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New Class of Pulsars Discovered

Soulskill posted more than 4 years ago | from the for-all-your-gamma-ray-needs dept.

Space 93

xyz writes "NASA's Fermi Gamma-ray Space Telescope has discovered a new class of pulsars which emit purely in gamma rays. A pulsar is a rapidly spinning neutron star, and of the nearly 1,800 cataloged so far, only a small fraction emit at frequencies higher than radio waves. The gamma-ray-only pulsar, which lies within a supernova remnant known as CTA 1, is silent across parts of the electromagnetic spectrum where pulsars are normally found, indicating a new class of pulsars. It is located 'about 4,600 light-years away in the constellation Cepheus. Its lighthouse-like beam sweeps Earth's way every 316.86 milliseconds. The pulsar, which formed in a supernova explosion about 10,000 years ago, emits 1,000 times the energy of our sun.'"

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First Pulsar Post (3, Funny)

Fishead (658061) | more than 4 years ago | (#25603009)

Odd thing is that the signal seems to be carrying a message. We have decoded it, and it seems to read: F-I-R-S-T---P-O-S-T-.

Re:First Pulsar Post (0)

Anonymous Coward | more than 4 years ago | (#25603095)

Every 316 Milliseconds? Do you know what else has that timing?

PEW-PEW-PEW, the sound of mah lazers!

Re:First Pulsar Post (0, Offtopic)

dotancohen (1015143) | more than 4 years ago | (#25603339)

Every 316 Milliseconds? Do you know what else has that timing?

PEW-PEW-PEW, the sound of mah lazers!

Sharks are silent predators.

Re:First Pulsar Post (3, Funny)

aliquis (678370) | more than 4 years ago | (#25604093)

Funny, over here the only thing I can hear is fap-fap-fap...

Re:First Pulsar Post (0)

Anonymous Coward | more than 5 years ago | (#25609279)

Message is encrypted should read S-M-A-L-L---P-E-N-I

Pulsar music (5, Interesting)

CRCulver (715279) | more than 4 years ago | (#25603015)

There was a recent Slashdot discussion [slashdot.org] on music from pulsars which didn't get quite the attention I wish it did. Along those lines, I'd again encourage all nerds here to check out Gerard Grisey's work Le Noire d'Etoile [amazon.com] for six percussionists. This work is based in part on the periodicity of a certain pulsar, and at one moment the performers pause while the sound of another pulsar is acquired with a radio telescope and relayed over speakers in the hall. This would definitely appeal to the many nerds here with an astronomy bent, but it sadly remains little-known outside of IRCAM circles.

Re:Pulsar music (1)

CRCulver (715279) | more than 4 years ago | (#25603081)

Ugh, I'm losing my French. The title is "Le Noir de l'Etoile". Sorry.

Re:Pulsar music (1)

Whiteox (919863) | more than 5 years ago | (#25608035)

I, of course, was going to pick you up on that... Apology accepted.

Re:Pulsar music (1)

pod (1103) | more than 5 years ago | (#25611899)

Along the same lines, I would recommend Arecibo (Atmosphere label) and Bad Sector (Old Europa Cafe, Waystyx) fairly obscure, but inspired by "astronomic" phenomena.

and it's pulsing (-1, Offtopic)

UncleWilly (1128141) | more than 4 years ago | (#25603029)

V-O-T-E-O-B-A-M-A

Re:and it's pulsing (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#25603047)

A couple weeks ago, while browsing around the library downtown, I had to take a piss. As I entered the john, Barack Obama -- the messiah himself -- came out of one of the booths. I stood at the urinal looking at him out of the corner of my eye as he washed his hands. He didn't once look at me. He was busy and in any case I was sure the secret service wouldn't even let me shake his hand.

As soon as he left I darted into the booth he'd vacated, hoping there might be a lingering smell of shit and even a seat still warm from his sturdy ass. I found not only the smell but the shit itself. He'd forgotten to flush. And what a treasure he had left behind. Three or four beautiful specimens floated in the bowl. It apparently had been a fairly dry, constipated shit, for all were fat, stiff, and ruggedly textured. The real prize was a great feast of turd -- a nine inch gastrointestinal triumph as thick as his cock -- or at least as I imagined it!

I knelt before the bowl, inhaling the rich brown fragrance and wondered if I should obey the impulse building up inside me. I'd always been a liberal democrat and had been on the Obama train since last year. Of course I'd had fantasies of meeting him, sucking his cock and balls, not to mention sucking his asshole clean, but I never imagined I would have the chance. Now, here I was, confronted with the most beautiful five-pound turd I'd ever feasted my eyes on, a sausage fit to star in any fantasy and one I knew to have been hatched from the asshole of Barack Obama, the chosen one.

