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A Supernova In Red/Blue Plaid, Please
Snotnose writes "The New York Times is reporting that scientists have found a a supernova factory . From the article, scientists estimated that the cluster alone, which contains up to a million stars, probably produces a supernova once every two years. That is a rate 50 times higher than usual in entire galaxies. Stars explode in Earth's home galaxy, the Milky Way, only once in a century.. Sounds pretty awesome.
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For those of you who dislike the New York Times subscription requirement, here is a link to a google news search of related articles.
This was covered two days ago by space.com. They have pictures and good for people who didn't register on NYT.
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This page explains the link between Black holes & Supernovas...
When stars of very large mass explode in a supernova, they leave behind a core which is so massive (greater than about 3 solar masses) that it cannot be stabilized against gravitational collapse by an known means, not even neutron degeneracy. Such a core is detined to collapse indefinitely until it forms a black hole, and object so dense that nothing can escape its gravitational pull, ot even light.
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Other sites have pictures as well as not needing registration.
NY Times access without having to register:
Username: slashdot.com
Password: slashdot.com
Hopefully that will work for a whole mass of people logging in. Easy to remember. Take that, NYT >:) Pass it along.
Actually, when the gas goes by the pressure goes from zero to something less than zero.
is flat-out wrong. Negative pressures do show up in certain exotic bits of physics, yes, but the interstellar medium isn't one of them.
It's only an approximation to say that the pressure in space is zero. Very, very low, sure, but pressure will be some small positive number anywhere there exists an appreciable amount of gas (which is pretty much everywhere, actually). The pressure in the local ISM is something like 10e-19 bars, give or take a bit. As far as human hearing goes, that's certainly low enough to be effectively zero, but pressure waves can and do still exist, at positive but low pressures, albeit at frequencies and volumes far far below anything we could detect by ear.
In fact, it's very useful to think of the intersteller medium as a sort of atmosphere surrounding the galaxy, complete with high and low pressure zones resulting from differential heating, winds and superwinds blowing between those regions, "weather" of a sort along the boundaries between regions of different temperatures, and so on. For more detail (a *lot* more detail) check out Spitzer's Physical Processes in the Interstellar Medium or Osterbrock's Astrophysics of Gaseous Nebulae and Active Galactic Nuclei, hopefully available at your local university library.