Is cosmic string the radio burst culprit?
LIKE a shout in the dark, a mysterious burst of radio waves from the depths of space has puzzled astronomers since it was discovered last year. Now one physicist is suggesting it came from the cosmic equivalent of a cracking whip. In 2001, a radio burst lasting about 1 millisecond was picked up by the 64-metre Parkes radio dish in Australia. The signal went unnoticed at first, but last year a team led by Duncan Lorimer of West Virginia University, Morgantown, spotted it during a recap of archived observations. By analysing the time delays of different frequencies within the burst, they found it had travelled a huge distance – about 3 billion light years. The presence of a supernova, gamma-ray burster or galaxy would have explained its origin, but curiously none lies in that part of the sky. Though it is possible a stellar object such as a pulsar was …
