Geek Trivia: More super than super

by Jay Garmon | Sep 20, 2005 7:00:00 AM

Tags: Jay Garmon, gamma ray burst, Geek Trivia Newsletter

Takeaway: What special breed of supernovae do astrophysicists consider to be a likely source for unexplained gamma ray bursts?

In pop astronomy circles�yes, such things do exist�the ostensible standard-bearer for high-energy phenomena is the supernova, a massive stellar explosion that effectively destroys entire stars. Supernovae garner a lot of well-deserved hype because they're not only among the most luminous events known to humankind, but they're also the "engines" that create nearly all of the complex elements found in the universe (read: anything with an atomic number higher than eight, as in oxygen). That's not too bad for an also-ran.

While supernovae certainly put out astronomical (pun intended) levels of energy, they pale in comparison to the most luminous and energetic phenomena known to science: gamma ray bursts (GRBs). GRBs are several thousand times more luminous and energetic than supernovae.

Gamma rays are the highest energy form of radiation�effectively, the "brightest" kind of light in the sky. So it's not surprising that a cosmic-level burst of gamma rays would rate higher on the astronomic "wow" scale than even a supernova.

What is surprising about GRBs is that they're an almost daily event�researchers observe at least 300 or so GRBs in any given year. Yet science has no clear idea where they come from.

That's like having a full-scale fireworks show above your house everyday but not knowing who's launching those skyrockets. The GRBs literally appear in the sky at random, lighting off massive displays of energy that last mere seconds�with effects that dissipate completely in hours.

In many ways, GRBs are among the most compelling mysteries confronting astrophysics. They are also among the most frustrating.

GRBs are virtually invisible to earthbound instrumentation. That's because the earth's atmosphere screens out most gamma rays (lucky for us, too).

Scientists didn't even know GRBs existed until the late 1960s, when the United States launched the Vela satellite project to search for clandestine nuclear testing on Earth. What the Vela satellites picked up were massive, random, unexplained bursts of gamma rays that astronomers eventually realized were coming from deep space.

In the decades since, astrophysicists have tried to determine the origin of GRBs, and a compelling candidate is a special breed of�you guessed it�supernovae.

WHAT SPECIAL BREED OF SUPERNOVAE DO ASTROPHYSICISTS CONSIDER TO BE A LIKELY SOURCE FOR UNEXPLAINED GAMMA RAY BURSTS?

What special breed of supernovae do astrophysicists consider to be a likely source for gamma ray bursts (GRBs), the most luminous cosmic event known to science whose origins have eluded astrophysicists for nearly four decades?

What do you call a really, really powerful supernova? A hypernova, of course. What differentiates a hypernova from a mere supernova is both the size of the star that's blowing up and the type of celestial object the remains of the star become.

In the case of a hypernova, a giant star collapses directly into a black hole�do not pass Go, do not collect $200. During this cosmic squeeze play, the collapsing star spews out jets of highly energetic plasma from each of its poles. These plasma jets contain staggering amounts of gamma rays, and that's what makes hypernovae a compelling candidate for the source of GRBs.

Of course, as usual, there's a caveat. Giant stars are statistically rare, and giant stars that collapse directly into black holes are rarer still, but GRBs are eerily commonplace. Thus, either hypernovae are not the sole source of GRBs, or scientists have greatly underestimated the frequency of black hole formation.

On the subject of GRB commonality�you know you're in Geek Territory when you read a sentence like that�it's safe to say that the Milky Way has not hosted a GRB in quite a long time. Be thankful: The level of lethal gamma rays emitted by a "local" GRB�say, any burst occurring within the more than 100,000 light-year diameter of our galaxy�would probably be enough to poison every living thing on earth. (And before you ask, yes, scientists have theorized a localized GRB as a potential cause of the extinction of the dinosaurs.)

The good news is that the Milky Way is unlikely to see any native GRB anytime soon, as GRBs appear to be native to distant star-forming regions at the edge of the universe. Perhaps GRBs and the hypernovae that might cause them are merely a symptom of galactic adolescence, the growing pains of a young galaxy that the venerable Milky Way has long since outgrown. If so, we may be so fortunate as to never experience a GRB up close and personal�except, of course, in the mysterious realms of Geek Trivia.

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The Trivia Geek, also known as Jay Garmon, is a former advertising copywriter and Web developer who's duped TechRepublic into underwriting his affinity for movies, sci-fi, comic books, technology, and all things geekish or subcultural.

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