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Fraser
2004-Sep-04, 04:20 PM
SUMMARY: Using the space-based XMM-Newton X-Ray observatory astronomers with the European Space Agency have made the first direct measurement of a neutron star's magnetic field. A neutron star is a very dense object with the mass of a large star packed into a radius of only 20-30 km, and they were predicted to have very strong magnetic fields which acted like a brake, slowing down their rotation. But after observing a neutron star called 1E1207.4-5209 for over 72 hours with the XMM, the astronomers discovered that it was 30 times weaker than they were predicting. What causes these objects to slow down is once again a mystery.

What do you think about this story? Post your comments below.

StarLab
2004-Sep-04, 11:31 PM
The field is weak probably because the charge is shifting, over time due to stress, from a generally neutral charge to a positive or negative charge.

om@umr.edu
2004-Sep-05, 04:23 AM
Thanks, Fraser, for the news.

I am pleased to see new measurements/observations on neutron stars. I suspect that a large fraction of the mass of the universe is tied up in such objects, perhaps at the core of many so-called ordinary stars.

I recall once quoting a value from Tommy Gold of 10^12 gauss for a newly formed neutron star.

Probably spin and magnetic fields of neutron stars go together.

Oliver
http://www.umr.edu/~om

om@umr.edu
2004-Sep-06, 09:46 PM
If the Sun's magnetic fields arise from its deep interior, one should be able to set limits on the strength of the magnetic fields at its core.

With kind regards,

Oliver
http://www.umr.edu/~om

PS - Does anyone have a link for the Full Story on the neutron star measurement?

VanderL
2004-Sep-07, 04:42 PM
Hi Oliver,

Be aware that once in awhile the UT story comments section gets a "blast" of a number of older news items, apparently a glitch that isn't easy to repare. This news is a year old and the original news item is here http://www.esa.int/export/esaCP/SEM1E0T1VE...ED_index_0.html (http://www.esa.int/export/esaCP/SEM1E0T1VED_index_0.html)

Cheers.

om@umr.edu
2004-Sep-07, 05:28 PM
Thanks, VanderL.

I found no value for the measured value of the magnetic field.

Only the statement that it was 30 times weaker than predicted.

And this intriguing statement about the forces that decelerate spinning neutron stars:

"We can only speculate that it may be a small disc of supernova debris surrounding the neutron star, creating an additional drag factor."

With kind regards,

Oliver
http://www.umr.edu/~om

VanderL
2004-Sep-07, 07:12 PM
Hi Oliver,

I wouldn't be surprised that, when our telescopes finally have the necessary resolution and really image a neutron star, it turns out to be a star that isn't spinning like mad. Just an ordinary sphere which is part of an oscillating circuit making it look like a sort of stroboscope. Our Sun is a slow oscillator, only once every 11 years.

And a magnetic field 30 times weaker than predicted? I'm sure it is either deemed unimportant for the theory or we likely won't hear from it again until some smart scientist comes up with a solution that still fits the model.

This reminds me of an earlier discussion where it was found that a certain star (Achernar) was at least 50 % flatter at the poles than at the equator. I mentioned then (almost a year ago) that we probably wouldn't hear from this surprising observation again until someone comes up with an explanation that still fits the Standard Model. If it isn't possible to make it conform to the Standard Model we most likely won't hear from it again.



And this intriguing statement about the forces that decelerate spinning neutron stars:

"We can only speculate that it may be a small disc of supernova debris surrounding the neutron star, creating an additional drag factor."

Now there's something useful for your model, the debris that possibly falls back unto the SN core to form a new kind of star.

Btw in the EU model a supernova event is the moment where either a large planet, a brown dwarf or a new star is born, in the process creating some new debris to form smaller (rocky?) planets.


Cheers.

Duane
2004-Sep-07, 08:57 PM
VanderL you have been shown time and again that the EU model of the universe is flawed. By the way you cling to this theory I would suspect you have some investment in seeing its agenda pursued.

You have said that you keep an open mind. You have been shown many reasons why the theory is not well accepted by the mainstream of science--not because it is "radical" VanderL, but because it does not work.

So I ask you now--what evidence would you accept to be able to state that the theory is incorrect?

As to this story, and to return to topic, not all that long ago they found a SNR that displayed magnetic fields a thousand times stronger than expected. Neither of these two things will upset the SSM much--the basics and foundation of the theory are sound and well documented both observationally and experimentally.

What these findings do is allow us to tweak the edges of the theory, to deal with very exotic objects that are at the very cusp of our understanding of the universe and the obejects that make it up.

Furthermore, the magnetic fields of neutron stars have been measured directly VanderL.

