Singularity - Black Holes, Gamma Rays, Magnetars, etc

SBird · 2004-03-31 14:45:11

Mark - no problem, I'm glad you brought up your points - it's entirely possible that some sort of imaging innovation occurred that I had missed. The important thing is that we don't know if singularities can exist. The singularity is what gives us all sorts of thing like wormhole sand time travel - it's also the source for all sorts of problems like entropy preservation and spacetime breakdown. Personally, I think that a lot of physicists would love to be able to get rid of the things.

However, for all practical intents, let's assume that the things actually exist. There's certainly a lot of evidence, as you mention, that black hole-like objects exist.

ecrasez -
The galactic black holes are truly stupendous beasts. I believe that the one at the center of M87 is supposed to be about 2 billion times the mass of the sun. There's a movie of astronomical observations of some stars at the center of our own galaxy swirling around the core black hole there. If I can dig it up, I'll post the link here.

Wait, I found it! [http://www.mpe.mpg.de/www_ir/GC/intro.html]Here it is. The animation is a 6 meg gif picture but well worth the download wait. Keep in mind when watching the movie, that it's taken over a 14 year period of time.

I'll try to post a message with some more detail about the black hole stuff in a day or two, I'm crazy busy right now.

Palomar · 2004-03-31 15:10:31

I apologize for hijacking the thread over such a nitpicky point. I guess given the title of the thread I should have realized you were talking about singularities and not black holes in general.

*Hi Mark:

I started the thread, and it generally has lain dormant most of the time. Please, talk about black holes all you want!

I originally created the thread regarding a question I had about the "Singularity" (question answered), and now I'm more than happy to have ongoing discussions as we've had in the past day or two.

***Keep talking, please.*** I -don't- feel you're "hijacking" or "nitpicking" anything...on the contrary!

By the way, I wanted to mention that the documentary I saw last year definitely gave me the impression (which could be totally wrong of course) that the universe's existence is dependent upon supermassive black holes.

--Cindy

::EDIT:: SBird wrote: "There's a movie of astronomical observations of some stars at the center of our own galaxy swirling around the core black hole there. If I can dig it up, I'll post the link here...
Wait, I found it! Here it is. The animation is a 6 meg gif picture..."

*Great, thanks. Am opening it now.

Palomar · 2004-03-31 15:49:45

There's a movie of astronomical observations of some stars at the center of our own galaxy swirling around the core black hole there. If I can dig it up, I'll post the link here.
Wait, I found it! [http://www.mpe.mpg.de/www_ir/GC/intro.html]Here it is. The animation is a 6 meg gif picture but well worth the download wait. Keep in mind when watching the movie, that it's taken over a 14 year period of time.

*This is fantastic. I notice particularly how that one star enters in from the upper left-hand corner (top image), seems to hit something and then seems to bounce backwards.

Hopefully I'll find the explanation in the article itself.

I've never seen something like this before, so thanks a lot SBird.

--Cindy

Mark Friedenbach · 2004-03-31 20:15:41

The important thing is that we don't know if singularities can exist. The singularity is what gives us all sorts of thing like wormhole sand time travel - it's also the source for all sorts of problems like entropy preservation and spacetime breakdown. Personally, I think that a lot of physicists would love to be able to get rid of the things.

Yeah. You're original point (which I misinterpreted) was that black holes might have ordinary structure and need not be a singularity. I agree completely and hope that this is the case. It'd certainly make the physicists I know sleep better at night

I notice particularly how that one star enters in from the upper left-hand corner (top image), seems to hit something and then seems to bounce backwards.
Hopefully I'll find the explanation in the article itself.

If you look very closely, I think you'll see that it does loop around object (the red cross). The reason why it looks like it switches direction (I'm guessing here, but I'm pretty sure) is because we're looking at its orbit edge on. It's really a curved orbit like all the others, but we just can't see that from the angle we're looking at.

dicktice · 2004-04-01 09:41:33

Cindy: Ridiculously, I felt terribly depressed at your description of Adromeda colliding with Milky Way in 3 billion years or so, with us becoming toast even before the Sun's lifetime is up. From childhood, being raised on the old pulp science fiction, I'd always assumed we'd have gone away before old Sol went West, and found a younger sun with a New Earth to colonize. . . . I'm okay now though, but you had me going there for a while. April Fool's Day, Right?

