Thursday, April 03, 2008

Explosion of Unimaginable Intensity Rocks Middle-Universe


NASA's Swift satellite recently detected the most violent explosion since the Big Bang. At least, the most violent explosion that we know of. The event came in the form of a gamma ray burst originating 7.5 billion light years away (that's half-way across the known universe).

Yes, that means this explosion occurred long before the earth was created (it took 7.5 billion years for the light from the explosion to reach us), and about half way between now and the time the universe was born.

The burst was so extreme that it could be seen with the naked eye. To date, it's the furthest object (or event) ever visible to the naked eye. Now get this. The next closest object, visible to the naked eye in the night sky, is the Great Andromeda Galaxy, according to Sky and Telescope. Incredibly, Andromeda is just 2.9 million light years away. So imagine the earth is on the goal-line of a football field. If the gamma ray mega-burst occurred on the other goal line, the Andromeda galaxy would be just one-inch down the field. That's right. Normally, we can only see objects one-inch in front of our noses. But this burst comes along, and it's visible from 100 yards away. Amazing.

When NASA scientist Dr. Stephen Holland first heard of the Swift satellite's tremendous detection, he thought, "either we've got the burst of the century, or something went wrong." Holland was
interviewed on Quirks and Quarks, the Canadian Broadcasting Company's weekly science show.

On the program we learned this explosion was 10-times more intense than the brightest gamma ray burst previously detected, but lasted only one minute (some bursts can last up to 20 minutes).

Holland told Quirks the energy in this burst is equivalent to 2.5 million supernova going off at once.

What caused the explosion? Most likely, the birth of a black hole. Gamma ray bursts either occur when a black hole is originally created (when a star runs out of fuel and implodes on itself), or when two neutron stars collide. In the case of this recent, mega-burst, it was too big for a neutron star collision.

The star which collapsed, creating the black hole that sparked the burst, was probably 40-times the size of our own sun, explained Holland.

Another incredible aspect of this story is the fact that we even detected this burst. The Swift Observatory can only cover one-sixth of the night sky at a time. So we happened to be lucky the Observatory was pointed in the right direction. Also, when gamma ray bursts are shed by black holes, they shoot in one direction, like a "turbocharged cosmic blowtorch,"
described the official NASA press release. So not only did we happen to be looking in the right fraction of space at the right time, but it just so happened that this burst was pointed directly at us.

The chances of detecting this event seem so slim, I wonder what other spectacular events we're missing every day of the year.
[The picture in this post shows the gamma ray burst through Swift's X-ray telescope (left) and the other shows the optical telescope's view.]
(Photo Courtesy NASA)

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.