As for Achernar, I believe Tim Thompson dealt with that in a thread previously. Ah, yes:
QUOTE
V: I'm still waiting for the current theories to find a patch to stop this gap. F: Yes, conventional physics can only account for a 20-30% bulge.



The first statement is misleading, and the second is just wrong. The reality is that Achernar is a Be class star (a spectral B class star with photospheric emission lines), which is one of the more exotic & peculiar types of star (see Classical Be Stars, J.M. Porter & T. Rivinius, Publications of the Astronomical Society of the Pacific 115: 1153-1170, October, 2003 for a detailed examination of the peculiarities). The models for Be stars, such as they are, amount to no more than 1st approximations, primarily because the physical details are too complicated to deal with. As de Souza, et al., point out in their paper from September (The spinning-top Be star Achernar from VLTI-VINCI, de Souza, et al., Astronomy and Astrophysics 407: L47-L50, September 2003), their optical model is based on a uniformly bright disk (which we already know is not really correct), and the internal physics models assume uniform rotation, which is probably also not physically real. They also do not include convection or internal turbulance. The models are incomplete approximations, so it is hardly surprising that they don't properly anticipate the observed shape of the star. This also means that no one can say that "conventional physics" does not account for the full oblateness of the star, since in reality, no one has really tried to use conventional physics on the problem yet. When they try, and fail, then we can make such a claim.

There is a lot of physics to worry about here. For instance, if the internal rotation of the star is not uniform, if it is faster towards the center of the star, then we know that the star will bulge more at the equator than would a uniformly rotating star (which would lead the models in the direction of this observation). There is also the open question of the affect of magnetic fields on the stellar bulge (stronger than "normal" magnetic fields may well be "normal" for Be stars; I think only one Be star magnetic field has been measured, and it is unusually high). And what about the affect on observations of a circumstellar gas shell? De Souza, et al., believe that their observations and implied flattening are not contaminated by a gas shell, since they don't see excess H-alpha emission, but there might still be a systematic bias in the flattening observation. And, there might also be a physical consequence of mass loss, in the equatorial bulge. In short, there is a lot of work to do before one can make definitive statements, one way or the other.

The real interest here is that the observation of the oblateness of Achernar is a first of its kind observation. It's not always possible to derive a complete physical picture of something from "first principles". We can't simply derive a realistic stellar model from scratch, because there are too many free choices to make. Rather, we need to calibrate the models against real observations. That constrains the choices, and allows the modelers to more quickly zero in on what works and what doesn't. Until now, no one has known enough about real Be stars to make detailed physical models. Now we know a lot about at least one Be star, and that's one more than we had. Now we can get down to the business of deciding which details are important, and which aren't, in modeling this kind of star. And, the more observations like this we get, the better off the modelers will be. Give them a few years, and we'll have much more realistic models of a Be star interior, and a much better understanding of the detailed physics. That's the real fun part.

VanderL if it doesn't fit the standard model, it most assuredly does not mean that it is somehow ignorred or forgotten. (Are you a conspiracist? Just because you're paranoid doesn't mean no one is watching you!) On the contrary, the most exciting discoveries are those that do not fit as expected. That is the drive of a scientist--explain why it doesn't fit and/or what the cause of the discrepancy is. That is how the SSM has evolved over the last 100 years--observe, measure, adjust, observe and measure again.

That is why the EU model doesn't work either VanderL--the underpinnings of the theory do not measure up to observations.

Finally, with regard to the debris disc around the neutron star, if it is falling onto the surface of the NS, it is being crushed flat by the highest gravity field outside of a black hole. (Oh yea, you don't believe in those either :D ) If enough material collects, it will explode. It will not collect into a shining star with planets, regardless of what Doc M says. It cannot happen that way!

Skepticism is a good thing VanderL. I would only add the suggestion that you try to apply it evenly in both directions--something the bulk of your posts do not convey.

om@umr.edu
2004-Sep-08, 01:28 PM
Originally posted by Duane@Sep 7 2004, 08:57 PM
Finally, with regard to the debris disc around the neutron star, if it is falling onto the surface of the NS,

[1.] it is being crushed flat by the highest gravity field outside of a black hole. (Oh yea, you don't believe in those either :D )

[2.] If enough material collects, it will explode.

[3.] It will not collect into a shining star with planets, regardless of what Doc M says.

[4.] It cannot happen that way!
Duane -

Are these personal opinions?

Did you make the measurements or observations?

You seem more certain than any scientist I know.

Please. Quote from scientists studying neutron stars.

With kind regards,

Oliver
http://www.umr.edu/~om

Mild mannered
2004-Sep-08, 02:11 PM
Ulp

Well here goes a really, really stupid question I suppose - I will brace my ego and squnit through my fingers at the replies...

