How a Pulsar Gets Its Spin

brian0918 writes "Until now, the assumption has been that the rapid spin of a pulsar comes from the spin of the original star. The problem was that this only explained the fastest observed pulsars. Now, researchers at Oak Ridge have shown that the spin of a pulsar is determined by the shock wave created when the star's massive iron core collapses. From the article: 'That shock wave is inherently unstable, and eventually becomes cigar-shaped instead of spherical. The instability creates two rotating flows — one in one direction directly below the shock wave and another, inner flow, that travels in the opposite direction and spins up the core. The asymmetrical flows establish a 'sloshing' motion that accounts for the pulsars' observed spin velocities from once every 15 to 300 milliseconds.'"

Comments

Pulsar gets it's spin

[DittoBox]

For each and shock that waves
Another Pulsar gets it's spin
So show you care and let your iron core collapse
And help a pulsar spin tonight...

a-z

[Anonymous Coward]

Mumble mumble... angular momentum...
Therefore, God exists.

Not trying to discredit....

[Anonymous Coward]

But it seems that most of these science articles, particularly the ones related to astronomy, have forgotten the word "theory".

Re:Not trying to discredit....

[Anonymous Coward]

Its theory only if you can you prove that NASA has not created a pulsar somewhere in a far far away galaxy.

*Yessss, nailed it!*

Re:Not trying to discredit....

[servognome]

But it seems that most of these science articles, particularly the ones related to astronomy, have forgotten the word "theory".

All science is theory, so it would be redundant.

Re:Not trying to discredit....

[fbjon]

It's an explanation that fits observations, and now we can read about this new development. What's the problem? That nobody made any predictions yet?

Bad reporting

[exp(pi*sqrt(163))]

From 'the first plausible explanation' to 'researchers at Oak Ridge have shown that the spin of a pulsar is determined by the shock wave created when the star's massive iron core collapses'. Shows how poor journalists give scientists a bad name by making their claims seem much stronger than they are. The press release is very careful in how it makes its statements. The /. story isn't.

Re:Bad reporting

[jdigriz]

Bah, unstable shockwave giving a pulsar its spin! Ridiculous! Pulsars obviously spin through Intelligent Exploding!

Re:Bad reporting

[Surt]

Bah, unstable shockwave giving a pulsar its spin! Ridiculous! Pulsars obviously spin through Intelligent Exploding!

The sad thing about this argument is that it's clear in the original Aramaic that they meant Imploding.

Re:Bad reporting

[njh]

Perhaps the 10 well written stories were all passed over?

Re:Bad reporting

[Hal_Porter]

The sad thing about this argument is that it's clear in the original Aramaic that they meant Imploding.

God spoke the Queen's English, not some obscure semitic language.

Pulsars as GPS

[mrcaseyj]

The most interesting application of pulsars I've heard of is using them like GPS transmitters. Since pulsars are about the most precise timing devices known, if you time the arrival of the pulse from at least four of them you can use the time differences to triangulate your position precisely anywhere in the solar system.

Re:Pulsars as GPS

[ArcherB]

The most interesting application of pulsars I've heard of is using them like GPS transmitters. Since pulsars are about the most precise timing devices known, if you time the arrival of the pulse from at least four of them you can use the time differences to triangulate your position precisely anywhere in the solar system.

You'd need a GPS device that could detect the pulses from at least two pulsars from anywhere on earth. Now if you were to create a UPS (Unversal Positioning System) device that would work outside Terran interference, you'd have something!

Re:Pulsars as GPS

[swebster]

This idea was used on the Pioneer plaque (http://en.wikipedia.org/wiki/Pioneer_plaque).

Re:Pulsars as GPS

[Anonymous Coward]

WTF? So what you are saying is that now we need pulsars in our solar system so that you can get higher precision of your 50$ GPS devices?