Palomar · 2004-04-01 10:06:24

Mark: "The reason why it looks like it switches direction (I'm guessing here, but I'm pretty sure) is because we're looking at its orbit edge on. It's really a curved orbit like all the others, but we just can't see that from the angle we're looking at."

*Hi Mark. Thanks

Dicktice: "Cindy: Ridiculously, I felt terribly depressed at your description of Adromeda colliding with Milky Way in 3 billion years or so, with us becoming toast even before the Sun's lifetime is up. From childhood, being raised on the old pulp science fiction, I'd always assumed we'd have gone away before old Sol went West, and found a younger sun with a New Earth to colonize. . . . I'm okay now though, but you had me going there for a while. April Fool's Day, Right?"

*Well, I don't know what to say. I like to hope humankind will have achieved extragalactic travel and colonization by then. Maybe there is another Sol "out West"...way out west, far beyond the Milky Way's edge.

I wonder what the collision and merger of two supermassive black holes is like...the documentary didn't go into extreme detail. How do two objects of that nature "come together"? ??? Very violently, I presume.

--Cindy

SBird · 2004-04-01 12:48:57

Cindy: Ridiculously, I felt terribly depressed at your description of Adromeda colliding with Milky Way in 3 billion years or so, with us becoming toast even before the Sun's lifetime is up. From childhood, being raised on the old pulp science fiction, I'd always assumed we'd have gone away before old Sol went West, and found a younger sun with a New Earth to colonize. . . . I'm okay now though, but you had me going there for a while. April Fool's Day, Right?

That reminds me of an old story I heard. I'm not certain if it's true or urban legend but I like it nonetheless.

Right after giving a public planetarium presentation about the history and future of the solar system, an astronomer is approached by a woman from the audience. Looking quite concerned, the woman asks him, "Excuse me, how long did you say it would take before the sun turned into a red giant and destroys the Earth?"

"Oh, about 5 billion years or so."

"Oh, thank goodness, I thought you said 5 million years!"

SBird · 2004-04-02 12:50:14

ecrasez - the coillision of two galactic-size black holes is something I dont even want to think about. The energy released from such an encounter is probably sufficient to wipe out most of the life in surrounding several galaxies.

OK, as promised, here's a more user-friendly version of what I posetd a few days ago:

Black holes or singularities are the end result of the collapse of a large star. What happens is that the core ofa star is heated up to tremendous temperatures by the weight of the overlying gas. As a result, fusion occurs and stars produce tremendous amounts of energy. Eventually, all of the hydrogen in a star gets used up. The star then goes on to start fusing hydrogen nuclei and other heavier nuclei. At this point, IIRC, out sun is burning on a mix of hydrogen and helium. The heavier elements don't fuse as well, however. Asa result, the energy coming out of the star core drops. The energy coming out of the core pushes up on the upper layers of the star. As that energy drops, the upper layers push down on the core harder, heating it up even more. As the temperature goes up, the heavy nuclei start fusing more effectively, bringing the outward energy pressure up again until the star reaches a new equilibrium.

The result is that over time, the star's core gets denser and hotter as it goes to heavier and heavier elements for the fusion process. This causes the star to heat up and start expanding. The sun's eventual change into a red giant is a result of this process.

What eventually happen is that iron builds up in the core. Iron is the most stable atomic nucleus so fusion of iron nuclei actually sucks up energy rather than generating it. Therefore, iron acts as a poison for the star. As iron concentrations go up, the process of the star's core getting hotter and denser keep going up until a critical point is reached.

For the sun and other smaller stars, what happens is that the star just dies and goes out. The outer layers are blasted off in a final moderate nova and the core is an electron degenerate matter. (a description of degenerate matters will follow) Since it's not dense and heavy enough to collapse the electron degenerate matter any further, the core just sits there and slowly cools off in the form of a white dwarf.

For a star that heavier than the sun but less than 3.5 solar masses, what happens is very different. When that critical iron level is reached, the star's outward radiation pressure can't hold up the upper layers of the star and the core collapses. This happens because the weight of the overlying matter is enough to 'break' the electron degeneracy and force the matter to collapse into a neutron degenerate matter. The core proceeds to collapse at 1/4 the speed of light under the pressure of hundreds of thousands of miles of overlying matter. Eventually, the inrushing matter hits the maximum density for a nuteron degenerate matter and can't compress anymore. The core then REBOUNDS...violently. The resulting shockwave is equivalent to the energy output of the rest of the galaxy for a few seconds and proceed to annihilate the outer layers of the star in what is commonly known as a supernova.

