Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
March 15, 1997
Explanation: Although the Earth is round, our Galaxy appears
truly flat. This was shown in dramatic fashion by the COsmic Background Explorer (COBE)
satellite which produced this premier view of the central region
of our own Milky Way Galaxy
in infrared light in1990. The Milky Way
is a typical spiral galaxy with a
central bulge and extended disk of stars. However, gas and dust
within the disk obscure visible wavelengths of light effectively
preventing clear observations of the centre. Since infrared
wavelengths are less affected by the obscuring material, the Diffuse InfraRed Background Experiment (DIRBE)
on board COBE
was able to detected infrared light from stars surrounding the Galactic centre
and produce this image. Of course, the edge on perspective represents
the view from the vicinity of our Sun,
a star located in the disk about 30,000 light years out from the
centre. The DIRBE
module used equipment cooled by a tub of liquid helium to detect
the infrared light which, composed of wavelengths longer than red light,
is invisible to the human eye.
Authors & editors:
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.