By Ron Cowen
Editor’s note: This story was updated February 19 after Michael Briggs of NASA’s Goddard Space Flight Center in Greenbelt., Md., reported that the gamma-ray burst known as GRB 080916C is the most energetic burst known.
VANCOUVER, Canada — Curtain up! Light the lights! In its first four months of monitoring the heavens from orbit, NASA’s Fermi Gamma-ray Space Telescope has unveiled the activity of celestial objects that emit powerful gamma rays — photons that pack 20 million to more than 300 billion times the energy of visible light. The orbiting observatory features the first detectors in space capable of recording the most energetic of these photons.
For now, Fermi’s flurry of first findings — which include new discoveries about gamma-ray bursts as well as the energetic radiation emitted by rapidly spinning stellar corpses called pulsars, several never before recorded — poses new puzzles. But ultimately the discoveries will offer new insight into the origin of these powerful emissions and the activity of some of the most enigmatic objects in the cosmos, says Peter Michelson of Stanford University, principal investigator of Fermi’s Large Area Telescope, the device on the observatory that records the high-energy emissions.