Geek Trivia: First to the Fourth

What artifact suggests that native Americans may have documented the appearance of a July 4th supernova--in the 11th Century!

OK, so we didn't send out a Geek Trivia newsletter, as TechRepublic shut down in observance of the U.S. Independence Day holiday. Never fear, GT-addicts, as the ol' Trivia Geek has your back with this this Classic Geek, which originally ran July 5, 2006.

Every year, the United States celebrates its collective birthday -- July 4th -- in the usual fashion: Detonating enough fireworks to shoot down a small national air force. But once this annual episode of pyromaniacal patriotism is behind us, we Yankees can take a more objective look at the other famous set of sky-lighting fireworks that have occurred on this date: The Crab Nebula.

On July 4, 1054, Chinese astronomers observed the appearance of a "guest star" in the constellation of Taurus. Arab observatories noted a similar phenomenon, though there are no records of European scholars noticing the celestial event. That's more than a little surprising, since the "guest star" was bright enough to appear in broad daylight for three and a half weeks and provided enough light to read by at night.

What Europe failed to remark upon was a good old-fashioned supernova. A star about eight to 12 times the mass of our sun, situated about 6,300 light years from Earth, exhausted its nuclear fuel and collapsed in on itself.

In the crush of the implosion, the remaining stellar mass heated to the point of a massive explosion 10 billion times as bright as our own sun. If the same star had exploded the same way a mere 50 light years from Earth, it could have extinguished all life on the planet.

As it was, the supernova occurred in precisely the right place at precisely the right time for several human cultures to observe it. The distance was safely away from Earth such that the light reached us when relatively sophisticated star-watching societies had appeared in history.

This particular supernova also had some get-noticed advantages because it left behind two significant bits of fallout: The Crab Nebula and a pulsar. The nebula is not only ever-expanding and changing shape, but the clockwork electromagnetic emissions of the pulsar visibly illuminate it, effectively creating an unmissable astronomic eye-grabber.

Though the nebula was only visible to the naked eye until 1056, its two-year exhibition in the night sky was the ultimate example of naturally occurring Fourth of July fireworks. Somewhat appropriately, there's even evidence that Native Americans might have caught this foreshadowing event -- and recorded that first July 4th display in an ancient artifact.


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