Why not? I plucked it from the bowl, holding it with both hands to keep it from breaking. I lifted it to my nose. It smelled like rich, ripe limburger (horrid, but thrilling), yet had the consistency of cheddar. What is cheese anyway but milk turning to shit without the benefit of a digestive tract?

I gave it a lick and found that it tasted better then it smelled.

I hesitated no longer. I shoved the fucking thing as far into my mouth as I could get it and sucked on it like a big half nigger cock, beating my meat like a madman. I wanted to completely engulf it and bit off a large chunk, flooding my mouth with the intense, bittersweet flavor. To my delight I found that while the water in the bowl had chilled the outside of the turd, it was still warm inside. As I chewed I discovered that it was filled with hard little bits of something I soon identified as peanuts. He hadn't chewed them carefully and they'd passed through his body virtually unchanged. I ate it greedily, sending lump after peanutty lump sliding scratchily down my throat. My only regret was that Barack Obama wasn't there to see my loyalty and wash it down with his piss.

I soon reached a terrific climax. I caught my cum in the cupped palm of my hand and drank it down. Believe me, there is no more delightful combination of flavors than the hot sweetness of cum with the rich bitterness of shit. It's even better than listening to an Obama speech!

Afterwards I was sorry that I hadn't made it last longer. But then I realized that I still had a lot of fun in store for me. There was still a clutch of virile turds left in the bowl. I tenderly fished them out, rolled them into my handkerchief, and stashed them in my briefcase. In the week to come I found all kinds of ways to eat the shit without bolting it right down. Once eaten it's gone forever unless you want to filch it third hand out of your own asshole. Not an unreasonable recourse in moments of desperation or simple boredom.

I stored the turds in the refrigerator when I was not using them but within a week they were all gone. The last one I held in my mouth without chewing, letting it slowly dissolve. I had liquid shit trickling down my throat for nearly four hours. I must have had six orgasms in the process.

I often think of Barack Obama dropping solid gold out of his sweet, pink asshole every day, never knowing what joy it could, and at least once did, bring to a grateful democrat.

Re:and it's pulsing (0)

Anonymous Coward | more than 5 years ago | (#25609331)

Obamas asshole is not pink, does he look creamy white to you!

Re:and it's pulsing (-1, Troll)

Anonymous Coward | more than 4 years ago | (#25603193)

V-O-T-E-O-B-A-M-A

Fuck that shit... and your little asshole too!

I am going to be so happy when the election is over and who ever wins wins.

You Obama cock lickers are fucking ass wipes who need to be raped

Ass Wipes

Yeh that right go ahead and mod this one to hell, but that makes you a mod asswipe also

Re:and it's pulsing (-1, Offtopic)

glitch23 (557124) | more than 4 years ago | (#25603239)

So you are saying there is no intelligent life out there afterall?

Re:and it's pulsing (0)

Anonymous Coward | more than 4 years ago | (#25603767)

About as intelligent as someone who thinks "after all" is one word...

Re:and it's pulsing (1)

LVSlushdat (854194) | more than 4 years ago | (#25604045)

Your wish is NOT my command, Comrade UncleWilly...

Re:and it's pulsing (1)

OrangeTide (124937) | more than 5 years ago | (#25623899)

We gotta do what the TV tells us. It says it's a message of hope. I'm not sure what to hope for, but we're all real hopeful.

Do we need to have a President every 4 years? Can't we take a vacation once in a while?

Re:and it's pulsing (1)

rossdee (243626) | more than 4 years ago | (#25606225)

Its 4600 light years away. If there was intelligent life there, they are just finding out who won the trojan war, they don't know about Barack Obama yet.

This proves they're from Chicago... (2, Funny)

800DeadCCs (996359) | more than 4 years ago | (#25603099)

This proves they're from Chicagoland...
CTA....
3 busses will come within 316.86 milliseconds of each other,
then you'll wait 10,000 years for the next one.

Re:This proves they're from Chicago... (4, Funny)

dotancohen (1015143) | more than 4 years ago | (#25603335)

3 busses will come within 316.86 milliseconds of each other,
then you'll wait 10,000 years for the next one.

You obviously do not smoke. A surefire way to make that next bus come is to light one up.

Re:This proves they're from Chicago... (1)

Artuir (1226648) | more than 4 years ago | (#25606403)

Wait, light a cigarette or a bus up? I'd think lighting a bus on fire would defeat the purpose, but it would certainly draw attention.

Re:This proves they're from Chicago... (1)

MikeDirnt69 (1105185) | more than 5 years ago | (#25611381)

You can light the entire box, but if it's raining, no bus will ever arrive.

Re:This proves they're from Chicago... (1)

thesandtiger (819476) | more than 5 years ago | (#25607149)

A slight correction:

Three *nearly empty accordion buses* will quickly come, all of them the 29 State, and then you'll die of old age waiting for a 144.

Not that I'm bitter.

