Astronomy Picture of the Day
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
November 5, 1995
Vela Satellites: The Watchers
In October of 1963 the
US Air Force
launched the first in a series of
satellites inspired by a recently signed
nuclear test ban treaty.
Signatories of this treaty agreed not to test nuclear devices in the
atmosphere or in space. These "Vela" (from the
Spanish verb velar,
to watch) satellites were part of an unclassified
program whose goal was to develop the technology to monitor
nuclear tests from space.
Vela satellite is pictured above in an artist's conception, keeping
watch over the Earth. The high energy radiation sensors onboard
the Velas did not detect any
clandestine nuclear explosions.
Instead, in the most
surprising discovery in the history of
space based astronomy, they found
bursts of gamma rays coming from deep space!
The mysterious origin of these brief, intense flashes of gamma rays
is one of the most
hotly debated topics in modern astrophysics.
Tomorrow's picture: M16: Stars Upon Pillars
| About APOD
Authors & editors:
NASA Technical Rep.:
Specific rights apply.
A service of:
Michigan Tech. U.