able to pinpoint where the noise
was coming from. Using the quartet of spacecraft from the Cluster
mission, scientists have been able to precisely locate the sourse of
that radio noise along magnetic field lines several thousand miles above
bright regions in the aurora. In another finding, researchers using
instruments on Cluster have made the first close-up measurements of the
formation of electrical structures known as the "black aurora,"
comparable to a photographic negative of the aurora. Researchers have
found evidence of electrons being accelerated away from the upper
atmosphere into space, creating holes in the ionosphere.
NASA Press Release: Cluster Tunes Into Earth^(1)s Frequency, Pinpoints
Location of Auroral Radio Emissions
ESA Press Release: Cluster Quartet Probes the Secrets of the Black
ESA Public Page about the black aurora
Images and movies from the press
Audio-visual (Shockwave) clip of Auroral Kilometric Radio (AKR) burst
emission received on Cluster spacecraft 1 (Rumba) and 3 (Samba) at 02:14
UT on July 28, 2001
Listen to the sounds of the aurora and
Click here for a PDF version of "Temporal evolution of the electric
field accelerating electrons away from the auroral ionosphere" by G.T.
Marklund et al, to be published in Nature on December 13.
Presentations related to this news, delivered at a press conference at
the Fall Meeting of the American Geophysical Union
Background information on auroras and the Cluster Mission