Boundaries of the Universe

13. Pulsars

 

We have seen how the quasars have proved extremely useful in investigations of the solar wind, vast clouds of charged particles hurled out into space by the Sun. The radio waves from extra-galactic radio sources are distorted as they pass through these ‘plasma clouds‘, as they are called, but only if the source itself has very small angular dimensions. The ordinary radio galaxies such as the Seyfert galaxies already described – and even the radio sources within our own Galaxy – have dimensions that are much too large to cause this scintillation, which may be compared with the twinkling of starlight due to its passage through the atmosphere.

The discovery of the first pulsar by Hewish and his co-workers came in 1967 during an investigation ...