May 14, 2012

Consideration for Sub-Millisecond Pulsars (or the Lack Thereof)

Posted by in categories: existential risks, particle physics, physics, space

On a casual read of the appraised work of Duncan R. Lorimer on Binary and Millisecond Pulsars (2005) last week, I noted the reference to the lack of pulsars with P < 1.5 ms. It cites a mere suggestion that this is due to gravitational wave emission from R-mode instabilities, but one has not offered a solid reason for such absence from our Universe. As the surface magnetic field strength of such would be lower (B ∝ (P ˙P )^(1÷2)) than other pulsars, one could equally suggest that the lack of sub millisecond pulsars is due to their weaker magnetic fields allowing CR impacts resulting in stable MBH capture… Therefore if one could interpret that the 108 G field strength adopted by G&M is an approximate cut-off point where MBH are likely to be captured by neutron stars, then one would perhaps have some phenomenological evidence that MBH capture results in the destruction of neutron stars into black holes. One should note that more typical values of observed neutron stars calculate a 1012 G field, so that is a 104 difference from the borderline-existence cases used in the G&M analysis (and so much less likely to capture). That is not to say that MBH would equate to a certain danger for capture in a planet such as Earth where the density of matter is much lower — and accretion rates much more likely to be lower than radiation rates — an understanding that is backed up by the ‘safety assurance’ in observational evidence of white dwarf longevity. However, it does take us back to question — regardless of the frequently mentioned theorem here on Lifeboat that states Hawking Radiation should be impossible — Hawking Radiation as an unobserved theoretical phenomenon may not be anywhere near as effective as derived in theoretical analysis regardless of this. This oft mentioned concern of ‘what if Hawking is wrong’ of course is endorsed by a detailed G&M analysis which set about proving safety in the scenario that Hawking Radiation was ineffective at evaporating such phenomenon. Though doubts about the neutron star safety assurance immediately makes one question how reliable are the safety assurances of white dwarf longevity – and my belief has been that the white dwarf safety assurance seems highly rational (as derived in a few short pages in the G&M paper and not particularly challenged except for the hypothesis that they may have over-estimated TeV-scale MBH size which could reduce their likelihood of capture). It is quite difficult to imagine a body as dense as a white dwarf not capturing any such hypothetical stable MBH over their lifetime from CR exposure – which validates the G&M position that accretion rates therein must be vastly outweighed by radiation rates, so the even lower accretion rates on a planet such as Earth would be even less of a concern. However, given the gravity of the analysis, those various assumptions on which it is based perhaps deserves greater scrutiny, underscored by a concern made recently that 20% of the mass/energy in current LHC collisions are unaccounted for. Pulsars are often considered one of the most accurate references in the Universe due to their regularity and predictability. How ironic if those pulsars which are absent from the Universe also provided a significant measurement. Binary and Millisecond Pulsars, D.R. Lorimer:


Comments — comments are now closed.

  1. PassingByAgain says:

    20% percent of the energy of LHC collisions unaccounted for? Where have you found this nonsense???

  2. Tom Kerwick says:

    That 20% figure of unaccounted for mass/energy was a concern raised to me as fact by your friend Prof Otto Rossler last week. Perhaps Otto can elaborate for you…

  3. PassingByAgain says:

    Do you still take Rossler’s “facts” at face value? How old are you?

  4. Tom Kerwick says:

    Didn’t take it as a fact — took it as a concern. It would be naive to think all energy could be accounted for, though admittedly 20% seems quite high. Perhaps Otto can elaborate…

  5. PassingByAgain says:

    Missing energy is the main search channel for new physics at the LHC, and it is eagerly looked for. In fact, it has been a source of some frustration in the physics community that all searches for missing energy in the 2011 data yielded NULL results. And now you can write with a straight face that 20% of the energy is “unaccounted for”, and that this creates “concerns”? What the hell are you talking about?

  6. Tom Kerwick says:

    You may be misinterpreting unaccounted loss of energy with getting results of statistical significance — which is quite different. Again I just mentioned in passing that there is such concern/allegation. I await on Otto to elaborate on where he heard such a figure…

  7. Tom Kerwick says:

    I trust Otto will be comfortable with me quoting the relevant piece of correspondence:

    Tom — “In the event that MBH cannot be detected by their theorized radiation, then the only way to guarantee that such are not being created is to ensure there is no unaccounted loss of (TeV-scale) energy from collision experiments, i.e. the collisions must be accountable to their products.” Otto — “Yes, but they are not. CERN says at different places that they cannot account for 100 of the energy in the collisions — I believe it is about 20 percent that unavoidably remain unaccounted for.”

    Therefore I should clarify — this was expressed just as a concern/belief and not as a fact. I would be interested in seeing what the real percentages are. I would have expected the figures to be quite small but not NULL as you state. How old are you?

  8. PassingByAgain says:

    Well then, it all depends on what you mean by “unaccounted for”. For example, the ATLAS and CMS detectors cannot catch particles that fly too close to the direction of the beam (indeed, in searches for new physics they look for missing “transverse” energy). But this does not mean that one doesn’t know what happened to those particles. Indeed, the average fraction of particles (and of energy) that escapes along the beam can be calculated, and if the observed values had turned out different from the theory prediction believe me, you would have heard about it. Why this should be cause of any “concern” is beyond me. I think that YOUR friend Otto just repeated some random number that he had read somewhere without understanding what it meant.

  9. Niccolò Tottoli says:

    BTW.: The energy loss because of the creation of micro black holes (MBH) could be much less in the case that only the remnants of MBH are stable.