Geminga

Geminga is a neutron star in the Gemini constellation, about 500 light years away from Earth. The name derives from "GEMINi GAmma ray source". Discovered in 1972 by the satellite SAS-2, Geminga is the second brightest gamma ray source in the skies with over 100 MeV. In 1992 the ROSAT satellite detected a radiation periodicity of 0.237 seconds. Unlike other known pulsars, Geminga does not emit in the radio frequency range. It is the Earth?s closest known pulsar.

Geminga was formed about 300,000 years ago in a supernova explosion. Some theories say that this explosion is the cause of the relatively low interstellar material density in the vicinity of the Sun (local bubble).