New class of gamma rays discovered in Milky Way
Impression of the line of sight straight down a gas jet produced by a black hole, which may be the source of gamma-ray glows
GREENBELT, Maryland (CNN) -- Astronomers have detected a new
class of gamma rays coming from a mysterious source or
sources within our own galaxy.
Gamma rays are invisible to the eye, but are the most
powerful form of light, far exceeding visible light,
ultraviolet radiation and X-rays.
There are 271 known sources of gamma rays in the universe,
which before this discovery were thought to originate in the
distant reaches of the universe, far beyond the Milky Way.
Those distant sources emit gamma
rays in sudden bursts.
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But research published in the journal Nature this week by
NASA astrophysicist Neil Gehrels and colleagues suggests the
170 of the gamma ray sources are located within our Milky
Many could reside in Gould Belt
"These are objects we've never seen before," Gehrels said. "We can't make out what they are yet, but we
know they're strange and, boy, there's a lot of them. These
are very different than the famous gamma-ray burst sources,
because the gamma rays shine continuously instead of coming
in a flash like the gamma-ray bursts."
Many of these nearby sources seem to originate from a region
in the Milky Way called the Gould Belt, an area containing
massive stars and gas clouds.
In this image, the bright areas are gamma ray sources detected by the Compton observatory are overlaid on a map of the entire celestial sphere that has been projected on a
flat, two-dimensional plane. In reality, the gamma sources surround us.
Other gamma ray sources in our galaxy are closer to the Earth
and considered a new class of objects, said Gehrels, who
works for NASA's Goddard Space flight Center in Greenbelt,
Scientists are still struggling to understand what types of
objects emit these gamma rays. Potential candidates include
black holes, massive stars, neutron stars and clusters of
pulsars. But more research is required to determine the
sources, the astronomers said.
Final curtain for gamma ray hunter?
Gamma rays are about 100 million times more powerful than
visible light, but they pose no danger to terrestrial life.
Discovery of the gamma ray sources is based on data collected
from the orbiting Compton Gamma Ray Observatory. After nearly
a decade in space, the observatory has lost two of its three
gyroscopes needed to keep it properly aligned in orbit.
NASA will hold a meeting Thursday to determine the fate of
the satellite. The space agency is considering taking the
35,000-pound spacecraft out of orbit in a controlled re-entry
into the Pacific Ocean, off the coast of Hawaii.
Much of it would burn up in the atmosphere, but pieces could
survive re-entry and fall to Earth. NASA will announce its
Huge NASA telescope may be headed for fiery descent to splash landing
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CGRO Public Relations
NASA: Structure and Evolution of the Universe
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