Scientists witness massive gamma-ray burst, don't understand it

Scientists have studied gamma-ray bursts, which are triggered by the collapse of massive stars, for three decades. Now, one is forcing them to reconsider what they thought they knew.

An exploded star some 3.8 billion light-years away is forcing scientists to overhaul much of what they thought they knew about gamma-ray bursts – intense blasts of radiation triggered, in this case, by a star tens of times more massive than the sun that exhausted its nuclear fuel, exploded, then collapsed to form a black hole.

Last April, gamma rays from the blast struck detectors in gamma-ray observatories orbiting Earth, triggering a frenzy of space- and ground-based observations. Many of them fly in the face of explanations researchers have developed during the past 30 years for the processes driving the evolution of a burst from flash to fade out, according to four research papers appearing Friday in the journal Science.

“Some of our theories are just going down the drain,” said Charles Dermer, an astrophysicist at the Los Alamos National Laboratory in New Mexico and a member of one of the teams reporting on their observations of the burst, known as GRB 130427A.

The event, dubbed a long-duration gamma-ray burst (GRB), is typically seen in the distant, early universe, Dr. Dermer said during a briefing Thursday. This one was much closer. And while typical long-duration bursts last from a few seconds to a few minutes, GRB 130427A put on its display for 20 hours.

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