Technically (1)

Lord Byron II (671689) | more than 4 years ago | (#25603109)

Since "emitting" usually has an implied "per second" in it, we should be talking about the power it emits, not the energy.

Re:Technically (1)

Fluffeh (1273756) | more than 5 years ago | (#25608649)

What about the person who emits a "funky odor"? We don't start trying to quantify that little bastard :)

Gamma ray bursts and extinction events? (0)

Anonymous Coward | more than 4 years ago | (#25603117)

This sucker is "only" 3,000 light years away? Isn't earth in danger of an extinction event when a gamma ray burst occurs from something about 6,000 light years away?
http://en.wikipedia.org/wiki/Gamma_ray_burst [wikipedia.org]
Should we hide in our basements, crack our neighbour's heads open and feast on the goo inside?

Re:Gamma ray bursts and extinction events? (1, Funny)

Anonymous Coward | more than 4 years ago | (#25603183)

> Should we hide in our basements
Check

> crack our neighbour's heads open and feast on the goo inside?
Now theres something on your to do list!

Re:Gamma ray bursts and extinction events? (1)

thomasdz (178114) | more than 4 years ago | (#25603223)

> crack our neighbour's heads open and feast on the goo inside?

Now theres something on your to do list!

The original Simpson's quote is from "Homer the Vigilante" http://www.simpsoncrazy.com/episodes/1F09 [simpsoncrazy.com]

Re:Gamma ray bursts and extinction events? (4, Informative)

rasputin465 (1032646) | more than 4 years ago | (#25603385)

Isn't earth in danger of an extinction event when a gamma ray burst occurs from something about 6,000 light years away?

Although this thing does emit gamma rays, in discreet packets, this is not an example of the phenomenon knows as Gamma Ray Bursts (GRBs). The "burst" in a genuine GRB lasts much longer (seconds or minutes as opposed to milliseconds), happens only once, and contains orders of magnitude greater energy.

So when we say we're screwed if a GRB happens within 6,000 lt-yr of Earth (and it's pointed in our direction), that's absolutely true, but it doesn't apply to pulsars.

Re:Gamma ray bursts and extinction events? (2, Funny)

ceoyoyo (59147) | more than 4 years ago | (#25603883)

I've found that gamma rays aren't the least bit discreet. They either make things disintegrate or turn people into man-spider hybrids.

Re:Gamma ray bursts and extinction events? (0)

Anonymous Coward | more than 5 years ago | (#25606909)

no no no. that's patently false. only bites from radioactive spiders turn people into man-spider hybrids.

if the gamma rays don't disintegrate you, they make you turn green when something pisses you off.

Re:Gamma ray bursts and extinction events? (1)

ceoyoyo (59147) | more than 5 years ago | (#25607013)

Whoops, I knew it was one or the other. The basic thesis is sound though - a giant green guy with an anger management problem is even LESS discreet.

Re:Gamma ray bursts and extinction events? (1)

techno-vampire (666512) | more than 5 years ago | (#25608751)

Kids today. They don't even understand any more that gamma rays only have an effect on man-in-the-moon marigolds.

Re:Gamma ray bursts and extinction events? (1)

Whiteox (919863) | more than 5 years ago | (#25608157)

Earth vs the Spider is the more thoughtful movie.
http://www.imdb.com/title/tt0282178/ [imdb.com]

Re:Gamma ray bursts and extinction events? (1)

hesaigo999ca (786966) | more than 5 years ago | (#25611017)

Or give them green eyes, and make them lift cars over their heads.

Its proximity to earth is a good thing! (1)

unassimilatible (225662) | more than 4 years ago | (#25604507)

The pulsar, which formed in a supernova explosion about 10,000 years ago, emits 1,000 times the energy of our sun.

1. ??
2. Capture energy with solar panels
3. Profit

Re:Its proximity to earth is a good thing! (5, Informative)

Gil-galad55 (707960) | more than 4 years ago | (#25604537)

Sorry, its high luminosity is more than offset by its distance of kiloparsecs. The relevant quantity is flux, which goes like luminosity/distance^2.

Re:Gamma ray bursts and extinction events? (1)

AliasMarlowe (1042386) | more than 5 years ago | (#25613875)

Should we hide in our basements, crack our neighbour's heads open and feast on the goo inside?

I am interested in your ideas and wish to subscribe to your newsletter.

I got a C in (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#25603137)

Quantum mechanics you insensitive prick!

Re:I got a C in (4, Funny)

morgan_greywolf (835522) | more than 4 years ago | (#25603353)

Quantum mechanics you insensitive prick!

If only you hadn't looked at the report card. Then, your grade could've been an A or an F, and you wouldn't have known until you looked at the report card, thus collapsing the waveform.

And now you know why you only got a C.

Re:I got a C in (1)

Chris Burke (6130) | more than 4 years ago | (#25604461)

Yeah, but no employer, even for a quantum mechanics related job, wants to hear that you may or may not have graduated with a degree.