The remaining core is now known as a neutron star and is composed purely of neutrons. It is a neutron degenerate matter and cannot collapse any further because of the strength of neutron degenerate matter.

If the star was more than 3.5 solar masses or so, even ther strength of the neutron degenerate matter isnt enough. I'm not certain if it is still thought that a supernove happens in these cases. However, the collapsing core doesn't rebound - it just keeps collapsing forever. Eventually, the matter of the core, caught in its own upwardly spiralling gravitational field, is crushed into an infinitely small point known as a singularity.

At least, that's the theory. If there is some sort of stronger degenerate matter that we don't know of made of quarks or something (current theory says that there isn't), the core might stop at some smaller radius and not collapse into a singularity. Such a beast would look a lot like a black hole until you got really close and did careful observations. Eventually, there would be telltale things missing that would reveal that you aren't dealing with a true singularity. However, as I mentioned, no such stronger degenerate matter exists as far as we know and so we assume that singularities exist.

Phsicists would be happy if we could rule out singularities. The problem with singularities is that they break all our theories quite nicely. Most of the numbers in the equations either go to 0 or infinity, giving all sorts of nonsensical answers. It's more than I want to go into but there are serious issues with information theory and spacetime geometry that have some very relevant and troubling problems when applied to a singularity.

Now, what's this degenerate matter I keep talking about? Ordinary matter is basically almost entirely empty space. The reason that you don't fall through your almost non-existant floor is the Pauli exclusion principle. The exclusion principle states that no two fermions of the same quantum state can occupy the same energy level. A simplified version would be: no two electrons, protons or neutrons can be in the same place at the same time. Ordinary matter isn't ghostly because the electrons in their orbitals eat up quite a bit of space. Even though a single electron takes up a huge orbital, no other electron can go there. Electron degenerate matter is basically a form of matter where all the atoms have been squashed together so tightly that all of the available energy states are occupied by electrons so that there is no remaining free space. This known asa degenerate state and therefore, this matter is known as electron degenerate matter. It can't be compressd anymore because the electrons are packed as tightly as they can go. Therefore, a white dwarf ends up having a densiy about 1 million times a great as water.

If you push down hard enough, you start converting electron and protons into neutrons. This is a fairly complicated reaction that I won't go into. Anyway, larger star cores lose all their protons and electrons and end up as purely made of neutrons. The further collapse is possible because the electrons are now gone. Neutrons are also bound by the Pauli exclusion principle. Just like as above, the matter can't collapse as long as there are still neutrons present. Neutrons occupy a MUCH smaller volume and therefore neutron degenerate matter is much denser than electron degenerate matter - 500 million times denser, in fact. Although our understanding of how matter behaves at such densities is poor, we roughly estimate the density of this neutron degenerate matter or 'neutronium' to be about 5*10^14 or 500 trillion times the density of water.

The neutronium core is now a neutron star. In practice, neutron stars are much more intereseting to study than a black hole since they are so much more copmplex than a singularity. For example, the magnetic field around a young neutron star is so powerful that it will actually distort atomic nuclei and polarize light. These are magnetic fields billions of times more powerful and concentrated than anything we can produce in a lab. I'd highly recommend reading up on neutron stars - there's alot of really cool complexity and structure believed to be inside these things. I one even read a rather good sci-fi novel about a humans discovering a race of intelligent creatures made of atomic nuclei living on the surface ofa neutron star.

If you push even harder, the neutrons collaspe into something else through a process that I am not aware of. It may be know but I don't know it. At that point, as far as we know, it's a neverending fall to the infinity of a singularity.

Palomar · 2004-04-03 11:59:04

ecrasez - the coillision of two galactic-size black holes is something I dont even want to think about. The energy released from such an encounter is probably sufficient to wipe out most of the life in surrounding several galaxies.

*Astounding. Barring harm to other life forms of course, it would be beyond mind-boggling to behold (the things I wish I could witness!). It'd be akin (allowing for the vast differences in scale, of course) to the merger of two tornadic vortices, seems to me (based on my limited knowledge); just an analogy which came to mind (correct if wrong).

I will read your entire post (thanks!) again more thoroughly (pressed for time). I've also noticed an article online regarding the "shadow" of the Milky Way's SMBH; I'll read it again more carefully, and may link to it.

