Fwd: News: A Disturbance in the Neighborhood
- --- In email@example.com, "Robert Karl Stonjek"
Hot spots. Astronomers have spotted two zones (in red) of high-energy
cosmic rays coming from the direction of Orion.
Credit: John Pretz/Los Alamos National Laboratory
A Disturbance in the Neighborhood
By Phil Berardelli
ScienceNOW Daily News
24 November 2008
Something strange may be going on around Orion. Somewhere near that
familiar constellation, two unknown sources seem to be showering Earth
and the rest of the Milky Way with galactic cosmic rays, astronomers
report today. The findings could shed light on one of the biggest
mysteries in the universe.
The term "cosmic rays" is somewhat of a misnomer. The "rays" consist
mostly of solid protons, not the photons that make up light. These
particles whiz around the cosmos at near-light speed, causing all
sorts of mischief when they penetrate Earth's magnetic field.
Scientists blame them for everything from computer-memory glitches to
bolts of lightning. In space, the rays would pose a health hazard to
astronauts on interplanetary missions, as they can mutate our DNA
(ScienceNOW, 4 November).
Despite decades of study, researchers still don't know the basics
about cosmic rays, including what causes them and where they come
from. Supposed sources include supernovae, quasars, and black hole
collisions (ScienceNOW, 4 October 2007). But until now, no one has
connected cosmic-ray generation to a single event. And no one has been
able to pinpoint a source; cosmic rays seem to emanate more or less
consistently from all over the sky.
Or perhaps not, a team from 16 institutions reports in Physical Review
Letters. Using the Milagro observatory in Los Alamos, New Mexico,
which detects cosmic-ray particles when they collide with water
molecules in a pool on the ground, the researchers compiled nearly 7
years' worth of data on about 220 billion cosmic-ray collisions. Based
on those data, the researchers have found that two swaths of sky over
the Northern Hemisphere--about where Orion sits--seem to be producing
more cosmic rays than any other. The difference isn't much--about
0.06% and 0.04%, respectively--but it's enough to stick out from the
background activity. So far, the researchers say, they have ruled out
the possibility of the zones being somehow caused by our sun or by the
direction of the rays being warped by Earth's magnetic field. Other
than that, however, the book is still open about what's causing these
rays in the first place.
Astrophysicist John Wefel of Louisiana State University in Baton
Rouge, who authored a paper in last week's issue of Nature describing
a similar discovery involving high-energy-electron cosmic rays, says
both findings should stimulate a determined search for candidate
sources. "It's not like [the hot spots] are standing way out from the
background," he says, "but the fact that they're there at all is
The editors suggest the following Related Resources on Science sites:
Solar Storm! Shields Up!
Phil Berardelli (4 November 2008)
ScienceNOW 2008 (1104), 1.
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Tracing the Trail of Cosmic Rays
Phil Berardelli (4 October 2007)
ScienceNOW 2007 (1004), 5.
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Robert Karl Stonjek
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