Re:I got a C in (1)

omuls are tasty (1321759) | more than 5 years ago | (#25610125)

Clearly you've never sought work at Schroedinger's Pet Store.

Re:I got a C in (0)

Anonymous Coward | more than 5 years ago | (#25607681)

Quantum mechanics you insensitive prick!

If only you hadn't looked at the report card. Then, your grade could've been an A or an F, and you wouldn't have known until you looked at the report card, thus collapsing the waveform.

And now you know why you only got a C.

I got a dead cat.

Re:I got a C in (1)

InfiniteLoopCounter (1355173) | more than 5 years ago | (#25606781)

Quantum mechanics you insensitive prick!

That's because you forgot to observe that all the other students added in an extra box to the true or false and multiple choice sections.

Next time you too might want to add in "true and/or false", d.) "some possible combination of (a), (b), and (c)." to all these questions.

Emitted or recieved (1)

EdZ (755139) | more than 4 years ago | (#25603191)

It's not mentioned in the article, and I assume it's so obvious that it was ruled out before announcement, but is there anything to suggest that the pulsar is pulsing across all frequencies up to Gamma, and that intervening matter is simply blocking all but the high-energy Gamma portion of the pulse? Or am I just mixing up black-body emission and emission by electron's jumping a band-gap.

Re:Emitted or recieved (2, Informative)

glitch23 (557124) | more than 4 years ago | (#25603285)

It's not mentioned in the article, and I assume it's so obvious that it was ruled out before announcement, but is there anything to suggest that the pulsar is pulsing across all frequencies up to Gamma, and that intervening matter is simply blocking all but the high-energy Gamma portion of the pulse?

Yes it was mentioned:

This discovery by Fermi is different because it is a purely gamma-ray pulsar. The star is silent across parts of electromagnetic spectrum where pulsars are normally found and hints at a whole population of previously unsuspected pulsars waiting to be picked out of the heavens.

Re:Emitted or recieved (1)

EdZ (755139) | more than 4 years ago | (#25603749)

My point was: did they merely not DETECT wavelengths other than Gamma, or have they shown that wavelengths other than Gamma are not EMITTED? No mention is made of what tests can and/or have been done to determine which is true.

Re:Emitted or recieved (1)

ceoyoyo (59147) | more than 4 years ago | (#25603927)

It would have to be some pretty special intervening dust to block everything but gammas. Astronomers usually use radio and infrared to see through dust.

Re:Emitted or recieved (1)

Gil-galad55 (707960) | more than 4 years ago | (#25603969)

As I noted below, there is surely radio emission -- we are just not positioned to see it. The implication is that gamma ray emission originates higher in the pulsar magnetosphere than radio emission, so it paints a broader "beam" on the sky as the pulsar rotates.

Re:Emitted or recieved (2, Interesting)

Gil-galad55 (707960) | more than 4 years ago | (#25603813)

The radio emission is believed to come from a small patch near the surface of the neutron star called the polar cap. Hence, to see it, the pulsar has to be aligned just so with the line of sight to the Earth. Gamma ray emission appears to originate at a higher altitute, so there are more orientations of the pulsar with respect to the line of sight where we can see gamma rays. It's a geometrical effect.

It's all supposition (0, Redundant)

Anonymous Coward | more than 4 years ago | (#25603203)

No natural object is spinning that fast. We need to re-examine other concepts, such as pulsars as interstellar beacons.

Re:It's all supposition (5, Funny)

dotancohen (1015143) | more than 4 years ago | (#25603327)

No natural object is spinning that fast.

You are obviously not aware about the United States forefathers in their graves, knowing what is going on in that nation.

Re:It's all supposition (0)

Anonymous Coward | more than 4 years ago | (#25603543)

No natural object is spinning that fast.

You are obviously not aware about the United States forefathers in their graves, knowing what is going on in that nation.

I, for one, welcome our pulsar power-generating patriotic zombie overlords

Re:It's all supposition (1)

qeveren (318805) | more than 4 years ago | (#25603419)

The equator of something like this is only moving at around 200km/s, what's unreasonable about that?

Re:It's all supposition (0)

Anonymous Coward | more than 4 years ago | (#25603879)

Electrons in orbit????????? Are you truly this stupid?

you are right (0)

Anonymous Coward | more than 4 years ago | (#25603893)

It is a mass relay.

Re:It's all supposition (1)

ceoyoyo (59147) | more than 4 years ago | (#25603947)

You'll find if you figure out how much circular momentum there is in a star, it would be very, very odd if neutron stars were NOT spinning that fast.

Of course a flat statement of unsubstantiated "fact" is the beginning of all good scientific statements.

Actually that is what they thought at first (1)

gatkinso (15975) | more than 4 years ago | (#25606389)

They thought is was a signal from another civilization, and they called pulsars LGM's (for Little Green men).

That is a true story!