Q: to do with super dense, exotic objects like Neuron stars / black holes I've always thought that the more massive they are the faster they spin - indeed that there were simple equations to work out rates of spin/mass/size all from each other - I think Kip Thorne said there are only three thing I need to know about a black hole to determine everything else and they were the parameters.

So More massive - greater spin. But if Neuron stars spin slower than we thought doesn't that throw off the calculations and should we look at black holes differently?

Also could part of the reason be due (and this is the really stupid part of the question) to the thickening (condensing) of space - time in the vicinity of these objects? I know we get gravity drag what about space-time drag?

Mild (and posibly stupid) :blink:

Duane
2004-Sep-08, 02:13 PM
You seem more certain than any scientist I know.

Please. Quote from scientists studying neutron stars

I have. Shame you won't take the time to read the research I have cited. You are quick to arrogantly dismiss anything that does not meet with your personal views of what is. The fact that we have provided a plethora of research showing that your theory is likely incorrect seems to have brought out the beast in you Dr Manuel.

I once believed that you had something to offer. I am deeply saddened to discover I was wrong.

Mild mannered
2004-Sep-08, 02:22 PM
Help! I seem to be in the middle of two Galaxies tearing themselves apart - agh...
Easy guys :o
Mild (possibly stupid) and wearing a tin hat! :D

Duane
2004-Sep-08, 02:29 PM
to do with super dense, exotic objects like Neuron stars / black holes I've always thought that the more massive they are the faster they spin -

Not a stupid question at all Mild! :)

The spin of a massive object is predicated on a number of things, mass being one of them. A very massive object stuffed into a small space (such as a neutron star) will pick up spin as a function of conservation of angular momentum. It is similar to a figure skater in a spin--when the arms are pulled in, the skater picks up speed.

Spin rates of a neutron star (NS) can also be imparted by the accumulation of mass from a companion. Many of the millisecond pulsars appear to have "spun up" in this manner. The mechanism is essentially the same--the mass can't all land on the smaller massive object at the same time, so it goes into orbit around it. This imparts further angular momentum onto the smaller object, causing the object to pick up speed.

Magnetic fields also seem to play a big role in this, although exactly how is not well understood. It is thought that the material streaming onto the NS is confined by the magnetic field lines, such that it is forced to accumulate onto the surface at the points where the field lines intersect the main body. The material can overwhelm this area, which seems to account for the bi-polar jets seen around some of these objects.

So, to short answer the question, mass is only one of several factors that determine the spin rate of a massive object.

Mild mannered
2004-Sep-08, 02:38 PM
Thanks Duane

Sorry about the Tin hat gag - with the other story comment on galaxies being torn apart and you bigger guys being Galaxies an' all I couldn't resist! :D

on the Bi-polar jets I read another article/book some damn hting about quasars and possible explanations about how black holes might cause them (the mechanism) - the one that sort of lurks in mind was to do with magnetic field lines at the poles spinning (and super heating) gas into vortexes - but hey this was eons ago.

Is this related to your bipolar jets - the quasar thingy?

Mild (Not quite as stupid as he thought!) but losing his memory these days

PS: what about space-time drag - is this a factor in spin rates?

Duane
2004-Sep-08, 03:11 PM
Mild, you are mixing up a couple of different things in your questions.

Regarding the jets around quasars, the mechanism that is causing them is not well understood. Current thinking is that magnetic fields play an important role, similar to what you see on neutron stars and newly formed stars. Certainly it seems that the magnetic field lines around these objects is twisted and highly distorted--but again, the mechanism is not well understood.

Space-time drag is a relativistic term relating to the affect a massive object has on the space around it. This is what the Gravity Probe-B spacecraft is going to try and measure.

om@umr.edu
2004-Sep-08, 03:46 PM
Originally posted by Duane@Sep 8 2004, 02:13 PM

You seem more certain than any scientist I know.

Please. Quote from scientists studying neutron stars

The fact that we have provided a plethora of research showing that your theory is likely incorrect seems to have brought out the beast in you Dr Manuel.

This thread is not about "my theory."

The question is whether you have evidence to support your dogmatic statements:

"Finally, with regard to the debris disc around the neutron star, if it is falling onto the surface of the NS,

[1.] it is being crushed flat by the highest gravity field outside of a black hole. (Oh yea, you don't believe in those either )

[2.] If enough material collects, it will explode.

[3.] It will not collect into a shining star with planets, regardless of what Doc M says.

[4.] It cannot happen that way!

Of course you don't. Scientists don't make such statements.

