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Pulsars, Black Holes and Gravitational Waves

A pulsar is the remnant core of a star that has undergone a supernova explosion.

A pulsar is the remnant core of a star that has undergone a supernova explosion. The pulsar’s extremely strong magnetic field accelerates particles to almost the speed of light. As these relativistic particles stream away from the pulsar, they produce focused beams of radio emission. Astronomers study these objects with the aim of discovering ripples in space and time known as gravitational waves. Credit: Swinburne Astronomy Productions

By George Hobbs

The SKA will be able to study thousands of pulsars in sufficient detail to detect gravity waves.

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In 1915 Albert Einstein published his general theory of relativity, which states that massive objects such as black holes cause a distortion in space–time that is felt as gravity. If such objects accelerate, such as two black holes orbiting each other, then the space–time warping propagates outwards as a gravitational wave.

How can we prove or disprove Einstein’s theory, and how can we detect those elusive gravitational waves? The answer comes from some intriguing objects known as pulsars.

Pulsars really are extreme. They have more mass than our Sun, but compressed into a star about the size of Sydney.

Pulsars have huge magnetic fields – about a million times stronger than the most powerful magnetic field ever achieved in a laboratory on Earth – and the north and south poles of this magnetic field accelerate particles to almost the speed of light. These particles emit narrow beams of radiation as they stream away from the pulsar.

Some pulsars spin so fast that their surface is moving close to the speed of light. As the pulsar rotates, its radiation beams sweep across our line of sight and are detected by radio telescopes as a series of pulses. For this reason, pulsars are often described as celestial lighthouses.

Pulsars can be studied for their own unique and exciting properties. However, since they produce a radio pulse every time...

The full text of this article can be purchased from Informit.