Re:It's all supposition (0)

Anonymous Coward | more than 5 years ago | (#25622701)

No technological object is generating that much power.

Puny Humans (0)

Anonymous Coward | more than 4 years ago | (#25603245)

Somehow we have to evolve to survive intense space problems. I suggest we all go selectively breed and send our offspring to face trials of horrors. It's for the good of humanity.

Re:Puny Humans (1, Insightful)

Fex303 (557896) | more than 4 years ago | (#25603309)

I suggest we all go selectively breed and send our offspring to face trials of horrors. It's for the good of humanity.

Dad? Is that you?

Re:Puny Humans (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#25607541)

Somehow we have to evolve to survive intense space problems. I suggest we all go selectively breed and send our offspring to face trials of horrors. It's for the good of humanity.

Or vote Obama.

"Under my plan of a cap and trade system, electricity rates would necessarily skyrocket."

Yeah, combine that with a massive tax hike and that'll do wonders for the US economy.

Trials of horrors indeed.

Re:Puny Humans (1)

Whiteox (919863) | more than 5 years ago | (#25608137)

I suggest we all go selectively breed and send our offspring to face trials of horrors.

Could we send the telephone sanitizers first?

Pure gamma rays only? (0, Offtopic)

$RANDOMLUSER (804576) | more than 4 years ago | (#25603287)

HULK SMASH!!!

So, does this imply anything special? (3, Interesting)

Jugalator (259273) | more than 4 years ago | (#25603355)

Is there more to this than just a new object? Does it imply that certain models on how pulsars form need to be refined? Gamma rays are also incredibly high energy, what does it imply as for the structure of the pulsar that it doesn't emit lower frequencies?

What I'm getting at is pretty much that the article seem to just pass this off as a "ok, we have a new kind of pulsar here" without any follow up questions raised. IS there any questions to raise? Does this all fit neatly into what we know about pulsars, and is it easily explained why this one doesn't emit in lower frequencies, and only in a very high energy one?

I'm also surprised there are so much "junk" like the "yourmumisapulsar" tag and Obama posts, etc. Come on now, this is Slashdot, if I want the other stuff on science stories, I can read Digg. :-(

Re:So, does this imply anything special? (2, Interesting)

play_in_traffic (946193) | more than 4 years ago | (#25603487)

Gamma ray does not in fact imply much about energy (although they can be incredibly high energy). It is just another photon. What it does say is that it comes from a nuclear interaction rather than an electronic transition (electron mediated). This most certainly does say something about the nature of the pulsar that is generating this "beam" of ionizing radiation. Please let me know when you have a new model that accounts for this.

Re:So, does this imply anything special? (5, Interesting)

Gil-galad55 (707960) | more than 4 years ago | (#25603845)

No, gamma rays from pulsars are much higher energy than those associated with nuclear transitions (typical scale: 1 MeV; pulsar emission spectra peak at 1 GeV, 1000 times greater).

Pulsars have extremely strong electromagnetic fields and are hence able to accelerate electrons up to very high energies. These electrons then scatter low energy photons upwards in energy to the gamma ray regime.

To answer GP's question, observing radio-quiet pulsars like this on in CTA1 tells us more about the gamma ray emission mechanism. Several different models exist, and the primary difference is where in the pulsar's magnetosphere gamma rays are created. In the polar cap model, gamma rays originate in a small patch near the magnetic pole, the same place as the radio emission. So, if gamma rays predominantly come from the polar cap, we shouldn't see radio-quiet pulsars. Hence, this pulsar favors an emission model with gamma rays from higher altitude, in the so-called outer gaps and slot gaps.

Re:So, does this imply anything special? (5, Interesting)

Bemopolis (698691) | more than 4 years ago | (#25604419)

Well, there should be a gamma-ray line at about 511 keV (0.024 A) in all pulsars, since the polar magnetic field strength generates electron-positron pairs, which then annihilate. This produces a broad line (it's a two-photon process), whic has been observed in other pulsars (iirc).

What's surprising here is the absence of thermal emission from other plasma in the magnetic field which, as you imply, impacts the pulsar at the magnetic poles to produce heat (and hence light.) The question is then, where is this plasma that we usually see trapped in the pulsars' magnetic field. Since this pulsar is no longer inside its parent supernova remnant bubble, I would argue that that this plasma has just been left behind. Why the general interstellar medium has not somewhat replaced it is a bit of a mystery, but that's why we build telescopes in the first place: to find out.

Re:So, does this imply anything special? (1)

Gil-galad55 (707960) | more than 4 years ago | (#25606051)

Well, there is clearly enough circumstellar (circumpulsar?) material to generate the pulsar wind nebula detected in X-rays, but as with all collisionless shocks, this material must be tenuous.

Re:So, does this imply anything special? (1)

jmichaelg (148257) | more than 4 years ago | (#25604479)

Gamma ray does not in fact imply much about energy (although they can be incredibly high energy). It is just another photon.

