Monday, October 23, 2006

Cosmic Bummer

"Cosmic Thoughts - Bummer Edition" by Greg Easterbrook

Keywords: supernova, creation, star, leviathon

Scripture: Job 41 (A supernova makes a good modern-day leviathon)

Recently, I was creeped out by this supernova. Detected Feb. 18 by Swift, a satellite launched to look for gamma-ray bursts, the exploding star already was the 24th supernova discovered at that early point in 2006. As instruments improve, exploding stars appear more common than cosmologists had expected, and that's not the best news we might have heard. Coded GRB 060218, this star detonation began as a gamma-ray burst that lasted 33 minutes -- absolutely stunning because previous gamma-ray bursts from space have lasted a few seconds at the most. The gamma rays came from 470 million light-years away. That was discomfiting because strong gamma-ray bursts usually emanate from what astronomers call the "deep field," billions of light-years distant and thus billions of years back in the past. A distance of 470 million light-years means the GRB 060218 supernova happened 470 million years ago. That is ancient by human reckoning, but many cosmologists had been assuming the kind of extremely massive detonations thought to cause strong gamma-ray busts occurred only in the misty eons immediately after the Big Bang. The working assumption was that since life appeared on Earth, there had been no stellar mega-explosion. Now we know there has.

For several days as the giant dying star GRB 060218 collapsed, this single supernova shined brighter than all 100 billion other suns in its galaxy combined. The detonation was so inexpressibly luminous that, though 470 million light-years distant, it could be seen by telescopes on Earth. And not just fancy telescopes at the tops of mountains: A few days after the Swift satellite detected the gamma-ray surge, an amateur astronomer in the Netherlands sighted the forming supernova through a backyard telescope. The stellar coordinates hit the Web -- it was at RA: 03:21:39.71 Dec: +16:52:02.6 -- and soon amateur astronomers the world over were marveling at the glistening beacon from the cosmic past. This explosion released so much energy that it happened 470 million years ago yet the light could travel for that protracted period, plus pass through the gas and dust of roughly a hundred galaxies along the way, and still illuminate mirrors of backyard telescopes on Earth.

Now here's what creeped me out: had GRB 060218 happened in our galaxy, life on Earth would have ended Feb. 18.

1 comment:

James said...

used 10/22/2006.