Gamma-Ray Earth and Sky
Image Credit: International Fermi Large Area Telescope Collaboration, NASA, DOE)
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. (underline added) (source - http://apod.nasa.gov/apod/)
Alpha radiation consists of helium nuclei and is readily stopped by a sheet of paper. Beta radiation, consisting of electrons or positrons, is halted by an aluminum plate. Gamma radiation is dampened by lead.
Gamma-rays - are the frequency of DC current. [see Westinghouse Electromagnetic Chart wherein this relationship is shown.]
Gamma rays (also called gamma radiation), denoted by the lower-case Greek letter gamma (γ or
γ\gamma ), are penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei. It consists of photons in the highest observed range of photon energy. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation gamma rays. Rutherford had previously discovered two other types of radioactive decay, which he named alpha rays and beta rays.
The decay of an atomic nucleus from a high energy state to a lower energy state, a process called gamma decay, produces gamma radiation.
Gamma rays ionize atoms (they are ionizing radiation), and are thus biologically hazardous. Wikipedia, Gamma Ray
15.08 - Dissociating Water with X-Rays - Radiolysis