Huh!? Does Planck's constant ring a bell? ...

E = h * f

Gamma rays are very high frequency, hence they're highly energetic.

In future news... (2, Funny)

iamapizza (1312801) | more than 4 years ago | (#25603417)

... we'll discover yet another class of pulsars, known as category WEB20, which emit purely Beta rays. And they reflect stuff!

Would the Physicists Please Stand Up (1)

HungSoLow (809760) | more than 4 years ago | (#25603505)

Assuming a Neutron star is actually solely made up of Neutrons ... how does it emit electromagnetic radiation when there's no charged particles? Is it just the minute amount of charged particles that reside that emit the radiation, or is it perhaps charged particles around the star, orbiting violently that emit?

Re:Would the Physicists Please Stand Up (5, Informative)

Gil-galad55 (707960) | more than 4 years ago | (#25603877)

The neutron star surface does emit thermal X-rays because it is hot. However, the electromagnetic radiation originates outside the neutron star, in its magnetosphere.

Pulsars have extremely strong magnetic fields and rotate anywhere from 1-to-1000 times a second. Just like an electric generator, this produces huge electromagnetic fields, and these accelerate electrons to very high energies indeed. These electrons than bang into photons and give them a large chunk of energy in a process called inverse Compton scattering, and we get gamma rays.

(This is the so-called leptonic channel; it is also possible some gamma rays are produced via pions, but the origin of the energy is the same: the huge electromagnetic fields generated by this spinning magnetic dipole.)

Re:Would the Physicists Please Stand Up (1)

pseudochaos (1014063) | more than 4 years ago | (#25604625)

If pulsars are comprised almost entirely of neutrons, then how could they hold on to their electrons which are needed for magnetism (for there is no magnetism without an electrical field, if Michael Faraday is to be believed)?

Since neutrons hold no electrical charge, they wouldn't possess an electron shield, which should tell us that neutron stars have no electricity, and therefore no magnetic sphere. Shall we all collectively go back to the drawing board, or did I (hopefully) miss something here?

Re:Would the Physicists Please Stand Up (1)

gatkinso (15975) | more than 4 years ago | (#25606241)

From what I remember from a sophmore astronomy class, the matter inside the neutron stars is a liquid mixture of neutrons as well as electrons, is a superconductor, and is spinning around at an incredible rate - thus producing the immense magnetic field.

Well, atleast this is what some brainy f-ers theorized. Who knows. All I know for sure is that I was a math major, and took that class because I thought it would be easy. Such a fool in my youth.

Re:Would the Physicists Please Stand Up (1)

pseudochaos (1014063) | more than 5 years ago | (#25606817)

Yes, but what's keeping the electrons trapped in this superconducting liquid? Surely the gravity isn't strong enough to overcome the momentum of electrons from propelling them into space.

Re:Would the Physicists Please Stand Up (1)

gatkinso (15975) | more than 5 years ago | (#25629893)

It is the electrons that make it a superconductor. They are floating around in that neuton degenerate liquid doing fuck knows what, and even of the pressure and gravity were not enough to trap them, the mile or so thick solid crust would.

Re:Would the Physicists Please Stand Up (1)

pseudochaos (1014063) | more than 5 years ago | (#25631291)

I find this extremely unlikely, as gravity is a lot weaker than electromagnetic force. Also, what's this solid crust made out of? Iron? Copper? Some other *conductive* material? (In case you missed it: Just because it's solid to us doesn't mean that electrons can't travel through it)

Re:Would the Physicists Please Stand Up (1)

gatkinso (15975) | more than 5 years ago | (#25653591)

Solid crust is mainly iron and cobolt nuclei packed together at electron degenerate densities.

It is wascky - wiki it for yourself... or better yet crack an intro to Astronomy text. It is pretty intense.

And while I don;t doubt that I have misstated things, I have painted a fairly accurate picture with very broad strokes.

Re:Would the Physicists Please Stand Up (0)

Anonymous Coward | more than 5 years ago | (#25667673)

Yes, but wouldn't the electric force repel these nuclei apart (as it's stronger than gravity), thereby allowing them enough space to acquire electrons like normal?

Moreover, how in the world would we prove or falsify that this is the actual configuration of neutron stars || (more specifically:) pulsars?

It seems to me we're just making it up as we go, but perhaps I'm just being jaded and really *do* need to crack some more books.

Re:Would the Physicists Please Stand Up (1)

gatkinso (15975) | more than 5 years ago | (#25674211)

Nope - the gravity is too strong. Gravity is very wimpy when dealing with low mass - say like the mass of the earth, but exceed the Chandrasekhar limit of mass an all of a sudden gravity becomes more powerful than ANY known force.

So powerful that at about pi * Chandrasekhar light itself cannot escape.

