Long before experiments could detect gamma rays emitted

Long before experiments could detect gamma rays emitted

Most gamma rays coming from space are absorbed by the Earth's atmosphere, STK411-550G so gamma-ray astronomy could not develop until it was possible to get detectors above all or most of the atmosphere using balloons and spacecraft. The first gamma-ray lpg-899 telescope carried into orbit, on the Explorer 11 satellite in 1961, picked up fewer than 100 cosmic gamma-ray photons. They appeared to come from all directions in the Universe, implying some sort of BA9741F uniform gamma-ray background. Such a background would be expected from the interaction of cosmic rays (very energetic charged particles in space) with interstellar gas.The first true astrophysical gamma-ray sources were solar flares, which revealed AAT4618IGV-1.0-T1 the strong 2.223 MeV line predicted by Morrison. This line results from the formation of deuterium via the union of a neutron and proton; in a solar flare the neutrons appear as secondaries from interactions of high-energy ions accelerated Ds1287 in the flare process. These first gamma-ray line observations were from OSO-3, OSO-7, and the Solar Maximum Mission, the latter spacecraft launched in 1980. The solar observations inspired theoretical work by Reuven Ramaty and others.