The ray attack

Powerful rays from the edge of the Universe reach Earth

 
Published: Saturday 31 October 1998

A PHYSICIST from USA and an astronomer from Germany argue that cosmic rays of exceptional power have reached earth from outermost edges of the Universe. They made this observation after studying five most energetic cosmic rays that came from five extremely distant quasars, objects at the very edge of the universe.

This conclusion, if proved, will be significant because it will strengthen theories that there may be a new subatomic particle. "No known particle could have survived such a long journey," says Glennys Farrar, a researcher at the Rutgers University in New Jersey, USA.

Particles that form ultra-high energy cosmic rays travel through space and as they collide with the photons, they loose some of their energy. Because of this loss of energy, even particles which had energy greater than 1020 electronvolts (ev) should not theoretically be able to travel more than 150 million light years, and those which originate further away should not reach the Earth.

Farrar and Peter Bierman of the Max Planck Institute for Radio Astronomy in Bonn, Germany, have studied the data on the rays. All the rays selected have energies greater than 1020ev.

The result showed that all the rays appear to be coming from quasars which are more than 150 million light years away.

But when confronted by the question, how the cosmic rays could have crossed such distances towards Earth, Farrar says that these rays may contain a new particle and it maybe, what is called the So - a peculiar hybrid consisting of a normal up, down and strange quark bound to a gluino.

According to Farrar, every known particle has a superpartner and gluino is the superpartner of gluon. Farrar further adds that So would be neutral and less likely to interact with the big-bang photons and it is quite capable of travelling across thousands of millions of light years.

"It is a very exciting possibility", says David Hough of Trinity University in San Antonio, USA. "We are talking about pieces of quasars actually falling to Earth, he adds.

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