Nearest pulsar

PSRJ0108-1431, in the constellation of Cetus, is 280 light years (85 parsecs) away. The radiation beams from this pulsar are extremely weak and its age has been estimated to be around 160 million years. This is the closest pulsar to Earth yet discovered.

Pulsars are formed by the catastrophic deaths of massive stars. These supernova explosions leave behind a relic of the star's core – a neutron star. These superdense cosmic objects are only the size of a large city, but they contain as much mass as the whole of the Sun. They are composed of neutrons that are all squashed up against each other (normally the gaps between atomic nucleii are very large compared to the size of the nucleus), giving rise to a density so great that a teaspoon full would weigh a staggering thousand million tonnes!

Some neutron stars emit beams of radiation as they rapidly rotate. If the Earth lies along the axis of these beams, we see the neutron star flash on and off as it rotates. These neutron stars are known as pulsars – short for pulsating stars.