An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum. This emission may arise in molecular clouds, comets, planetary atmospheres, stellar atmospheres, or various other conditions in interstellar space.
Aurorae on the north pole of Jupiter generate cyclotron masers (Hubble)
Pulsations of the Mira variable S Orionis, showing dust production and masers (ESO)
WISE image of IC 443, a supernova remnant with maser emission
Charles Hard Townes was an American physicist. Townes worked on the theory and application of the maser, for which he obtained the fundamental patent, and other work in quantum electronics associated with both maser and laser devices. He shared the 1964 Nobel Prize in Physics with Nikolay Basov and Alexander Prokhorov. Townes was an adviser to the United States Government, meeting every US president from Harry S. Truman (1945) to Bill Clinton (1999).
Townes in 1983
Daughters of Townes in Sweden in 1964
Townes (right) receiving the 1964 Nobel Prize