--Cindy

Palomar · 2004-04-08 07:47:02

Black holes or singularities are the end result of the collapse of a large star. ... What eventually happen is that iron builds up in the core. Iron is the most stable atomic nucleus so fusion of iron nuclei actually sucks up energy rather than generating it. Therefore, iron acts as a poison for the star. As iron concentrations go up, the process of the star's core getting hotter and denser keep going up until a critical point is reached.
For the sun and other smaller stars, what happens is that the star just dies and goes out. The outer layers are blasted off in a final moderate nova and the core is an electron degenerate matter. (a description of degenerate matters will follow) Since it's not dense and heavy enough to collapse the electron degenerate matter any further, the core just sits there and slowly cools off in the form of a white dwarf.
For a star that heavier than the sun but less than 3.5 solar masses, what happens is very different. When that critical iron level is reached, the star's outward radiation pressure can't hold up the upper layers of the star and the core collapses. This happens because the weight of the overlying matter is enough to 'break' the electron degeneracy and force the matter to collapse into a neutron degenerate matter. The core proceeds to collapse at 1/4 the speed of light under the pressure of hundreds of thousands of miles of overlying matter. Eventually, the inrushing matter hits the maximum density for a nuteron degenerate matter and can't compress anymore. The core then REBOUNDS...violently. The resulting shockwave is equivalent to the energy output of the rest of the galaxy for a few seconds and proceed to annihilate the outer layers of the star in what is commonly known as a supernova.
The remaining core is now known as a neutron star and is composed purely of neutrons. It is a neutron degenerate matter and cannot collapse any further because of the strength of neutron degenerate matter.
If the star was more than 3.5 solar masses or so, even ther strength of the neutron degenerate matter isnt enough. I'm not certain if it is still thought that a supernove happens in these cases. However, the collapsing core doesn't rebound - it just keeps collapsing forever. Eventually, the matter of the core, caught in its own upwardly spiralling gravitational field, is crushed into an infinitely small point known as a singularity.
At least, that's the theory. ...

*Thank you. I've re-read your post to this point (will re-read the remainder a bit later). I've previously (intermittently) read similar information, but your post is the best to date I've read.

You are speaking of stellar black holes.

It's incredible, all of it.

What about supermassive black holes?

This is getting to the point where I'm afraid I'll ask a dumb question... :-\

What is the genesis of a supermassive black hole? I mean, they're so huge...not due to 1 collapsed star (?). I'll check on Google, see if I can find something. I ask, because I'm under the impression (which could be very wrong, admitted) that they have different causes.

The differentiation between "stellar" black hole and "supermassive" black hole is a bit "new" (to me, at any rate)...I recall them simply being dubbed "black holes," period. Again, I'll see if I can find the answer myself on Google as well, of course.

More later.

--Cindy

Palomar · 2004-04-08 08:35:31

What is the genesis of a supermassive black hole? I mean, they're so huge...not due to 1 collapsed star (?). I'll check on Google, see if I can find something. I ask, because I'm under the impression (which could be very wrong, admitted) that they have different causes.

[http://www.xs4all.nl/~carlkop/bigb2.html]Click!

*I've said it before, will say it again: I love the internet!

That didn't take long.

"...Their thoughts turned to the formation of a supermassive black hole, at least thousands of times more massive than our sun. In recent years, giant black holes have been observed at the center of many galaxies, including our own Milky Way, and are believed to lie at the centers of extremely energetic quasars billions of light years away.

However, questions surrounding how these gargantuan black holes formed were as profound as the mystery of the gamma ray bursts. The theory proposed by the UCSD researchers, in effect, suggests a solution to both.

'We're suggesting that the events that give rise to distant energetic gamma bursts could also give rise to supermassive black holes in galaxies,' said Fuller.

According to the UCSD model, the genesis of a supermassive black hole could begin with the merger of hundreds of thousands or millions of stars drawn together by their own gravitational forces. As the coalescing and colliding stars interact with one another, matter is ripped away from the stellar surfaces until it settles into a single, unstable and short-lived super star, and/or produces a hot plasma of electrons and positrons. In either case, a tremendous amount of mass -- more than thousands of times that of the sun -- plunges through an 'event horizon.' A supermassive black hole is born..."

*Mind boggling critters!