Re:Pulsars as GPS

[mrcaseyj]

I think the idea of Pulsar GPS is primarily intended for interplanetary spacecraft. For terrestrial stuff GPS probably works better. One problem with Pulsars is that you would have to know which pulse to measure the time difference relative to the other Pulsars. if a pulsar pulses every 300ms then the pulses will be about a third of a light second apart or about 100km. If you go 100km relative to the pulsar you might get mixed up as to which pulse to lock onto and think you hadn't moved. The problem gets worse as the pulse rate gets higher. GPS doesn't have this problem because the absolute time is encoded within the signal from each satellite so you know the date and time each pulse left the GPS satellite.

One way to deal with the problem is to carefully keep continuous track of your position so you can keep straight which pulse to measure. If you can figure out where you are accurately enough by some other means you can figure out which pulse to measure. You can decrease the uncertainty of which pulse to use by using more than four pulsars. For example if one pulsar pulses every 7ms and another pulses every 11ms you can increase your window to 77ms by watching as they go into and out of sync.

I'm guessing that another problem is that the pulsars probably have a rather faint signal. You may have to have four or more large high gain dish antennas pointed in different directions to pick up the signals. This would be impractical on earth for most applications and would be a lot of extra weight for a spacecraft also. You might be able to have just one dish and point it at each pulsar in turn.

I don't see anything about this on Wikipedia. I think I'll add it one of these days.

Re:Pulsars as GPS

[mrcaseyj]

:)

Great idea, we could get a much stronger signal if we went to get some pulsars and brought them back to our solar system. The only question is should the expenditure be budgeted for fiscal year 2008 or 200008?

Re:Pulsars as GPS

[suitepotato]

Keeping exact track is not always necessary as each and every star, pulsar, etc. which emits radiation is not exactly the same as any other. With advances in sensor technology and computational abilities it is likely we will be able to know what a given pulsar by name/designation puts out, look for signatures of the closest ones and identify against the catalog, then relate their positions as seen from Earth at the time of cataloging versus what we see now, etc...

Of course we can do this with stars as well.

Keep it on the ship? Probably not. We'd probably seed our home system with science and navigation stations manned and unmanned by the hundreds and have them broadcasting coded signals on specific intervals along with any and all needed navigational data instead. Interstellar travel is we ever make warp drive work, yeah, then we need it. Until we establish a network in the next system we achieve foothold in.

Re:Pulsars as GPS

[Anonymous Coward]

if a pulsar pulses every 300ms then the pulses will be about a third of a light second apart or about 100km. If you go 100km relative to the pulsar you might get mixed up as to which pulse to lock onto and think you hadn't moved.

Except that a light second is not 300km but 300.000km, so you would have to be moving really fast to encounter this problem.

Re:Pulsars as GPS

[iluvcapra]

a third of a light second apart or about 100km

I think you mean 100,000 km.

If you go 100km relative to the pulsar you might get mixed up as to which pulse to lock onto and think you hadn't moved.

You wouldn't use the phase of the pulsar signal to get a distance reading, but you could use it's frequency as a way of identifying it uniquely, and then you would triangulate your position by getting a bearing on three or four pulsars; this is essentially how the starburst pattern on the Mariner Plaque is supposed to work for aliens trying to find Earth. It gives the frequency of pulsars near the earth and their bearing to Sol relative to the galactic center. The aliens would identify the pulsars by their frequency, and then use their knowledge of the pulsars' absolute locations to work backward and triangulate the position of Sol (assuming these aliens, a million years from now, are able to backtrack the locations of all the pulsars, as they will all have moved relative to Sol and will have slowed down in their spinning, causing an error in our reported frequencies).

Re:Pulsars as GPS

[vmcto]

umm... p

Plus there's that whole problem of the planet moving through space...

Re:Pulsars as GPS

[mrcaseyj]

a third of a light second apart or about 100km I think you mean 100,000 km

Oops.

Ah, whats a few zeros here and there? :)

I was writing in a hurry and the value wasn't very important anyway.

