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How Neutron Stars Get Their Kicks
mustermark writes: "Now we may know why neutron stars zip through space at 1000 times the speed of a normal star. Massive stars have been shown to collapse aspherically, and chunks blown off in this process may recoil the neutron-star remnant in the opposite direction."
Holy moly, galactic billiards!
I'm going to have to get down to the Patent Office and get dibs on that... but first, Tau Ceti in the corner pocket.
I particularly enjoyed the dateline.
"Jun 19, 2000 - ROCHESTER, N.Y. -- When a massive star runs out of nuclear fuel something extraordinary happens in the space of a few seconds: The star's core collapses from a radius of 1,000 miles into a tight, dense ball."
Wow, all that happens here in Rochester?
Jeez. I really have to get over to the University of Rochester more often then!
|/usr/games/fortune
NightHawk
Tyranny =Gov. choosing how much power to give the People.
As the star collapses, if one side is less dense than the other gravity will cause the density gradient to increase. This insures that when it expels matter more matter is expelled on one side than the other. I guess it would be possible to have a star that's density is so balanced that no gravitational gradiant will be produced, but the odds of this happening is so insanely low that stars ALWAYS get a density gradient and therefore always get a kick when they are formed.
Understanding the mechanics of the universe is important because it increases our knowledge of science in general. It may not be clear right now how understanding something that happens thousands of light years away (and therefore took place thousands of years ago) may be useful. But one day it will be useful. After all at first studying the planets didn't seem that useful but Newton used planetary motion when he was fathering classical physics.
A closely matched binary system would trade accretion until the soon to be Neutron was orbiting a further away, but rapidly falling towards the slightly denser soon to be Nova. If the quasi Neutron star was far enough away when big brother lost his top, the shockwave, and infalling matter would actually push it to "ludicrous speed".
If the quasi neutron star was too close... well, it would still move (if not destroyed) but its chances of growing into an adult Neutron.
Any Accretion pulled off of the nova'd star would be stripped while moving, and the star would begin it's decay into a Neutron.
krystal_blade
It will be easy to motivate our fellow man; there is hardly anything people treasure more than not being annihilated.
Yeah, and the Earth is flat! After all, if it were round we would fall off. Constellations do change though quite slowly (when compared to the length of human life.)
I've got an idea: here is a book -- read it!
Hydrogen atoms have 1 proton and 2 nuetrons.
Most hydrogen atoms have merely 1 proton and no neutrons. A small percentage has 1 proton and 1 neutron, and this is called deuterium. An even rarer (the rarest) configuration is 1 proton and 2 neutrons, this is called tritium and is radioactive.
So, with Cosmic Inflation, coupled with moderate interest levels, people are gonna start lookin for other means of entertainment. (Do you know how much it costs to get a supernova light show?) Plus, there's always the tickets to those special event horizons, that everyone seems so hyped up on. And lets not forget that since the discovery of the Cosmic Background Radiation, everyone wants a microwave.
Everyone's gotta PAY for that stuff, and some people are being super dense, and writing rubber checks their atomic structure can't cash. Eventually, all those star banks get pissed, and they send in Guido, the Neutron Star to clear things up. He's got the gravity for Repo jobs, and the speed to get things done quickly... He probably carries around one of those Accretion(tm) golf clubs too, just in case.
There's just no getting around the speed this guy needs to get his job done, since nothing travels faster than a bounced check. And you think those black holes got any money? Hell no... They sucked down both theirs, and a whole lotta other paychecks during "binge week". Give em Guido Neutrono... He'll bust their kneecaps.
krystal_blade
It will be easy to motivate our fellow man; there is hardly anything people treasure more than not being annihilated.
OK, this article left me with one question... If these neutron stars accelerate due to matter being blown off the star, and assuming that this matter being blow off is less than the mass of the star, the expelled matter would obtain an acceleration greater than the remainder of the star.
....Paul
So, if the neutron star is going so fast, how fast is the stuff it's blowing off going?
More importantly, where is it going?
Oops, that's two questions isn't it? DOH!!! Three!
F U NE X N M? Son: "Dad... How do you spell 'hourly'?" Dad: "0 * * * *"
Since there aren't really any signs in the Universe that say "I am perfectly stationary, measure from me"
Actually, there is a pretty good one - the microwave background radiation.
