2008-08-27

A new space telescope, launched less than three months ago and now flying in orbit 350 miles above the Earth, is detecting powerful bursts of mysterious energy from stars and galaxies far beyond the Milky Way, an international team headed by a Stanford physicist reported Tuesday.

Named in honor of the late Enrico Fermi, a pioneer in the field of particle physics, the telescope is scanning the sky every three hours for sources of invisible gamma rays that cannot penetrate Earth's atmosphere but are the most extreme known form of high-energy radiation.

The scientists believe that what the Fermi instrument discovers in the near future could well challenge basic theories of the universe, its structure and its origins.

To Peter Michelson of Stanford, leader of the team, the sky studded with gamma-ray bursts is "very much like the sky at a Fourth of July celebration, but we're seeing it on a cosmic scale."

Michelson and other members of the telescope team described their first observations from the telescope during a conference call with reporters Tuesday, and their excitement was palpable as they told of seeing distant high-energy objects known from previous orbiting telescopes, but never before seen in the gamma-ray frequency of the electromagnetic spectrum.

"And we're going to see deeper into our universe than ever before," Michelson said.

Originally named GLAST for Gamma-ray Large Area Space Telescope, the Fermi spacecraft was launched in June from Cape Canaveral, and its performance has been tested and checked minutely as it orbits the Earth.

"Everything has worked as expected and then some," said Steven Ritz, the NASA project scientist at the Goddard Space Flight Center in Greenbelt, Md. "None of us could have asked for such a smooth turn-on, it went like clockwork."

The spacecraft carries two major instruments - one called the Large Area Telescope is the Michelson team's specialty, and its conceptual design was the work of William Atwood, a UC Santa Cruz physicist.

The other instrument is the Gamma-Ray Burst Monitor, which is tuned to catch every cosmic blast of gamma radiation that bursts from mystery objects in the sky - collisions of nuclear matter with high-energy cosmic rays, active galaxies flaring into monstrous bursts of energy, black holes, quasars, pulsars and still-unidentified objects in the cosmos.

Out of all these sightings, Michelson said, his team of 270 scientists from seven nations expects to find unknown sub-nuclear particles that may well be the long-sought and still hypothetical particles sometimes known as WIMPs, for Weakly Interacting Massive Particles.

These unseen particles, whatever they are, are thought by many scientists to make up the mysterious "dark matter" that has never been detected but is known from the unseen effects of its gravity and may make up most of the total mass of the universe - far more than the ordinary matter all around us.

An earlier spacecraft, the Compton Gamma Ray Observatory, found more than 270 high-energy objects more than a decade ago before it was shut down, but the new Fermi Space Telescope has been given a five-year mission and its scientists expect it to continue its work for a full decade.

After two months of testing and instrument calibration, Michelson said he and his team are elated over the prospects of discoveries they can't even predict.

Already, he said, the telescope's "all-sky" images of gamma radiation have shown gas and dust in the plane of the Milky Way glowing from collisions with high-energy cosmic rays, as well as several pulsars - swiftly rotating neutron stars - that had been seen by earlier space telescopes.

The Fermi spacecraft has also detected gamma rays from the sudden flaring of an active galaxy called a "blazer" more than 7 billion light-years away in the constellation Pegasus, and another blazer more than 10 billion light-years away, Michelson reported.

The $700 million telescope is jointly funded by NASA and the Department of Energy.

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