Artist's impression of an anomalous X-ray pulsar. Credit:  ESA
Artist's impression of an anomalous X-ray pulsar. Credit: ESA

Astronomy, Science

Faster-Than-Light Pulsar Phenomena

6 Jan , 2010 by

Observational data from nine pulsars, including the Crab pulsar, suggest these rapidly spinning neutron stars emit the electromagnetic equivalent of a sonic boom, and a model created to understand this phenomenon shows that the source of the emissions could be traveling faster than the speed of light. Researchers say as the polarization currents in these emissions are whipped around with a mechanism likened to a synchrotron, the sources could be traveling up to six times light speed, or 1.8 million km per second. However, although the source of the radiation exceeds the speed of light, the emitted radiation travels at normal light speed once it leaves the source. “This is not science fiction, and no laws of physics were broken in this model,” said John Singleton of Los Alamos National Laboratory at a press briefing at the American Astronomical Society meeting in Washington, DC. “And Einstein’s theory of Special Relativity is not violated.”

This model, called the superluminal model of pulsars, was described by Singleton and colleague Andrea Schmidt as solving many unanswered issues about pulsars.”We can account for a number of probabilities with this model,” said Singleton, “and there is a huge amount of observational data available, so there will be ample opportunities to verify this.”

Pulsars emit amazingly regular, short bursts of radio waves. Within the emissions from the pulses, the circulating polarization currents move in a circular orbit, and its emitted radiation is analogous to that of electron synchrotron facilities used to produce radiation from the far-infrared to X-ray for experiments in biology and other subjects. In other words, the pulsar is a very broadband source of radiation.

However, Singleton said, the fact that the source moves faster than the speed of light results in a flux that oscillates as a function of frequency. “Despite the large speed of the polarization current itself, the small displacements of the charged particles that make it up means that their velocities remain slower than light,” he said.

These superluminal polarization currents are disturbances in the pulsar’s plasma atmosphere in which oppositely-charged particles are displaced by small amounts in opposite directions; they are induced by the neutron star’s rotating magnetic field. This creates the electromagnetic equivalent of a sonic boom from accelerating supersonic aircraft. Just as the “boom” can be very loud a long way from the aircraft, the analogous signals from the pulsar remain intense over very long distances.

Rapid condensation of water vapor due to a sonic shock produced at sub-sonic speed creates a vapor cone (known as a Prandtl–Glauert singularity), which can be seen with the naked eye.

Back in the 1980s, Nobel laureate Vitaly Ginzburg and colleagues showed that such faster than light polarization currents will act as sources of electromagnetic radiation. Since then, the theory has been developed by Houshang Ardavan of Cambridge University, UK, and several ground-based demonstrations of the principle have been carried out in the United Kingdom, Russia and the USA. So far, polarization currents traveling at up to six times the speed of light have been demonstrated to emit tightly-focused bursts of radiation by the ground-based experiments.

Although Singleton and Schmidt’s highly technical presentation was admittedly over the heads of many in attendance (and watching online), LANL researchers said the superluminal model fits data from the Crab pulsar and eight other pulsars, spanning electromagnetic frequencies from the radio to X-rays. In each case, the superluminal model accounted for the entire data set over 16 orders of magnitude of frequency with essentially only two adjustable parameters. In contrast to previous attempts, where several disparate models have been used to fit small frequency ranges of pulsar spectra, Schmidt said that a single emission process can account for the whole of the pulsar’s spectrum.

“We think we can explain all observational data using this method,” Singleton said.

When asked, Singleton said they have received some hostile reactions to their model from the pulsar community, but that many others have been “charitably disposed because it explains a lot of their data.”

Lead image caption: Artist’s impression of an anomalous X-ray pulsar. Credit: ESA

Papers: Singleton et al,, Ardavan, et al, Ardavan, et al
Sources: AAS press conference, LANL,

By  -        
Nancy Atkinson is currently Universe Today's Contributing Editor. Previously she served as UT's Senior Editor and lead writer, and has worked with Astronomy Cast and 365 Days of Astronomy. Nancy is also a NASA/JPL Solar System Ambassador.