There is a nice picture here which shows the relative temperature of this radiation as seen from earth. It is clearly red-shifted in one direction and blue-shifted in the opposite direction, indicating that the earth is moving rapidly (600 km/s) in the direction of the blue-shift. Some of this velocity is our motion around the sun, some is the sun's motion in our galaxy, but most of the velocity is common to our entire local group of galaxies.
If we were "at rest" in the universe, the microwave background would be uniform in all directions [more precisely, the dipole component would be zero; quadrupole and higher terms would still be present]. However, distant stars and galaxies would still be moving away from us due to the expansion of the universe.
and chunks blown off in this process may recoil the neutron-star remnant in the opposite direction
this theory has more applications than simply explaining the motion of neutron stars. for instance, i've often wondered when i'm bent over the toilet bowl blowing chunks after a huge drinking session, why my head recoils in the opposite direction, and everything else seems to be moving 1000 times faster than i am. now i know thanks to this new theory.
This theory has been in place for a long time. It is a well known fact that neutron stars are often moving with high velocities. Many such objects have had their proper motions (angular velocities) measured. It is also known that supernova remnants (the guts of a star after it explodes at the end of its life) are not spherical. This is the topic of research that I work on. To answer a question above I have measured motions in supernova remnants that vary by over a factor of two. That is, one side may be moving at 5,000 km/s and the other may be moving at 2,000 km/s. One can also see much more rich structure in the kinematics of these complex objects. For instance, I have found material moving inwards! Now that certainly is not a spherical explosion!
Just thought some of you might like a more in-depth look at neutron stars. I've been doing some reading on neutron stars in the last few days, so I hunted around in my browser's history and found the two articles I had been reading.
The first one, by New Scientist, is a neat article on stars and their hunger for the planets around them.
The second one, by Scientific American, is a bit technical, but it describes how the X-ray emissions from neutron stars are being used to estimate their size.
--
Well, since Hitchhiker's Guide was first out in the late '70s to early '80s, I suspect it came before Dangermouse.
...phil
...phil
"For a list of the ways which technology has failed to improve our quality of life, press 3."
g_blow_chunks();
I'm not sure what the memory requirements for a neutron star are though - probably quite high.
--- Hot Shot City is particularly good.
What's really weird, though, is that the rocket would see your clock as running slow.
The Mongrel Dogs Who Teach
I wonder whether it would be possible to detect a neutron star that is moving toward our solar system at a speed of say 2000km/s and the spin of that star is parallel to our viewing point so that the ejection beams can not be detected (the pulse can not be detected), wouldn't it be neat if a neutron star passed by Earth and maybe even hit it, or any other planet, or even the Sun? I defenetely would love to see the special effects!
You can't handle the truth.
OTOH, we are talking about tiny, tiny asymmetries:
- A supernova relases 10^51 ergs in mass motion and optical display, 10^53 ergs if you count neutrino emission.
- A neutron star has a mass of ~1.4 times our Sun's mass: to make it travel at 700km/second takes only 10^49 ergs.
So you see, even the fastest neutron stars we know of (the Guitar nebula, for example, is created by a pulsar going ~1600km/sec) use only a tiny fraction of the energy of a supernova.And still, even that tiny fraction takes explaining - but if we buy into hypernovae that create Gamma Ray bursts, then this is a trivial problem.
Sigh - its annoying to reduce your thesis proposal to a trivial problem!
Learn more here...
"I will take the Ring," he said, "though I do not know the way."
I'm an astronomer, and one area I do research in is the asymmetries of SNe. Actually, some supernovae appear to have asymmetries on the order of 30%. This is inferred from polarization measurements that we've done. One of these days I'll write up a story about it for starstuff.org (I am actually the co-creator of the site, though I didn't write this neutron star article), but for now you can see the gory details at: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi bcode=1999astro.ph.12033W&db_key=PRE&hig h=3845e365b719527 You can also see signs of SN asymmetries in the fact that man SN remnants aren't round. We've even been able to watch the evolution of the layers blown off of the closest supernova in a long time, SN 1987A. Check out: http://oposite.stsci.edu/pubinfo/PR/97/03.html Hope this clears up that comment.