Gamma Ray Earth and Sky
Explanation:
For an Earth-orbiting gamma-ray telescope,
Earth is actually the brightest source of
gamma-rays, the most energetic form of light.
Gamma-rays from Earth
are produced when high energy particles,
cosmic rays
from space, crash into the atmosphere.
While that interaction blocks harmful radiation from
reaching the surface, those gamma-rays dominate
in this remarkable Earth and sky view
from the orbiting
Fermi
Gamma-ray Space Telescope's Large Area Telescope.
The image was constructed using only observations
made when the center of our Milky Way galaxy was near the zenith,
directly above the
Fermi satellite.
The zenith is mapped to the center of the field.
The Earth and points near the nadir, directly below the satellite,
are mapped to the edges of the field resulting
in an Earth and all-sky projection
from Fermi's orbital perspective.
The color scheme shows low intensities of gamma-rays
as blue and high intensities as yellowish hues on a
logarithmic scale.
Our fair planet's
brighter gamma-ray glow floods the edges of field,
the high intensity yellow ring tracing Earth's limb.
Gamma-ray sources
in the sky along the relatively faint Milky Way
stretch diagonally across the middle.
Launched June 11, 2008 to
explore the
high-energy Universe,
this week Fermi celebrated its 2,000th day in low Earth orbit.
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.