Quiz - why iron (and a bit of cobalt)? Hint: carbon, nitrogen, oxygen.

It is my personal belief that there is no other force other than gravity, and that when God/god/gods/G-d/ad mauseum created the universe all s/he/it did was create gravity, and disturb it.

Re:Would the Physicists Please Stand Up (0)

Anonymous Coward | more than 5 years ago | (#25755605)

Most of the electrons are orbital rather than free; the atoms they are part of are a mix of electrically neutral and electrically positive ions. Free electrons move thermally (slowly) for the most part, faster electrons would have to arise from reactions which produces electron-positron pairs, and this would be visible in the gamma spectrum (from positron annihilation) -- also such fast electrons likely would be ejected at a large multiple of the escape velocity through a medium that is largely electrically neutral (so the interaction cross section is fairly small, give or take inverse compton scattering). So we can generally ignore fast electrons: they just fly off into space.

While the temperatures are very high in the degenerate phase, leading to ionization, this is unlikely to be completely uniform, leading to hotter areas which are more likely to have a net positive charge, and cooler areas which are more likely to have a net neutral or even slightly negative charge.

The equation of state of a neutron star is simply not known, but the expectation is that from the crust inwards, there is a increase in the number of neutrons per proton per nucleus; the nuclei "eat" electrons (or perhaps there is some hadronization effects among protons, or some pion/kaon physics involved) and become more neutral and heavier. The pressures from the self-gravitation keep these high-atomic-mass/low-atomic-number nuclei from decaying.

A flow of electrons from near the surface corewards to satisfy the excess demand for electrons (nuclei towards the core are very hot and thus ionize readily, and the protons are busily consuming electrons in the process of becoming neutrons) may explain a strong magnetic field. Remember that ordinary stars have magnetic fields too, even though they are on the whole electrically neutral. In ordinary stars, much of that magnetic field is caused by dissociation of electrons from hot atoms, followed by subsequent capture of free electrons by the resulting positive ions.

So, like with an ordinary star, it is not the rotation of the neutron star that produces its magnetic field, but rather the convection-like flow of its degenerate phase, analogous to the actual convective flow of the plasma phase in normal stars. The "dynamo" is local flow of matter, rather than rotation of the whole body.

However, since the whole body is rotating, there may be differential rotation if the degenerate phase is sufficiently mobile (like a liquid). The rotation is fast enough that this could easily lead to a rope-like winding of flux (you could think of this as the field lines lagging behind the rotation of the surface), which would magnify the field's intensity. Magnetars may work that way.

More tersely and directly, free electrons are responding to local changes in net positive charge -- they migrate to areas of highly positive charge, and are thermally shaken out of areas of weakly positive or neutral charge. Although the gravitational potential is strong within the neutron star, within an inertial frame chosen such that an electron experiences accelerations only from the star's gravitation and the star's charge, the electron will experience a much larger acceleration from the electromagnetic force than from the force of gravity -- by many orders of magnitude.

So an electron will move towards net positive charge, and probably be captured by an ion, and then sink (the deionized atom has more mass) and get squashed into a proton to form a neutron (same mass, but now a positively charged ion), or heat up and dissociate from the ion (leaving behind a lower-mass but positively charged ion). Models along this line of thought work fine for pure random walks by the electron; it works even better where the electron's walks are constrained by magnetic fields.

Re:Would the Physicists Please Stand Up (1)

HungSoLow (809760) | more than 4 years ago | (#25604693)

But I still don't see how neutral matter can produce radiation? Thermal radiation occurs because of electrons jumping between energy levels, but in an all neutron soup, there's no jumping (none that I can imagine). Moreover, how can neutron matter produce a magnetic field (I'm probably just missing some known mechanism)? I can see that charged matter interacting with the magnetic field produces radiation (just like the northern/southern lights) but my question is where does that field come from? Is there perhaps a neutron --> proton + electron --> neutron reactions that occur on a regular basis with radiation being a byproduct?

Re:Would the Physicists Please Stand Up (3, Interesting)

HungSoLow (809760) | more than 4 years ago | (#25604747)

Sorry about replying to my own comment:

Wikipedia - Neutron Star [wikipedia.org]

"On the basis of current models, the matter at the surface of a neutron star is composed of ordinary atomic nuclei as well as electrons."

It seems as one moves deeper into the star, the more it becomes a pure sea of neutrons. So all the charged matter on the surface, rotating around like crazy, creates the magnetic field which then causes the emission of radiation.

Re:Would the Physicists Please Stand Up (1)

PPH (736903) | more than 4 years ago | (#25604863)

Perhaps, a better question would be: Does the thermal radiation emitted from a neutron star originate from the neutrons themselves? If so, through what mechanism? Or is this radiation emitted by the star's surrounding atmosphere (gas cloud) interacting with the star's spinning magnetic field?

Neutrons, by themselves, do have a magnetic moment [wikipedia.org] .

