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Physicists use telescopes to hunt for extra terrestrials

PR08(07)

Tue, 22 May 2007

Telescopes are normally used to look at the sky and help scientists learn more about objects in space such as black holes. However researchers at the University of Leeds, together with colleagues in the United States of America, have been searching data from a Cherenkov telescope in Arizona to search for evidence of extra terrestrials. They will present their findings¹ at the Nuclear and Particle Physics conference organised by the Institute of Physics on Wednesday 4 April 2007.    

The main task of imaging Cherenkov telescopes is to detect high-energy gamma rays emitted from objects in space. However, they are also efficient detectors of optical signals that could originate from extra-terrestrial civilizations, although not designed for this purpose.

Dr Joachim Rose at LeedsUniversity said: “The Whipple telescope has an ultra high-speed camera to record faint flashes of light from cosmic rays and from high-energy gamma rays entering the Earth’s atmosphere. There are 20 to 30 naturally occurring light flashes recorded every second.  A few unusual images from extraterrestrial’s signals would be easy to miss as the analysis software normally rejects anything that it doesn’t expect.”

The researchers have so far studied over 2000 hours of archival telescope data looking for unusual images. They have found images of light flashes that appear to originate from areas around stars similar to the Sun, which could indicate the existence of life on other planets. 

Dr Rose continued: “On average we see such an unusual flash every six hours when pointing in the direction of one of these candidate stars. However, this is comparable to the rate of similar flashes in other regions of the sky where there is no candidate star.”

His colleague Dr Stella Bradbury quoted astronomer Frank Drake: “absence of evidence is not evidence of absence”. She continues: ”So far only a minute fraction of the sky has been searched and arrays of telescopes can carry out much more sensitive searches than a single telescope”.

The researchers plan to continue their search when a new array of telescopes opens at the same site in Arizona later this month. Telescopes in an array can cross check each other so can carry out much more sensitive searches for signals than a single telescope.  They can also search much wider areas of the sky so it will no longer be necessary to restrict the search to a list of candidate stars.

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