You wouldn't use the phase of the pulsar signal to get a distance reading, but you could use it's frequency as a way of identifying it uniquely, and then you would triangulate your position by getting a bearing on three or four pulsars; this is essentially how the starburst pattern on the Mariner Plaque is supposed to work for aliens trying to find Earth. It gives the frequency of pulsars near the earth and their bearing to Sol relative to the galactic center. The aliens would identify the pulsars by their frequency, and then use their knowledge of the pulsars' absolute locations to work backward and triangulate the position of Sol (assuming these aliens, a million years from now, are able to backtrack the locations of all the pulsars, as they will all have moved relative to Sol and will have slowed down in their spinning, causing an error in our reported frequencies). Interesting point. The pulsars will move and slow down by the time Mariner gets anywhere (or is it Pioneer or Voyager).

However pulsar GPS and the Pioneer plaque are both interesting and clever tricks with pulsars, but the two methods have a totally different purpose and procedure. The Pioneer plaque just uses the time between pulses to tell aliens which pulsar we are giving the distance to. It's just a way of telling one star from another. But pulsar GPS is for when you already know what pulsars you're looking at and where those pulsars are and you want to find your precise location in the solar system(or beyond).

With pulsar GPS you're using changes in the arrival times of the pulses to determine if you're getting closer to the pulsar or getting farther away. The problem is that unlike GPS there is nothing different about the pulses to tell one pulse from a particular pulsar from the next pulse from the same pulsar. Therefore if you measure your times relative to the wrong pulse you might think yourself hundreds of thousands of kilometers closer or farther from the pulsar than you actually are(or much more).

Re:Pulsars as GPS

[Lord Ender]

If every pulsar has a distinct period, how could you ever get confused which is which? Couldn't you always be able to determine this based on their periods? /forgive me if i'm missing something fundamental. it's fri night and i'm a bit lit

Re:Pulsars as GPS

[p_trekkie]

Allow me to clarify some things. I've done research in this area, and here is how a pulsar based interplanetary navigation would work.

First, it would not use radio pulsars, because it's ridiculous to have four high gain antennas on a space craft. Rather, it would use the x-ray portion of the spectrum. X-ray detectors don't even require optics. However, with a coded aperture mask and some software, the position of the source the pulse is coming from can be determined.

Second, you are on the right track with the knowing your existing position. Pulsar navigation can only work with differential positions. Essentially, it would provide a correction the existing intertial guidance systems. It has to be differential because we don't actually know the positions of the pulsars in 3-d space. With astronomical objects, we're lucky to get a position within a parsec, much less the centimeters we know GPS satellites to. Unfortunately, differential calculations get hideous because general relativity affects pulsar arrival times differently in different parts of the solar system.

This goes more to the parent post, but the accuracy of the system would be much better than the pulse period, because pulse arrivals, if integrated over time, can be timed to a microsecond or possibly better. It is predicted that the accuracy of the system would be on the order of a few hundred meters.

For more information see this fellow's doctoral dissertation on the subject.

Re:Pulsars as GPS

[LouisZepher]

Rather insightful idea, but if we're gonna have manned/unmanned beacons anyway, why not just use them to triangulate position?

Re:Pulsars as GPS

[John Hasler]

> Second, you are on the right track with the knowing your existing position.
> Pulsar navigation can only work with differential positions. Essentially, it
> would provide a correction the existing intertial guidance systems.

It would be closer to LORAN than to GPS.

Re:Pulsars as GPS

[lowen]

Being that we do pulsar research here at PARI, I'll comment on this timing thing. Some pulsars are quite regular; most however do have what are known as 'glitches' and in the case of the Crab pulsar 'giant pulses'; both of these phenomena are unpredictable and skew any timing you might receive from the pulsar. Also, pulsar timing requires some fairly extensive integration of the incoming pulses, as most pulsars miss 'beats' frequently, and pulses vary somewhat in terms of amplitude. Some pulsars exhibit odd phasing effects as well.

Also, pulses have to be dedispersed, which is somewhat complicated to do in real-time, especially in the ideal frequency range for observations (we observe in the 300-350MHz range, with our best sensistivity occurring in the 327 window); the larger the dispersion measure (DM) the more complicated dedispersion becomes. This dispersion makes the initial impulse signal become a chirp signal, and it needs to be 'dechirped'. This makes it difficult to find the instant of the pulse arrival, as it is 'smeared' not a hard edge.

