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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.
Please direct all bug reports to
the supermassive blackholes found near the centers of some (most?) galaxies are not (as far as we /know/) formed from a supernova explosion.
If I recall correctly...
Mmmm......sacrelicious.
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.
/sig
Other sites have pictures as well as not needing registration.
It's simple. Just replace the "www" in the url with "archive" and you'll never need to register. Of course, you'll have to find the article when you get there.
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.
The book describes a species of aliens who see in many more colors than we do. One color, commonly found in sunsets, is translated into English as "plaid."
If you haven't read it already, I highly recommend it. It's arguably the best book by one of the brightest authors out there. He's the only author where I can't find anything to quibble about concerning his computer science. [Sample Chapter]
The universe did not have a "source point" where all matter spewed from in the big bang. Instead, its space itself that expands and carries everything along with it in more or less an even pace.
Use a balloon as an analogy. Take a balloon before blowing it up and use a felt-tip marker to put lots of dots on it. The dots represent galaxies and the balloon the fabric of space. Now blow up the balloon. All the dots recede from each other evenly, even though there is no source point. While you may think of the center of the balloon as a source point, it isn't really, because it exists outside the normal 2 dimensions of the surface of the balloon.
Increase all the dimensions by 1 and you have the situation you do in the universe. Space itself is expanding. Thus since everything has not been thrown out from a source point, there is plenty of time for gravity to pull together galaxies over great distances. Gravity is the weakest of the four fundamental forces but its effect stretches over the longest distance.
Also, when galaxies collide, in most cases there is very little star-to-star collisions, since there is so much empty space between the individual stars. What happens is the interplay of gravity between the stars warps the overall structure of the galaxy, which can have the effect of either stripping it of starmaking material and thus lead to the slow death of the galaxy, or concentrating it and leading to bursts of stellar births (and deaths, if the generated stars are very high mass and burn throught their hydrogen quickly).
Hope this helps a little.
Karma: Frotzed (mostly due to the Frobozz Magic Karma Company)
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.
Sorry. I meant more than zero. I'm not sure how "less" got in there. I think that I was originally going to say "vacuum goes from perfect to less than perfect" but then I realized space wasn't a perfect vacuum, and changed to pressure from vacuum but didn't change the "less" to "more".
Now I hope hope I make more silly mistakes like that.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
As usual, the Astronomy Picture Of the Day has a very nice picture and explination of this.
And as a bonus, today's APOD is one of the kewlest sunset pictures I've ever seen.
M@
Krispy Cream is people