Neutron star between 10 and 10 (100 million to 1 quadrillion) times as strong as that of the Earth. The gravitational field at the neutron star's surface is about (200 billion) times that of the Earth. As the star's core collapses, its rotation rate increases as a result of conservation of angular momentum, hence newly formed neutron stars rotate at up to several hundred times per second. Some neutron stars emit beams of electromagnetic radiation that make them detectable as pulsars. Indeed, the discovery of pulsars by Jocelyn Bell Burnell in 1967 was the first observational suggestion that neutron stars exist. The
Relativistic beaming accreting compact object, but are thought to be merely a particular variety of AGN.) Beaming (short for relativistic beaming) affects the apparent brightness of a moving object just as a lighthouse affects the appearance of its light source: the light source appears dim or unseen to a ship except when the rotating lighthouse beacon is directed towards a ship, where it then appears very bright. This so-called lighthouse effect illustrates how important the direction of motion (relative to the observer) is in relativistic beaming: if a blob of gas emitting electromagnetic radiation is moving towards the observer then it will