Pulsars are almost uniformly weak sources; with our 26 meter (85 feet) dishes they are still a challenge to receive at 327MHz; and they get weaker as the frequency goes up. Although the difficulty of dedispersing the pulse becomes easier as frequency rises.

We use several pieces of equipment to receive pulsars: RFspace's SDR14 with gating modification is one, and the GNUradio project's USRP is another. We have a specialized receiver that uses analog filter banks to do the dedispersion, but it is not currently in operation.

The most accurate timing soures commercially available that I know of are hydrogen masers; the timing from them easily exceeds the accuracy of pulsar timing. Cesium and Rubidium, along with ovenized quartz, are increasingly inaccurate, but if a pulsar can be accurately timed and the timing fluctuations of the pulsar measured by a source as inaccurate as a Rubidium standard, then the Rubidium standard is more accurate than the pulsar as to timing. That is, in order of accuracy: hydrogen>cesium>rubidium>oven-quartz; the pulsar accuracy is typically between the quartz and the rubidium.

If you are looking for position information (as Global Positioning System implies) triangulation upon several sources (you mentioned four) in the sky is doable; however, at radio frequencies these are not point sources; at 327MHz, for instance, an 85 foot parabolic dish has a 3dB beamwidth of about 2.4 degrees of arc; this is too wide to use for accurate positioning. The common and bright 1420 spectral sources are likewise gas clouds; much continuum radiation isn't from point sources. You will not be able to recieve pulsars with anything but a highly directional antenna; they are just too weak. Of course, in a spacecraft it is easy getting the cold temperatures to cool a low noise amplifier down to get the noise figure where you need it to be; I would question if the Johnson noise in available LNA devices would be low enough even then to make receiving a pulsar (even the brightest) with an omnidirectional antenna possible.

Now, terrestrial observations of pulsars get doppler effects due to the earth's revolution around the sun (also due to rotation, but the diurnal doppler swamps out the daily doppler) that depend upon your location on the earth; to determine position from the observed pulsar's timing would require you to do the local standard of rest calculation backwards, yielding time and location from the variance in pulsar timing and sky location. While this might be possible if you have four pulsars being timed, it would be rather difficult. Timing a single pulsar will not help you, as that is insufficient information to solve for time and location by calculating the local standard of rest in reverse. (that is, you take the measured pulsar period of several (but not too many) pulses, integrate, compare to theoretical yielding the measured doppler, then reverse the doppler calculation ordinarily yielded by the L

Re:Pulsars as GPS

[Anonymous Coward]

Good! I've often thought we should sent a second probe out, to destroy the first one so they can't target their star-destroying beam accurately.

Or, a second probe to deface the first one, so when we later see a star being destroyed we know they "found" us, and can plan accordingly...

Re:Pulsars as GPS

[iluvcapra]

With pulsar GPS you're using changes in the arrival times of the pulses to determine if you're getting closer to the pulsar or getting farther away

Exactly. Pulsars are like VORs but without the magnetic-north synchronization signal. You can figure your velocity to or from by measuring the doppler, but you can't figure your bearing, and therefore, cannot figure your position.

By comparing the difference between your observation of a pulsars frequency and its frequency from a known reference, you can figure out your velocity to or from, but not your position. So first you need a very good reference datum, like from Earth, but even more, you need a very accurate clock on your ship so you can make good measurements of the pulsar's doppler. If you measure a few pulsars at once, you can build a resultant V from a collection of pulsars and work a solution for your V relative to your reference datum, like figuring your groundspeed in 3 dimensions, with wind in 4 dimensions. Fun fun fun.

This is good for speed, and figuring out your position this way is as easy as doing an integral of your V, but it's open-loop and little errors in your speed measurements will give you bad position fix, eventually. I was just thinking about this again today, and if you watched two pulsars at once, and measured the difference in phase between the two, given their frequency and position is known, you could plot your position along a hyperbola with the two pulsars as foci, just like LORAN. Getting a third reading would then give you a fix.

