Gamma Ray Moon
Explanation:
What if you could see gamma rays (photons with more than 40 million
times the energy of visible light)?
If you could, the Moon would appear brighter than the Sun!
This startling notion is demonstrated by this image of the Moon from the
Energetic Gamma Ray Experiment Telescope (EGRET)
onboard NASA's orbiting
Compton Gamma Ray Observatory.
The most sensitive instrument of its kind, even EGRET can not see
the quiet Sun which is faint
at extreme gamma-ray energies.
Why is the Moon so bright in gamma rays?
High energy charged particles
known as cosmic rays,
constantly bombard the unprotected
lunar surface generating gamma rays.
EGRET's gamma-ray vision is not sharp enough to resolve a lunar
disk or any surface features but its sensitivity reveals the bright
gamma-ray
moonglow
against a background of gamma rays from
our Milky Way galaxy,
gamma-ray quasars
and some still
mysterious unidentified sources.
The image was generated from eight exposures
made during 1991-1994.
A wide-angle picture, it covers a roughly 40x40 degree field of view
with gamma-ray intensity represented in false color.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