37 Responses

  1. SuperKevin says:

    A great discovery, were starting to bend the rules. Hope research into this continues.

  2. Torbjorn Larsson OM says:

    No rules were bend in making this phenomena. Or at least, that is what the article takes great care to explain.

    However, I must confess that I have trouble visualizing the geometry. That linear globally superluminal “polarization rail guns” or ratchets emits radiation in lobes is something I have had reason to dig into before though. (Popular among superluminal crackpots that thinks they break relativity any more than a light spot moving superluminal on a distant surface.)

    I just never thought they applied to any natural phenomena, even less the fantastically focused fans of pulsar radiation. 16 order of magnitude? 2 parameters? That is some predictivity!

  3. Lawrence B. Crowell says:

    The superluminous velocity is similar to a group velocity, which can be faster than light for a single particle or photon. Two charged species in an ionized gas can have charged waves, a sort of group velocity for currents, which can propagate faster than light. Another way to think of this, it is a bit like the “wave” in a stadium crowd, where the wave can move much faster than the speed each person moved up or down. Since the individual species do not travel faster than light there are no causality violations.

    LC

  4. Hannes says:

    I wonder, do they mean transverse waves and their “photons” are restricted to lightspeed and longitudinal “wavelike structures” can have superluminal speeds?

    Do they mean that the existing longitudinal wave can can propagate faster than light but the parts (photons) are limited to luminal speed?

    This is only possible in an already standing wave. Only that way the “wave” exhibits superluminal behaviour.

  5. Torbjorn Larsson OM says:

    @ Lawrence:

    How do you define a group velocity for a single photon?

    [Also, I come up with references that for example single photon “group velocity” superluminal tunneling is the cavity lifetime to empty the barrier. [quant-ph/0601085]. Of course, I haven’t had time to study them.]

    The rest are fine examples of global (collective) superluminal phenomena, btw.

    @ Hannes:

    Yeah… I forgot that, the resulting lobes (and here jets) should be essentially non-radiative, that was as far as I got last time on this. (But they can be moved around, of course.)

    I never got around to see how they radiate in the far field. Um, starting to have some “hostile reactions” now. 😀 (Of course, this time I have some fair sources to study.)

  6. Torbjorn Larsson OM says:

    @ Lawrence:

    Oh, duh, strike that! The problem I was thinking of is that the wave packet group velocity _is_ the particle velocity. The rest applies, how does a single photon go superluminal?

  7. William928 says:

    @LBC: A single photon or particle moving faster than the speed of light perhaps, but 6 times C? I’ll assume they’re simply guessing here…

  8. Lawrence B. Crowell says:

    I write this with a bit of hesitancy, but here goes. The velocity of a wave is determined by the index of refraction n, and the phase velocity (velocity of the actual wave front) is v_p = c/n, where here I am assuming photons. The index of refraction from the group velocity is

    n_g = n + f(&n/&f), & = partial symbol

    for f a frequency. The group velocity is then v_g = c/n_g. So this involves the velocity of Fourier modes, which can be much higher than the speed of light.

    I said hesitancy, for I am suddenly being dogged by Aodhhan where on the post about pulsars as gravity wave detectors I mentioned the weakness of a gravity wave. This guy came bursting forth with insults and rants. I have no idea what prompted this, and I see nothing wrong with what I wrote particularly. He has pulled this on other blog areas here. You can check that out at:

    http://www.universetoday.com/2010/01/05/new-pulsar-clocks-will-aid-gravitational-wave-detection/

    and I would be interested to know if this guy, who I suspect is using a sock puppet, is at all right or justified in this nonsense. I use my real name, and I wonder if this guy is somebody I know or knew who has some enmity against me. It is somewhat unnerving.