--Cindy

::EDIT:: Article also mentions "Big Bang 2"

SBird · 2004-04-08 12:09:26

The link you posted is pretty similar to what I've seen myself. All black holes can gain mass dues to eating matter that comes too close. However, the supermassive ones at galactic centers clearly had a different way to gain all that mass. It probably has to do with both supermassive star formation in the early life of galaxies and the high star density that develops of galatic centers (lots of food).

Supermassive stars can have hundreds of times the mass of the sun. These get termed blue giants because their core runs so hot that the upper layers glow blue rather than red. IIRC, the core temperatures of the monster stars is in the hundreds of millions of degrees. These stars also go through their fusion fuel at a crazy rate. A huge star like Eta Carinae has a lifetime measured in the millions rather than billions of years. When these stars go up, it's a BIG explosion.

[http://hubblesite.org/newscenter/newsde … s/1996/23/]Here is a link to a picture of Eta Carinae. That nebula around it is due to a small hiccup it had. There is a fairly good possibility that it's already gone supernova and that the radiation is heading towards us. The scary part is that the energy is high enough to seriously jeapordize life on this planet. Although we'll probably be safe, there is the possibility that all life on the side of Earth facing that star gets fried.

The super stars posited to have existed in the early universe are posited to have masses thousands or millions times the mass of the sun. The death of these monsters would be equally stupidly big in magnitude.

The high energy gamma ray bursts that your article talk about have been a pretty big thing in astronomy for a couple years now. Up until a few years ago, it was assumed that they were just really powerful neutron star hiccups inside out own galaxy. However, more observations showed that they were actually coming from outside the galaxy, making them far more energetic. Then, they found that GRBs were associated with VERY distant galaxies which meant that the energy released in these events is just mind-blowing. These are definately galaxy-sterilizing events if not galaxy destroying events.

The only credible candidates are: supermassive black hole formation, colliding neutron stars and/or black holes or exotic physics such as cosmic string formation or spacetime defect collapse. Currently the hypernova/big black hole formation are in the lead since they can form powerful jets of energy. If one of these is pointed at Earth, the energy is much more concentrated, making the burst look more powerful than it actually is.

Palomar · 2004-04-14 13:18:39

[http://www.space.com/scienceastronomy/b … 40414.html]Runaway Star Collisions Create Black Holes

*A lot of speculation and controversy about "middle-weight" black holes. Speculation that perhaps "middle-weight" black holes may be "missing links" in supermassive black hole development.

The "When stars collide" segment is very interesting too. Discusses collision activity within dense star clusters, including this interesting tidbit: "Stars are not bombs, but rather smooth balls of gas," Portegies Zwart explains. "When two stars come very close they deform each other to droplet shape until they touch and merge. The merger itself is rather smooth too, and does not result in an explosion." Wow, they merge...

They mention one astronomer's caution that "the link between the ultraluminous X-ray sources detected by Chandra and intermediate-mass black holes is not yet conclusive." Also, gamma ray bursts.

Really good article.

[And I still must work through SBird's most recent reply...I *will* do that].

--Cindy

Palomar · 2004-04-21 10:21:10

[http://hubblesite.org/newscenter/newsde … s/1996/23/]Here is a link to a picture of Eta Carinae. That nebula around it is due to a small hiccup it had. There is a fairly good possibility that it's already gone supernova and that the radiation is heading towards us. The scary part is that the energy is high enough to seriously jeapordize life on this planet. Although we'll probably be safe, there is the possibility that all life on the side of Earth facing that star gets fried.
The super stars posited to have existed in the early universe are posited to have masses thousands or millions times the mass of the sun. The death of these monsters would be equally stupidly big in magnitude.
The high energy gamma ray bursts that your article talk about have been a pretty big thing in astronomy for a couple years now. Up until a few years ago, it was assumed that they were just really powerful neutron star hiccups inside out own galaxy. However, more observations showed that they were actually coming from outside the galaxy, making them far more energetic. Then, they found that GRBs were associated with VERY distant galaxies which meant that the energy released in these events is just mind-blowing. These are definately galaxy-sterilizing events if not galaxy destroying events.

*Hi SBird: Yes, I agree about Eta Carinae (fairly possible it's gone supernova already). Considering the time lapse. Thanks for the reminder (have read about it before).

Gamma rays...I need to brush up on those.