Pulsars are really a boon to celestial navigators, no doubt.

Just like pulsars...

[doit3d]

...I see ALOT of things spinning when I get sloshed.

wait a minute.

[User 956]

Now, researchers at Oak Ridge have shown that the spin of a pulsar is determined by the shock wave created when the star's massive iron core collapses. From the article: 'That shock wave is inherently unstable, and eventually becomes cigar-shaped instead of spherical. The instability creates two rotating flows -- one in one direction directly below the shock wave and another, inner flow, that travels in the opposite direction and spins up the core. The asymmetrical flows establish a 'sloshing' motion that accounts for the pulsars' observed spin velocities from once every 15 to 300 milliseconds.'

Hey now, it's not an asymmetrical flow that establishes an observed spin velocity. It's 'Intelligent Exploding'.

Re:wait a minute.

[Anonymous Coward]

01.20.09: Bush's Last Day [bushgoingawayparty.com].

That's going to be one heck of a party in zero locations ;)

now I can sleep...

[mtec]

..zzzzzzzz..

Strange summary...

[imsabbel]

The current theories also explain the slow pulsars.
By the simple way of energy loss.
Take the crab nebular pulsar as example. Currently spinning about 30 times per second, it will be down to 20 in a few thousand years. Those thing have huge magnetic fields, and they can couple out energy amounts into the planetary nebular even OB stars usually can only dream of.

So no, its not like everybody was totally stupid before this theory.

Re:Strange summary...

[Anonymous Coward]

From TFA:
"Previously, astronomers did not have a workable explanation for how the pulsar gets its spin. The assumption to this point has been that the spin of the leftover collapsed core comes from the spin of the original star. Being much smaller, the pulsar would then spin much faster than the original star, just as a figure skater spins faster by pulling his or her arms in.

"The problem with that approach is that it would explain only the fastest observed pulsars. The ORNL-NCSU team, on the other hand, predicts spin periods that are in the observed range between 15 and 300 milliseconds."

Re:Strange summary...

[Gospodin]

...even OB stars usually can only dream of.

Do pulsars dream of magnetic sheep?

Re:Strange summary...

[forand]

Of course people were/are not stupid. However your explanation is not correct, while you can measure the spin down rate of a pulsar and correlate it with its energy loss thus giving you a good idea how the spin down evolves with time, you can also measure WHEN the neutron star was created by observing the super nova remnant or looking in history to find some observation of the event, this gives you a starting date. Before this explanation you could not have spun down the neutron star in the alotted time via the observed rate.

Re:Strange summary...

[iamlucky13]

Thanks for explaining that.

However, the submission and the article are still a little strange in their word choices (mostly the submission...If you re-read the article a few times, it makes more sense). They seem to suggest that the assymetric shockwave gives the pulsars their sping, when according to the theory, it actually takes away spin. I clicked on the article wondering how in the world they were postulating massive, exploding objects with very low or possibly non-existant angular momentums.

If I'm reading it right, the ejected debris from the rebound should spiral more in this case to account for the net loss of angular momentum, no?

Anyway, the worst part was this line:

According to three-dimensional simulations they performed at the Leadership Computing Facility, located at ORNL, the spin of a pulsar is determined not by the spin of the original star, but by the shock wave created when the star's massive iron core collapses.

What they really meant is the original spin plus the shockwave, not just the latter instead of the former. Other than that though, the press release is a fresh breath of clear writing.

Re:Strange summary...

[imsabbel]

Er, reading comprehension?
Slow spinning pulsar== fast spinning pulsar - energy lost over a 1000s of years of synchrotron radiation.

Alt. theory : Pulsar leans to the extreme right

[Anonymous Coward]

...and FOX "NEWS" does the spinning for it.

Pulsars get sloshed every 15 to 300 milliseconds?

[Picass0]

Sounds like that's where the party is at.

Not that there's anything wrong with that.

