nova presents deathstar january 8, 2002

A long time ago in a galaxy far, far away, a gigantic explosion sent gamma-rays racing toward Earth to arrive in 1967 and set scientists wondering what in heaven could produce so much energy. NOVA joins the thirty-year quest to solve this strange riddle, on Death Star, airing Tuesday, January 8, 2002, at 8 PM ET on PBS (check for local listings).

The mystery leads from a chance discovery, to a perplexing search for answers, to a raft of crazy theories, to an array of new tools, and finally to a climactic race to get the last crucial pieces of the puzzle and find the utterly surprising perpetrator. In other words, it's a rousing good detective story.

It all started in 1967 with a new series of satellites designed to monitor compliance by the Soviet Union and other nations with the Nuclear Test Ban Treaty. Called Vela, the Earth-orbiters watched for telltale bursts of gamma-rays produced by nuclear explosions.

However the brightest gamma-ray signals were not coming from Earth but from seemingly random spots in space.

Scientists were so baffled that after they announced the discovery journalists were virtually the only ones who would venture explanations. "The National Enquirer thought that maybe we were seeing alien civilizations warring with each other and throwing nuclear bombs," says Gerald Fishman, an astrophysicist at the NASA Marshall Space Flight Center. "They even got a respectable scientist to say, `Well, yeah, I guess that's a possibility.'"

In fact, the gamma-ray bursts were not characteristic of nuclear explosions at all, but of something completely unknown. Whatever it was had to be of phenomenal violence. Most mysterious of all was that when astronomers steered optical telescopes and other sensitive detectors to the spots where the radiation had originated there was no sign of anything.

Since light energy diminishes with the distance from the source, many scientists concluded that the gamma-ray bursts must be relatively nearby in space, probably within our Milky Way galaxy. These scientists found it impossible to believe that the bursts were located in the distant universe, which would have to be the case if they weren't associated with our own galaxy. To be located so far away the gamma-ray bursts would have to be the most energetic events ever detected, a billion billion times more luminous than the sun--which seemed absurd.

Nonetheless, some astronomers held out for this far-out explanation. And as evidence from sophisticated new instruments came in, they appeared to be correct.

Which left the baffling problems of what could be producing such a titanic flood of energy, whether anything similar could happen in our galaxy, and what would be the unfortunate fate of life on Earth if it did.

Executive Producer: Paula S. Apsell
Produced for NOVA by Susan Kopman Lewis
Produced for Channel 4 by David Sington
Dox Productions for NOVA/WGBH and Channel 4

Now in its twenty-ninth season, NOVA is produced for PBS by the WGBH Science Unit. The director of the WGBH Science Unit and executive producer of NOVA is Paula S. Apsell.

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