    LC

  9. damian says:

    Cool, so someone had to ask.
    How do we strap a Pulsar to a spaceship? :)

    Of course, the stream of energy that actually emerges only comes out at light speed. So the best you could do is accelerate to the speed of light.

    But understanding that its possible in nature, (even theoretically) does open the imagination to such contemplation.

    Gravity…. damn you for hiding your secrets.

    Damian

  10. Aodhhan says:

    Alright LC… I will give you the benefit of the doubt.

    Explain to me why you chose to post the formula you did, and also explain what it has to do with the faster than light pulsar phenomena.
    Because all I see, is a random formula you chose… which anyone can look up. Nowhere have you talked about what it has to do with the subject at hand.

  11. Lawrence B. Crowell says:

    The equation comes from Fourier analysis. The group velocity then depends upon the dispersive term &n/&f, which can give a faster group velocity.

    This is an example based on a photon or EM wave. In this case the wave is a type of plasma wave, or maybe a propagating Alfven wave. I am not very learned in plasma physics, a bit but not much, so I can’t go into great depth there. Which ever the case, the plasma wave has dispersive properties which permit a group velocity to be larger than the speed of light.

    Now here is a problem. These are brief blog postings, not extensive papers for review. So I am not going to write in a TeX-ified manner all sorts of equations here. That is why I just write the n_g according to the dispersive term and avoid going into much detail. Further this is not TeX enabled and does not support unicode, so reading equations is unpleasant. So as rule here, with a few exceptions, I tend to keep answers brief, but which touch on some of the basic physics involved. If people are interested it might be something they can use to read about this in greater detail elsewhere.

    LC

  12. Aodhhan says:

    So it is like I stated before.

    It is something which you think has something to do with this subject.
    It may if correctly explained, be able to correlate with part of the subject… that being superluminal properties. However, with the information you displayed. It would take some explaining…. which wasn’t done. I.e. bring together the similarities of each, along with any deltas….and you would definitely have to have a really good understanding of the subject at hand, along with a really good understanding of general relativity and particle acclerators… otherwise you won’t understand why this doesn’t break Einsteins theories… basically that nothing can go faster than the speed of light.

    For the person wanting to know my credentials. This is the Internet, where you can be anyone you want… if I listed my information… you wouldn’t beleive it. Also, from participating in other informational informal blogs where I’ve used my real name.. I’ve learned my life is alot easier when I’m anonymous.

  13. Olaf says:

    @Aodhhan, so far you have not shown anything about any credentials. So far I see a list of scientific words you use but stay fuzzy. You still might be a quack pretending to be someone big and intelligent.

    So please show us how to visualize this faster than light speed without using those fuzzy words.

  14. Olaf says:

    @Aodhhan what exactly is wrong with LBC his formula?

    His explanation is exactly on topic.

  15. Lawrence B. Crowell says:

    @Aodhhan: Somebody asked about photons, so I used that as an example. The physics here involves dispersion, which is a generic property of wave mechanics in media. It works much the same for light as it does for plasma waves. Besides this is a brief blog post, not a treatise on plasma physics.

    Anyway, to be honest if you really think you have a better way of presenting this, or can add to it, be my guest. That would be preferrable to you makiing these negative statements which contribute nothing to the matter at hand.

    From what I can see you appear to be a troll. You really contribute nothing, but sound off as if you are something special. Well if so then say something relevant here. Put up or shut up.

    LC

  16. Torbjorn Larsson OM says:

    @ LBC:

    this involves the velocity of Fourier modes, which can be much higher than the speed of light.

    Ah, so you are referring to the wave packet shape, not the wave packet (photon). Right!

    If I remember the outcome of this correctly, the conclusion was that you had to conclude that the front of the finite length packet shape was the information carrier. As that can’t pass the phase velocity of a finite packet, the information won’t go faster than light (and thus protect relativity), and in a very general sense the wave packet (photon) won’t either.