Oliver
http://www.umr.edu/~om

VanderL
2004-Sep-08, 03:47 PM
VanderL you have been shown time and again that the EU model of the universe is flawed. By the way you cling to this theory I would suspect you have some investment in seeing its agenda pursued.

You have said that you keep an open mind. You have been shown many reasons why the theory is not well accepted by the mainstream of science--not because it is "radical" VanderL, but because it does not work.

So I ask you now--what evidence would you accept to be able to state that the theory is incorrect?


Duane, I'm sure you have all the answers, but I'm a firm believer in seeing before believing. So if I think the EU model has merit, I'll stick to that idea until I "see" it disproven and not because someone tells me. It is true that new ideas are often ignored and ridiculed even if they do have merit, so I'm not impressed by someone (not even Tim) telling me it doesn't work. I hope I made it clear why I think it has merit, you can disagree, but please don't tell me what to think or believe.

And don't start insinuating a hidden agenda or paranoid behaviour; I didn't join this forum to have my motives questioned. Frankly, if you feel I'm stepping over boundaries and if you think I should stop posting, please tell me so, and if not don't harrass me.

Until now I liked the relaxed atmosphere in this forum, but I have the feeling you're trying to shut me up.

Cheers.

Duane
2004-Sep-08, 04:23 PM
**Sigh** VanderL, I am sorry and I am disappointed. You see something about EU in most of the topics you visit. I am not trying to shut you up; on the contrary I am asking you to display some of the even-handedness you have asked us to display when talking about this subject. I have never asked you to believe or think anything.

Whether the idea has merit or not is not the issue here. Nor have I done anything to "harass" you. I responded to your comment that someone somewhere was suppressing evidence for some apparently nefarious purpose. I meant it in a humorous way VanderL, I had thought you would see that.

If I felt you crossed a line, I would tell you. Might I point out to you that you have been jumping all over me over my disagreements with Doc Oliver's methods and conclusions, even going so far as to suggest I was somehow aiming my comments at you. Don't flatter yourself VanderL, I didn't even consider you when I made those comments. Frankly, I thought you were much smarter than that.

As for you Doc O, shake your head, your eyes are stuck. The evidence has been laid out clearly in the iron sun discussion, and your insults and insinuations mean nothing to me. You think you can bowl me over because you have some hoity toity symbols behind your name, but I am not intimidated. I have invited you to debate the issues several times, yet all you do is repost the same old tired mantra. Read the research we have provided and point out the flaws, if you think them so wrong.

The statements I made are based on the research I have located, and I stand by them. I did not direct my comment to you, and could care less whether or not you responded to it. I say to you again, if you think the statements are wrong then feel free to provide evidence disputing them.

Of course you won't do that, because you have nothing to back it up. Your dogmatic, unyielding stance serves no one. Fire at will Doc, I'm laughing at you.

Mild mannered
2004-Sep-08, 05:14 PM
Thanks Duane

I agree they are poorly understood - certainly by me!

Sorry for mixing questions and all - just thinking outloud

Cheers
Mild :D

Duane
2004-Sep-08, 05:26 PM
No problem Mild, it's fun to seek answers and opinions. Not everything we think we know now will remain "right" and some things we think are wrong will come out on top. Key is to keep on asking--just keep a healthy dose of salt handy.

om@umr.edu
2004-Sep-08, 05:43 PM
Originally posted by VanderL@Sep 8 2004, 03:47 PM
And don't start insinuating a hidden agenda or paranoid behaviour; I didn't join this forum to have my motives questioned.
I agree with you VanderL.

Tactics like Questioning others motives

or insinuating a hidden agenda

or some paranoid behaviour

has no place in science.

Nor does dogmatic certainity.

Hang in there! Don't let Duane drive you away.

The quality of UT will decline if Duane succeeds.

Stay and help Duane clean up his act.

With kind regards,

Oliver
http://www.umr.edu/~om

StarLab
2004-Sep-08, 05:52 PM
If this argumentation continues any further in this string or any other, I'm going to ask Fraser to force you to have all your arguments via PM. :angry:

VanderL
2004-Sep-08, 08:30 PM
If this argumentation continues any further in this string or any other, I'm going to ask Fraser to force you to have all your arguments via PM.

Agreed Starlab, you're right. Sorry I reacted this way, this is a little out of character for me, won't happen again in a thread.
Oliver thanks for the support.

Cheers.

Guest
2004-Sep-29, 12:45 AM
Hello im having some trouble with my homework and if someone could help it would be good... the question is "What is the relationship between distance from the ridge and age of oceanic crust" please help!!

Tinaa
2004-Sep-29, 02:42 AM
I'll give you a hint. Think of a graph with the x-axis as time and the y-axis as distance. If the ridge is zero and a line has a slope of 1/2 what have you got?