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N.M. astronomers use lens to travel back in time
Scripps Howard News Service


January 14, 2006

Some things just aren't supposed to change.

Things like the speed of light, the mass of a proton and the charge of an electron should be immune to changes over time.

Astronomers working with the National Radio Astronomy Observatory in Socorro, N.M., are trying to find out if that's the case. To do so, they're studying some of the oldest objects in the universe.




"Telescopes are like time machines: The further we look out into space, the further we look back in time," said John Stocke, an astronomy professor at the University of Colorado who is working with the observatory.

Stocke, astronomer Chris Carilli, and others looked at fundamental constants in a 6.5-billion-year old galaxy far from our own and compared them with today's constants.

They have been studying the objects for a year. Their findings were published in the Dec. 31 issue of the journal Physical Review Letters.

They've found that the constants remained, well, constant, Carilli said.

Not finding a change doesn't necessarily mean the constants haven't changed.

The universe is about 12 billion years old, and radio astronomers haven't looked for the constants further back than the 6.5-billion-year-old galaxy so far, Stocke said.

"There may have been really rapid changes in the early universe, and if we find them, we need to look back further at how those changes may have affected stars and galaxies," Stocke said.

Changing constants could alter astrophysicists' ideas about the shape of the universe and how it grew, Stocke said.

Optical telescopes - those that rely on sight - have had mixed results looking for proof of changing constants.

The other type of telescope, a radio telescope, which the observatory uses, detects radio waves emitted by distant objects. In the past, radio telescopes weren't as sensitive as they are today, so they haven't been used to do full-sky surveys until now.

The body of information should improve during the next year, as astronomers like those at the observatory use radio telescopes to map more of the sky and find more of the oldest galaxies in the universe, Stocke said.

Only one in 10,000 objects has features that astronomers need to be able to study if the constants are changing.

But improved radio telescope technology means the story of the constants will be clearer in the coming few years, Stocke said.

"We're hot in pursuit. It's just a matter of finding the right source," he said.


Contact Sue Vorenberg of The Tribune in Albuquerque, N.M., at
Distributed to subscribers by Scripps Howard News Service.

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