Posted on 02/18/2010 2:50:35 PM PST by NormsRevenge
CHICAGO (AFP) – Astronomers who have long used supernovas as cosmic mile markers to help measure the expansion of the universe now have an answer to the nagging question of what sparks the massive stellar explosions.
"These are such critical objects in understanding the universe," lead author Marat Gilfanov of the Max Planck Institute for Astrophysics in Germany said Wednesday in describing his team's study.
"It was a major embarrassment that we did not know how they worked. Now we are beginning to understand what lights the fuse of these explosions."
Most scientists say Type 1a supernovae are formed when a white dwarf star -- the collapsed remnant of an old star -- becomes unstable after it exceeds its weight limit.
Instability could come from the merging of two white dwarfs or accretion -- a process in which the gravity of the star draws in enough material from a sun-like companion.
Using NASA's Chandra X-ray Observatory, Gilfanov and his team studied the supernovas in five nearby elliptical galaxies and the central region of the Andromeda galaxy.
"Our results suggest the supernovae in the galaxies we studied almost all come from two white dwarfs merging," said co-author Akos Bogdan, also of Max Planck.
"If the supernova were produced by accretion, the galaxies would be roughly 50 times brighter in x-rays than actually observed."
Further study will be needed to determine if merging is also the primary cause of supernovae in spiral galaxies.
(Excerpt) Read more at news.yahoo.com ...
A NASA image of the debris of an exploded star, known as supernova taken from
NASA's Chandra X-Ray Observatory. Astronomers who have long used supernovas as cosmic mile markers
to help measure the expansion of the universe now have an answer to the nagging question
of what sparks the massive stellar explosions. (AFP/NASA/File)
Chandra X-ray Center, Operated for NASA by
the Smithsonian Astrophysical Observatory
This site was developed with funding from NASA under contract NAS8-03060.
http://chandra.harvard.edu/
M31:
NASA’s Chandra Reveals Origin of Key Cosmic Explosions
http://chandra.harvard.edu/photo/2010/type1a/
Blaming cataclysmic events in this way is racist and height-insensitive....
Our whole universe was in a hot dense state,
Then nearly fourteen billion years ago expansion started. Wait...
The Earth began to cool,
The autotrophs began to drool,
Neanderthals developed tools,
We built a wall (we built the pyramids),
Math, science, history, unraveling the mysteries,
That all started with the big bang!
I thought they were caused by global warming, but maybe I’m confusing them with black holes.
Well, that sounds better than describing the event as “2 albino midgets” merging, LOL.
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This is just more proof that SUV’s are killing the polar bears.
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