    I guess I should read the reference I gave, but it doesn’t seem too useful at this point. I do think we agree on the physics, albeit perhaps not how to describe it. :-)

    [Btw, as for the other thread, LBC is in the right there as well.]

  17. Lawrence B. Crowell says:

    Exactly. You can think of the center of the wave packet as the phase front, which for a photon can only travel v = c/n, but the wave packet can spread so various modes reach stupendous velocities. The velocity of the center of the wave packet, think of it as the mean (or the quantum probability velocity or momentum) is limited by relativity.

    LC

  18. Aodhhan says:

    I will simplify this down to about a 9th grade level.

    If you imagine this entire system as a wheel, and at the hub of the wheel is the millisecond pulsar, traveling near the speed of light. Think of the radio waves as the curved spokes of the entire system. As they move towards the end of the wheel they are accelerated. Induced by the magnetic waves, they collect to become the outside circumfrance of the wheel.

    So if the pulsar is the hub, moving near the speed of light, the end of the wheel will be moving much faster. In excess of the speed of light.
    Since it is commonly known… on a wheel, the outside edge is moving much faster, with the same amount of force than the hub providing the energy.

    I left out the explanation about polarization, the need for a perfect vacuum, and a few other things.. but in a simplified version… this is what is going on without breaking the laws of general relativity.

    You don’t need to use 50 dollar words, when words costing a dime will work.

    I really don’t care if you think I’m a quack or not. One thing is for sure… anything I post is my work, not words cut and pasted from a searched site, or something poorly paraphrased from some site, where the work is done by someone else. Anything I post is well written and easily understood.

  19. LC, just don’t worry about it.

    You can spend eternity looking for what you did to piss him off… Just put up an imaginary ad blocker, I’m sure you’ve got better things to do, and I’m coming to the opinion that he doesn’t…

  20. Lawrence B. Crowell says:

    Yeah, it is clear that this guy is talking hogwash and seems to have a minimal understanding of physics. No Aodhhan, I don’t paste this in from other web sites. I know this level of physics better than I know the back of my hand, and tap out some of the longer posts I write in five to ten minuites.

    LC

  21. ND says:

    Aodhhan: “if I listed my information… you wouldn’t beleive it.”

    Interesting you says this. Why would we not believe you when you list your credentials? This does not appear to be an issue with most people that post here. The problem is your belligerent tone. You seem to have a chip on your shoulder.

  22. Olaf says:

    I found this simulation on the internet:

    http://www.physics.purdue.edu/MOJAVE/superluminal.swf

    Interesting to see ho stuff appears to move faster than light but in reality never moved faster.

  23. Olaf says:

    @Aodhhan

    “So if the pulsar is the hub, moving near the speed of light, the end of the wheel will be moving much faster. In excess of the speed of light.
    Since it is commonly known… on a wheel, the outside edge is moving much faster, with the same amount of force than the hub providing the energy.”

    Your explanation is confusing, here you clam that the pulsar is moving at the speed of light. This is not what the article tells us.

    Also your explanation violates the speed of light at the end of the wheel. It does not conform to what the article explains.

    Your explanation is as silly as saying that if you travel at light-speed and shine a light towards your direction it doubles the speed of light.

    This part in the text “the sources could be traveling up to six times light speed, ” is a bit misleading.

  24. Lawrence B. Crowell says:

    Olaf, this is similar but different. This is an apparent superluminal velocity due to an angular effect.

    I am a bit curious as to why this Aodhhan fellow has taken such an emnity towards me. It gives me a slight errie feeling this guy is somebody I know or knew in the past and has some long standing grudge. Why target me exclusively with this pile of hogwash? Yet it is clear Aodhhan would fail a sophmore level exam in electromagnetism or mechanics. I suppose I should just blow him off at this point.

