Astronomy Picture of the Day
Discover the cosmos! Each day we feature a different image or photograph
of our fascinating universe, along with a brief explanation written by a
January 2, 1996
The X-Ray Sky
Boldt (GSFC) and
Garmire (Cal Tech/PSU),
What if you could see
If you could, the
night sky would be a strange and unfamiliar place.
X-rays are about 1,000 times more energetic
than visible light photons and are produced in violent and high
temperature astrophysical environments. Instead of the familiar
steady stars, the sky would seem to be filled with
exotic binary star systems
composed of white dwarfs,
neutron stars, and
black holes, along with
flare stars, X-ray bursters,
supernova remnants and
This X-ray image of the entire sky was constructed with
using data from the first
High Energy Astronomy Observatory (HEAO 1),
and plotted in a coordinate system centred on the galactic centre
with the north galactic pole at the top.
Sources near the galactic centre are seen to dominate in this
false colour map which shows regions of highest X-ray intensity in yellow.
Astronomers' ability to observe the sky at X-ray energies
will be greatly enhanced by the recently launched
X-ray Timing Explorer (XTE) satellite.
Tomorrow's picture: The X-ray Timing Explorer
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