[Slash Wrists]

My pulsar doesn't spin like that.

Pulosi Got Her Spin From...

[BoRegardless]

her liberal upbrining in San Francisco politics.

Spin is such a fundamental thing...

[gd23ka]

All wars are driven by spin. While we still have to settle for more earthly spin like the
lies behind "The war on Drugs" or the "War on Terror", it appears that someone has
declared the "War on Pulsars". Ludicrous as "War on Pulsars" sounds, it's just the sheer
mind-shattering stupidity of Fox News magnified to the intragalactic scale.

Re:Spin is such a fundamental thing...

[Hal_Porter]

I can see why the War on Drugs bothers you so much.

From Kipling's "Just-so Stories"

[sehlat]

"How the Pulsar Got Its Spin"

In the galaxy, once upon a time, O my Best Beloved, there was a
star, and it gave off light and a stellar wind. It fused hydrogen
to helium, and developed turblence and spots, and slowly grew old,
turning to burning helium, then heavier and really truly heavier
elements, until it grew a Great Iron Core. ...

Oh! Oh! I know!!!

[wramsdel]

Copernicus Rove?

He's the lesser-known twin.

Uhmm...

[OpenSourced]

How a pulsar gets its spin?

... from the Bush administration ?

Or, in legal circles...

[mangu]

"theory" is for science journalists as "allegedly" is for the crime pages. We all know it's true, but no one wants to risk the liability of a libel and slander suit.

Re:Or, in legal circles...

[Anonymous Coward]

Maybe for 'scientist journalists' but it shouldn't for scientists. They shouldn't be dogmatic at all. Instead, they should always have room to consider new interpretations of old data and make sense out of new data even when contradictory to current thinking. Throughout history commonly held truths have become well known falsehoods all too often. The more we probe reality the wierder it seems to get - so I'm not going to rule anything out.

Instead, I like to think in terms of probability. When you begin to state things as 'absolute fact' (sounds like a cocktail enjoyed by discerning scientist journalists everywhere) you start down a path that begs some questions about the nature of knowledge and knowing. Ultimately all statements (including this one) start with an assumption - an axiom - a leap of faith.

Those qualifiers aren't just some sort of way to communicate a wink-wink-nudge-nudge-'You and I both know it's really absolutely true but must pretend to admit that there is a possibility we may be wrong' message. Not at all. They don't speak to a dogmatic body of knowledge, but rather to the fundamental nature of the search for knowledge.

Don't sell those phrases short!

Similar Concept

[Rhesusmonkey]

Isn't that pretty much the same process by which Stella Got her Groove Back?

That's easy!

[7Prime]

EVERYONE knows how a pulsar get's spun...

Fox News!

I like to think of Pulsars as...

[ROMRIX]

The Universes Disco balls.
(take a look at Orion's Travolta move if you don't believe me)

Angular momentum conservation?

[rrohbeck]

Subject says it all. What else but the angular momentum of the original star determines the pulsar's rotation rate? The supernova process can only determine how that angular momentum is divided between the pulsar and the ejected mass. So does this new mechanism cause mass to be ejected off-center? The news release doesn't say much, unfortunately.

That's Oak Ridge, TENNESSEE

[Anonymous Coward]

Yeah the same Tennessee that everyone likes to refer to as red necks and hicks.

It's not like Oak Ridge's neighbor Knoxville has one of the highest ranking Ph.D per Capita ratings or anything either.

No

[brian0918]

The slashdot story text is taken directly from the Oak Ridge article. Try again.

Re:No

[exp(pi*sqrt(163))]

Having trouble telling the difference between:

researchers at Oak Ridge have shown that the spin of a pulsar is determined by the shock wave

and

According to three-dimensional simulations...the spin of a pulsar is determined...by the shock wave created when the star's massive iron core collapses.

?

There's a big difference between a tentative model suggested by a simulation that is explicitly described as 'plausible' and 'researchers have shown that...is determined'.

Maybe you'd like to try again.

