Sunday, February 26, 2006

Supernova coming?

squeeze the star until the gamma-juice comes out the ends

A unique celestial explosion was observed by the new Swift satellite, unusual in both length (33 minutes) and spectra. The unusual explosion may be the beginning of a star collapse, which could mean that a supernova is happening "right now"(*). The supernova would reach peak brightness in a week. The last supernova visible to the naked eye during daytime appeared in 1604. The last one visible to the naked eye at night was seen in 1987.

NASA has a nifty mpeg showing how the star-collapse model would lead to gamma-ray jets, which is what we might or might not be observing. Newsweek has the short "scientists are baffled" wire copy article here. NASA has some good educational material on supernovas online, as does space.com in the equally brief article on this news.

Needless to say, that area of the sky is being closely observed.

(*) This is the definition of "right now" that actually means 440 million years ago, since that's how many light-years away the explosion was. Note also that this means the star is relatively "close", since it could be as far as ~14 billion light years away, the current estimated size of the universe.

This science stuff is kooky. Update: so much so that my brother straightened me out on the dates. I have edited the post accordingly, lest any other astronomy-minded folk come here and do spit-takes all over their keyboards. His comment also has some great quotes on the mind-bending magnitude of supernova.


(Image from NASA's MPEG.)

1 Comments:

Anonymous Alan said...

Travis, you should edit this sentence."The supernova would reach visible peak brightness in a week. If this interpretation is true, this is news because the last supernova was in 1604." Did you mean supernovae that are naked eye visible, at night? Daytime visible? Those are extremely rare. But I am pretty sure this one will not be naked eye visible, though I would have to do more digging than the short articles.

Supernova happen all the time, and the last naked-eye-visible one was in 1987."Next to the possible Big Bang of an initial Creation, Stirling believes that there is nothing to touch a supernova explosion, even if there are so many scattered throughout the Universe that there is about one such explosion every second."

"At 07:35 UT on 23 February 1987, one of the components of a magnitude 12 star in the constellation Doradus, catalogued as Sanduleak -69d 202, in the Large Magellanic Cloud (LMC) at position RA 05h 35.1, dec -69d 16' 50", erupted to produce Supernova 1987A. The supernova was widely visible from the southern hemisphere and was the first supernova to be visible to the naked eye since those observed by Johannes Kepler in 1604 and Tycho Brahe in 1572."

I also like this sentence from the link:"Horizon quoted the energy involved in the collapse of the star that formed the Crab Nebula to be about 1E46 J (1E53 ergs) or the equivalent of the energy dissipation of the whole Universe (as far as we know it) for one second."

The whole freaking Universe? Hard to grasp that one solar system could produce that much energy, even if only briefly.
All quotes from:
http://www.ast.cam.ac.uk/~ipswich/Miscellaneous/SN1987.htm

Monday, 27 February, 2006  

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