I've been wondering, if black holes (stellar and/or supermassive) are "for real" and each do possess a singularity, what happens to the two singularities if two BH's were to come together? Can they (the singularities of each) co-exist? Melt into one another? Repel one another? Is there any point in even wondering? ??? :laugh:

Also, we're so oriented to "up and down," "left and right"...but I'm presuming a black hole could theoretically develop in -any- conceivable direction?

--Cindy

SBird · 2004-04-24 01:00:45

Gamma rays are simply the most energetic form of Electromagnetic radiation (carried by photons). EM radiation goes radio, infrared, visible, UV, X-rays and gamma in order of increasing energy. Other forms of radiation like alpha, beta and cosmic rays are other sorts of subatomic particles that have rest mass. (helium nuclei, electrons and a various mix of particles make up those three previously mentioned) Gamma rays are very high energy, penetrate along way through matter (several feet of concrete are often not enough to stop them) and are moderately dangerous to get hit by.

As for what happens when two black holes merge, I'm pretty clueless. I vaguely remember reading that it would release a tremendous amount of energy but to be honest, I'm not certain how that would occur. The problem with black holes is that a lot of the stuff associated with them is very counterintuitive. (eg: hawking radiation, etc) You'd have to talk to a high energy physicist to get the lowdown here.

Palomar · 2004-05-06 20:11:56

*This evening I picked up the most recent issue of "Scientific American." In it is an article by famed cosmologist Gabriele Veneziano (as some folks have known longer than me -- string theory).

The article is "The Myth of the Beginning of Time."

He says that even just a decade ago, considering a time before the Big Bang was akin to asking directions to a place north of the North Pole.

I have a few questions about the following (summarizing in my own words, not quoting): He refers to Hawking and Roger Penrose, saying they proved in the 1960s that time can't extend backwrad indefinitely; as cosmic history is played backward in time all galaxies come together in a single infinitesimal point known as a -singularity.- He says it is almost like they were descending from a black hole; each galaxy or its precursor is squeezed down to zero size. Also, quantities like density, temperature and spacetime curvature become infinite.

I know the dictionary definition of the word "infinite." But I'm confused as to how he means that word in this context. Does it mean synonymous with "off the scale"? "Immeasurable"?

He goes on: (this is still Hawking and Penrose's ideas, I take it, which he's continuing to discuss) the singularity is an ultimate cataclysm which our cosmic ancestry can't extend beyond.

--Cindy

::EDIT:: For a long time I've considered universes existing prior to this one (and more to follow). Maybe a "rollover" of sorts from previous (and no longer active) religious conditioning. But the *time* issue is a bit difficult to grasp in connection with all this. :-\ Will keep reading...

Palomar · 2004-05-10 20:06:39

http://www.space.com/scienceastronomy/b … html]Thick dust around black hole

*Astronomers wondering how the supermassive black hole which "anchors" Galaxy NGC 1068 could be so thick. They're calling it a "torus of dust" (because it has a hole in the middle, rather than being a complete disc). It's about 11 light years across x 7 light-years thick.

Apparently it should be flatter, due to centrifugal force. Comparisons are the development of thin discs around stars (like the much-speculated-about Vulcanoids around Sol, I wonder??) and the rings of Saturn.

They say the dust torus' temp is "about room temperature" at its outer edge contrasted to 1,832 degrees F at the inner edge. Very interesting.

Also: "'The torus is composed of tiny dust particles similar to rock minerals on the Earth, including silicon, oxygen, and probably aluminum and magnesium,' Jaffe said."

--Cindy

SBird · 2004-05-12 10:37:47

Interestingly, one of the latest issues of Science was devoted to plsars and neutron stars. I was just reading an article about neutron star/black hole formation and its much more complex than I had realized. Once I've had a chance to digest the article a bit, I'll post an update to my earlier postings on this thread.

Palomar · 2004-05-12 12:35:04

Interestingly, one of the latest issues of Science was devoted to plsars and neutron stars. I was just reading an article about neutron star/black hole formation and its much more complex than I had realized. Once I've had a chance to digest the article a bit, I'll post an update to my earlier postings on this thread.

*Sounds interesting. I've often wondered what percentage of neutron stars are pulsars. I don't recall ever having seen an estimated percentage (whether via internet articles/resources or magazines, etc.). Perhaps I forgot.

--Cindy

::EDIT:: Ooooo, check it out (from Wikipedia): "Another class of neutron star, known as the magnetar, exists. These have a magnetic field of above 10 gigatesla, strong enough to wipe a credit card from the distance of the Sun away and strong enough to be fatal from the distance of the moon away. "

Yipes! Gigatesla...named after -the- Tesla? Will check Wikipedia for that...