It's Sparks, You Idiots

[pln2bz]

It's spinning because gravity rules, man! That's what they taught us in astrophysics class, or PE or something ... that even though plasma fills all of space and it consists of charged particles, it doesn't actually *do* anything. It *can't* be true that those charged particles in plasma might interact with one another en masse as plasma does in order to move charged particles through fields or voltage differentials in space, or that diffuse flows of energy might exist within the universe. There's no way. That would be lamerz! Definitely, before I'd consider something like that, I'd try to figure out some invisible matter that can pull the arms of spiral galaxies just enough to make them rotate with the rest of the plasma (dark matter) -- even though common sense would say that the large majority of the matter is at the center of the galaxy. And even though it really doesn't make much sense, I'd probably also bet that there are particles that gravitationally *repel* one another (dark energy). But, even though electricity over plasma can actually already do both attraction and repulsion, and even though space *is* plasma, it really *has* to be gravity that does that stuff and there *must* be particles there *somewhere*. I mean, that's what everybody *else* believes. This is ***SLASH-D0T***. And the scientists and those inventors can do *everything* these days. I mean, I heard that they saw stars that spin at the rate of a dentist's drill. And these dark hole things that suck everything in, but they can also have jets where all of that stuff that's sucked in can sometimes come back out and stuff. I wonder what it would be like to go there. Imagine if you had like these two black holes and there were these different dimensions and there was a string that connected them ... ! ... Wouldn't that be cool? We should test it out first with our cat though before we try it ourselves ...

I like astronomy. It's very creative. It makes you wonder, like, what's out there? What *is* the universe? Somebody once told me that it was made of plasma, but they also said that in order to make their homework easier, they were allowed to assume that the plasma had no resistance and could not carry currents, and that it was a fluid. It was weird because this isn't *anything* like what real plasma is. Those kids did a lot less homework. But they were kind of weird. They were all alike, and would tell people that they knew *everything*, and they wouldn't really listen when *you* tried to say something. I didn't want to hang out with them, but there were so *many* of them. I heard about these other playgrounds where these really cool people hung out where people didn't all try to be exactly alike and there were lots of smart people and stuff. I think it was a long time ago though.

You wanna hear something fucked up?! I *heard* that we can only see and interact with 4% of the matter of the universe. I know dude!!!!!! It's COM-PLETE-LY crazy! I mean, what *is* that other stuff, man? You know it's OUT THERE!!!!!!!!!!!!! Ha! And you know, sometimes when I'm driving all by myself down the road, and I'm really fucked up on shrooms, I start to wonder ... AM I IN IT? I know. I know ... Crazy, huh?!

You know, the other day, I was hanging out in my apartment by myself and my furniture all started to move towards one another. No, I wasn't trippin! Good one. No, that's *exactly* what they said happens with gravitational collapse. Matter will just be, like, hanging out and suddenly -- like BAM! -- or maybe slowly or something, when everything else is not happening in a vacuum that can disturb the process and stuff for like millions of years -- things start forming clumps. I was thinking of actually designing a new whippets dispenser that works like this -- you just put a dispenser in open air next to a bubble of nitrous oxide and it will condense and then you inhale. Cool, huh? I invented it

Spindowns

[Shitok]

I think the story ought to acknowledge the larger effect which comes from the stars initial angular momentum.

Our Sun (for example) rotates at the rate of around once per 25 days and has a radius of around 1 million km. If
it was to collapse into a neutron star without losing any mass the moment of inertia would go down by a factor
of (1,000,000 km/10 km)^2 = 10 billion. So the rotation rate would go up to 4500 times per second. The principle
is the same one that makes figure skaters spin-up when they bring their arms and legs closer to their bodies.

Clearly, it would not retain all of its matter when collapsing and you need to be several times heavier than the
sun in order to collapse into a neutron star. The fastest pulsars still only rotate at ~600x per second. But its
still a significant factor in the spin rate calculation.

Of course, then they spin down becomes of electromagnetic radiation. Some of them probably even spin down because
they are asymmetric and lose energy in the form of gravitational radiation.