Re:Would the Physicists Please Stand Up (1)

gatkinso (15975) | more than 4 years ago | (#25606325)

The star was very hot (as you might imagine) when it collapsed after the super nova event. Not massive enough to form a black hole, the very very dense neutron matter stopped the collapse. All protrons and most electrons (a 1-1 relationship) were squeezed into neutrons forming a solid crust, a liquid "mantle" of neutrons and electrons, and possibly a solid core, but no one really knows what the interior is like.)

The resultant body is very small - about the same diameter as the Washington DC beltway. It is still hot as fuck (you think?). However it is also very small, with the following results: 1) it will take a long time for the heat to radiate away from such a small surface area, and 2) conserving angular momentum, it started to spin really really fast.

With the resultant spin, a gigantor magnetic field is produced.

The gravity of this object is very strong - a feather dropped onto it from 1 AU will produce the same amount of energy as an exploding 3 megaton nuclear warhead when it hits the surface. Some of this radiation and shit gets channelled away from the object from the poles. Since the thing is spiining and wobbling, occaisionally one of these poles point toward earth... then away... then back... sweeping the beam of particles and shit produced by matter falling on the surface across our radio telescopes... producing the pulsing effect that gives it it's name.

The period of these events is very small. Like I said, that f-er is spinning fast as shit.

That is what I remember, anyway. Most of that is probably wrong. Sigh. I am getting old.

Re:Would the Physicists Please Stand Up (1)

niklask (1073774) | more than 4 years ago | (#25605267)

But I still don't see how neutral matter can produce radiation? Thermal radiation occurs because of electrons jumping between energy levels

Thermal radiation is solely due to the fact that the object has a temperature. Planck's law describes the spectrum of the radiation emitted by a black body.

but in an all neutron soup, there's no jumping (none that I can imagine). Moreover, how can neutron matter produce a magnetic field (I'm probably just missing some known mechanism)?

Indeed. See below.

I can see that charged matter interacting with the magnetic field produces radiation (just like the northern/southern lights) but my question is where does that field come from? Is there perhaps a neutron --> proton + electron --> neutron reactions that occur on a regular basis with radiation being a byproduct?

Yes. As you found out yourself, a neutron star is not perfect. There is always a small percentage of protons and electrons, mostly in the surface crust. As the neutron star is rapidly spinning, this creates a strong magnetic field.

Re:Would the Physicists Please Stand Up (1)

The_Wilschon (782534) | more than 5 years ago | (#25613781)

A gas of neutrinos, no matter how hot, should not emit blackbody radiation simply because neutrinos do not couple to photons. Oh, they do indirectly (through a W or some such), but that's gonna be a much higher order process and not particularly significant.

Re:Would the Physicists Please Stand Up (1)

gatkinso (15975) | more than 4 years ago | (#25606207)

Matter falling onto the stars surface, getting all combobulated, and the resulting radiation from the combobulation shot out at the magnetic poles (which are rotating on a different axis than the star iself) is basically how I remember it from long ago.

Admittedly, some minor details are being glossed over.

But actually, "combobulated" is not a bad summary of the series of lectures in a long ago Astronomy 201 class that covered pulsars.

Name it the Al Gore Pulsar (1)

Nom du Keyboard (633989) | more than 4 years ago | (#25605903)

The pulsar, which formed in a supernova explosion about 10,000 years ago, emits 1,000 times the energy of our sun.

Talk about Global Warming!

To be that hot, what is it made of? (1)

misterjava66 (1265146) | more than 5 years ago | (#25611333)

To be that hot, that it only shines in gamma, what could it be made of?
Obviously it is some form of degenrate matter, but can a quark-star get that hot?
Does this level of heat, require a size so small that a quark-star is not suffiecient?

Just wondering, does anyone have a calc as to how hot something realatively-big like
a nuetron star should be vs. how hot something much smaller like a quark-star should
be? Can we measure the size of the beam source by some means?

Re:To be that hot, what is it made of? (1)

niklask (1073774) | more than 5 years ago | (#25611901)

To be that hot, that it only shines in gamma, what could it be made of? Obviously it is some form of degenrate matter, but can a quark-star get that hot? Does this level of heat, require a size so small that a quark-star is not suffiecient?

Just wondering, does anyone have a calc as to how hot something realatively-big like a nuetron star should be vs. how hot something much smaller like a quark-star should be? Can we measure the size of the beam source by some means?

Why do you assume that the gamma-ray radiation is thermal, which it in fact is not.

Pulsars accelerate ions to high energy levels due (1)

mmell (832646) | more than 5 years ago | (#25617781)

to incredibly high magnetic fields combined with high rotational velocities . . .

So . . . has any pulsar ever been gobbled up by a microscopic black hole, or turned into strange matter (stranglets), or caused a quantum vacuum explosion? No?

GO CERN!

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