Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS

NOVA Online (see text links below)
Death Star  
Did you know that...
  • gamma-ray bursts are the most spectacular celestial fireworks since the big bang.

  • within seconds or minutes, they may emit more energy than our sun will release during its entire 10 billion years of life. (1)

  • the explosions that give rise to gamma-ray bursts eject debris at nearly the speed of light (186,000 miles per second).

  • it has taken about 12 billion years for the gamma rays from one recently detected burst to reach us. (2)

  • even though they occur billions of light-years away, some gamma-ray bursts are so powerful that they can affect electronics in spacecraft. (3)

  • if a large gamma-ray burst occurred within about 3,000 light-years of us, it would be catastrophic to life on Earth. (4)

  • our sky is hit with gamma rays from a distant burst roughly three times every day. (5)

  • more energetic and penetrating than X-rays, gamma rays can pierce half an inch of lead.

  • gamma rays are photons, just like the ones we see as optical light, but about a million times more energetic. (6)

  • most of a burst's energy comes in the form of radiation of between 100,000 and 1 million electron volts (the photons of optical light, by contrast, have energies of a few electron volts). (7)

  • if a particularly powerful gamma-ray burst radiated its energy as visible light, that burst would appear to us brighter than any star, as bright as Venus or Jupiter. (8)

  • even though it was 10 billion light-years away, a gamma-ray burst detected on January 23, 1999 bore an optical flash so bright that it could have been seen with a pair of binoculars. (9)

  • if that burst had occurred in the Milky Way galaxy, it would have shone as bright as our sun at midday. (10)

  • gamma-ray bursts can last from about 30 milliseconds to over an hour. (11)

  • astronomers have located gamma-ray bursts in regions of very dense gas where new stars are born. (12)

  • many theorists today believe that gamma-ray bursts may be associated with a violent death of massive stars, i.e., powerful supernova explosions.

  • gamma-ray bursts, which may have arisen when some of the first stars that formed following the big bang died, may hold clues to the earliest universe.

  • they were only detected, by chance, in the late 1960s, when U.S. military satellites monitoring our planet for gamma rays from nuclear weapons tests detected an entirely new source of gamma rays coming from deep space. (13)

  • by 1998, 25 years after publication of the scientific paper that announced the discovery of gamma-ray bursts, more than 3,000 scientific papers had been written about the phenomenon. (14)

  • yet where they originate, and why they have such truly astronomical energies, continues to stump astronomers. (15)



Sources

Note: Unless otherwise specified, all sources are NOVA/WGBH.
  1. Gerald J. Fishman and Dieter H. Hartmann. 1999. "Gamma-Ray Bursts: New Observations Illuminate the Most Powerful Explosions in the Universe." In The Scientific American Book of Astronomy, edited by the editors of Scientific American. New York: The Lyons Press, p. 21.
  2. from "Hypernova," a BBC Horizon program, original airdate 10/18/01.
  3. Bohdan Paczynski. 2001. "Gamma-Ray Bursts—The Most Spectacular Fireworks." In Our Universe: The Thrill of Extragalactic Exploration, As Told by Leading Experts, ed. S. Alan Stern (Cambridge University Press, 2001), p. 90.
  4. Peter J. T. Leonard and Jerry T. Bonnell. 1998. "Gamma-Ray Bursts of Doom." Scientific American, February 1998.
  5. Fishman and Hartmann, p. 21.
  6. Paczynski, p. 90.
  7. Fishman and Hartmann, p. 24.
  8. Paczynski, p. 90.
  9. Ibid., pp. 103-104.
  10. Ibid., p. 105.
  11. Fishman and Hartmann, p. 24.
  12. "Gamma-Ray Bursts May Originate in Star-Forming Regions." NASA News Release, 4/4/01.
  13. Paczynski, p. 89.
  14. Fishman and Hartmann, p. 26.
  15. Ibid., p. 21


Printer-Friendly Format   Feedback

One Astronomer's Universe | A Bad Day in the Milky Way
Catalogue of the Cosmos | Tour the Spectrum
Resources | Transcript | Site Map | Death Star Home

Search | Site Map | Previously Featured | Schedule | Feedback | Teachers | Shop
Join Us/E-Mail | About NOVA | Editor's Picks | Watch NOVAs online | To print
PBS Online | NOVA Online | WGBH

© | Updated January 2002
 

Support provided by

For new content
visit the redesigned
NOVA site

Shop Teachers Feedback Schedule Previously Featured Site Map Search NOVA Home Death Star Home Site Map Death Star Home