Scientist unlocks gamma ray burst secrets

Gamma ray bursts are intense explosions of light and are among some of the brightest events that have ever been observed in the universe. However, because they occur in short bursts and originate in distant galaxies -- sometimes even billions of light years from Earth -- scientists have not been able to exactly pinpoint what causes them.

Some might even suggest they may be messages from advanced alien civilisations but many experts have predicted that the bursts are emitted when jets of particles are thrown out by massive astrophysical objects, such as black holes. For this theory to work, the beams released by black holes would have to have strong, self-generated magnetic fields and the rotation of particles around the fields would then give off powerful bursts of gamma ray radiation.

Dr Gianluca Sarri from the School of Mathematics and Physics at Queen's University has led an international team of researchers to create the first small-scale replica of gamma ray bursts. He has now been able to prove for the first time, some of the key phenomena that play a major role in producing gamma ray bursts.

The researchers made use of the Gemini laser, the most intense laser on Earth, to create the mini gamma ray burst.

Dr Sarri explains: "We thought that the best way to work out how gamma ray bursts are produced would be to mimic them in small-scale reproductions in the laboratory -- reproducing a little source of these beams and look at how they evolve when left on their own.

"During the experiment, we were able to confirm that the current models used to understand gamma ray bursts are on the right track, predicting the right mechanisms for the magnetic field generation and gamma-ray emission.

"The experiment is also useful as the beams are entirely made up of electrons and positrons, which is a peculiar state of matter. In an electron-positron beam, both particles have exactly the same mass, leading to fascinating consequences. For example, sound would not exist in an electron-positron world."

The research, which has been published in Physical Review Letters, could also unlock some major clues in the search for alien life. The Search for Extra-Terrestrial Intelligence investigation looks for messages in space that cannot be explained naturally and that could potentially be originating from an alien civilisation.

"If you really want to search the universe for alien transmissions, you first need to make sure all the natural emissions are understood so that they can be ruled out. Our study helps towards understanding black hole and pulsar emissions, so that, whenever we detect anything, we can determine straight away if it can be explained naturally or if it has come from an alien civilisation."