SBird · 2004-05-12 22:34:43

Yep, Tesla finally did get some recognition and got a unit of magnetism named after him.

The magnetars have what is thought to be the strongest magnetic fields in the universe. Atomic nuclei are deformed from the magnetic fields and light is polarized. The highest magnetic fields we can generate before the magnets rip themselves apart is about 25 telsa.

The issue of Science has several articles about pulsars, in fact and one concentrates on magentars. It turns out that the magnetic field of these things is so powerful that it basically grinds the magnetar to a halt in a few decades. At that point, the magnetar basically becomes a dead neutron star that we can't see. If that's true, then the observed ratio between visible magnetars and pulsars suggests that magentars are actually the more common of the two.

Palomar · 2004-05-13 07:10:49

Yep, Tesla finally did get some recognition and got a unit of magnetism named after him.
The magnetars have what is thought to be the strongest magnetic fields in the universe. Atomic nuclei are deformed from the magnetic fields and light is polarized. The highest magnetic fields we can generate before the magnets rip themselves apart is about 25 telsa.
The issue of Science has several articles about pulsars, in fact and one concentrates on magentars. It turns out that the magnetic field of these things is so powerful that it basically grinds the magnetar to a halt in a few decades. At that point, the magnetar basically becomes a dead neutron star that we can't see. If that's true, then the observed ratio between visible magnetars and pulsars suggests that magentars are actually the more common of the two.

*Hmmmm. Wikipedia didn't have information on "gigatesla"; I was surprised. But then it was towards the end of the day, and I didn't have time to Google for it.

I'm going to have to get that issue of "Science." As indicated in my last post, I'm not overly familiar with magnetars.

I wonder what other funky stuff the Universe holds which we haven't yet discovered. ::shakes head:: If there is conscious, noncorporeal life after death, I'd love to take tour of the Universe...give me a couple million millenia at least.

--Cindy

::EDIT:: http://www.sciencedaily.com/releases/20 … 0312.htm]A good article on magnetars.

It makes sense that if a credit card would be wiped clean 93 million miles away from a magnetar, it'd definitely get wiped out from a mere 100,000 miles distance. But is the article in Wikipedia (my sig) correct with the "distance from the Sun" comparison? I suppose they vary, though, in size and intensity. I hope Wikipedia isn't overstating things... :hm:

SBird · 2004-05-15 01:07:03

Hmm, I'm no expert on the subject but being able to wipe a credit card at 1 AU seems a bit high. It takes a fairly intense magnetic field to do that and even an insane field would probably have dropped off to credit card safe distances aftera few hundred thousand miles.

BTW, a Tesla is the unit of magnetic strength, a gigatesla is just a billion of them - think 1.21 gigawatts to activate the flux capacitor.

Mark Friedenbach · 2004-05-15 13:00:28

well, the strength at 1AU would be about 11 milligauss, and the safty line for most research magnets (the line you wouldn't want to cross with credit cards or computer disks) is 5 gauss, about 440x what the magnetic field would be, so i think the author is exagerating a little bit (unless the field doesn't fall off as 1/r^2, but what kind of setup are we talking about then?). 11 milligauss is also about 45x less than the earth's magnetic field, as a comparison.

SBird · 2004-05-16 23:41:14

By that figuring, you'd have to be about 10 million miles away from the magnetar to worry about getting your cards wiped, still a pretty respectable figure. Imagine the kinds of science experiments you could do if you could get near one of those...

Palomar · 2004-05-25 10:44:15

By that figuring, you'd have to be about 10 million miles away from the magnetar to worry about getting your cards wiped, still a pretty respectable figure. Imagine the kinds of science experiments you could do if you could get near one of those...

*Yeah. :-\

http://www.spaceref.com/news/viewpr.htm … 272]Making black holes go 'round on the computer

*Cool article from spaceref.com. Computer simulation of binary black holes; one orbit and the simulation crashes.

They're working to be the first to "catch" a gravity wave rolling over the Earth (gravitational wave astronomy).

Hmmmmm. I wonder if there could be binary black holes "in real life"...wild and crazy universe out there after all (but then if the computer simulation of it crashes, I suppose not...). I don't recall reading about the possibility. :-\

--Cindy

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