    LC

  25. Olaf says:

    I just found another demonstration of superluminal motion.

    http://gregegan.customer.netspace.net.au/APPLETS/20/20.html

  26. Olaf says:

    Yes LBC you used the magic word “apparent”.
    Aodhhan his description did not.

    The sources themselves do not move faster than the speed of light but the appear to be moving faster than light.

    One way to visualize this is you have a series of lights. All connected to some electronics with equal length of wiring. You program it or create a running light. So you see the lights move front the start to the end. Now speed this up so fast that the first light appears to reach the end of the series faster than light. This can be perfectly done since you trigger the light at the electronics and they have to travel the same length of wire not violating the speed of light but once reached the light the series of appears to be triggered faster than the speed of light provide you put a very tine picosecond or lower delay for each light trigger.

  27. Lawrence B. Crowell says:

    There is a little detail section in Egan’s (I know this guy a bit) which gives a quick calculation of this. In a sense these are all an example of angles or phases. A beach wave might reach the shore at a slight angle and the pont where the crash happens will move along the shore much faster than the wave is moving.

    LC

  28. Olaf says:

    Another example I heard was the movement of a caterpillar. While the legs itself did not violate the speed of light the body movement appears to exceed speed of light. LOL

    Or in human words: The body of the caterpilar appear to move faster than its legs.

    No harm was done to any caterpilla. LOL

  29. Olaf says:

    There is one thing that I can’t get a complete grasp of the article. The sources are triggered in a sequence that appears top be faster than the speed of light. And it is possible because of the rotating magnetic field.

    These sources are in the pulsar his surface, so the fast rotating magnetic field triggers the sources just like in my running light explanation. The sources do not move by themselves or not much so no violation of the speed of light. But because you have so many sources in the surface and is triggered as a running light, it appears to be on single source that moves around the surface of the pulsar faster than light-speed.

  30. Lawrence B. Crowell says:

    I will first confess I am not deeply educated in plasma physics. Yet there is a wave which propagates along the plasma which induces a charge separation. This would be something like an Alfen wave. This then makes the charge source for this radiation move on a group velocity that is very rapid. Yet this happens without any actual charged particles moving faster than light.

    LC

  31. Olaf says:

    I think I have the picture now. The sources are atoms, you have a whole bunch of them and everywhere where this magnetic field touches it through plasma it becomes a source giving the appearance that it moves but in reality is a series of atoms triggered in charge just like a running light.

    Cool!

  32. Lawrence B. Crowell says:

    That is basically it. Again I am not a plasma maven, so there are details missing. It is some form of charge separation wave with a group velocity.

    LC

  33. Olaf says:

    I am not an abstract formula guy, I need some visual to understand it.

    I was thinking a bit further when I was driving to get my GF.

    It could be even simpler visualized assuming that you have a laser at the centre of the pulsar. Probably a laser at the 2 endpoints. Now spin it very fast, everywhere the laser gets to the surface it activates the atoms and that point become a source. Interesting the laserlight (plasma/magnetic field) does not violate the speed of light since the light from the lase still flies at near speed of light depending on the material of the star.
    Now spin the laser realy realy fast and the light even travels like a spiral upwards because of the distance towards the surface.

  34. Lawrence B. Crowell says:

    Think of the laser light as like a machine gun in one of those old video games where the pixel lights would fly around. If you rotate that gun around the screen that is not to different from what happens to a laser pointer when it angle of aim changes.

    LC

  35. Vanamonde says:

    Lawrence B. Crowell, even if I fail to understand all you post, your posts have Great Value and it is my own lack of background that is the fault, a situation I own myself.

    Let no one who narrow mind is smaller than their wide mouth (or trollish fingers in the case) trouble you.

  36. Torbjorn Larsson OM says:

    Ah, thanks Olaf and LBC! Now I can visualize some models of geometry that can fit the process. At times you need to “shoot the crap” with others to get what’s going on.

  37. RUF says:

    “It’s just a model…” –Patsy, Monty Python & the Holy Grail.

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