question is: are we sticking with Einstein?

Discussion in 'All Things Boats & Boating' started by yipster, Sep 24, 2011.

  1. erik818
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    erik818 Senior Member

  2. erik818
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    erik818 Senior Member

    My calculations based on speeding neutrinos put the supernova 1987A at a distance of 14,000 lightyears.

    The time difference between neutrino and light over 730 km was 60 ns in the experiment. 3 hours delay then corresponds to 730km*3*60*60/60^-12 = 1.314 * 10^17 km.
    One lightyear is 365.25*24*60*60 s * 300,000 km/s = 9.47*10^12 km.
    1.314* 10^17 km / 9.47*10^12 km/lightyear = 14,000 lightyears. The article in the link in my previous post puts the supernova at 150,000 lightyears.

    Erik
     
  3. viking north
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    viking north VINLAND

    I wish i had known that six months ago as it relates to my boat build, I would have waited 6 months before making those keel measurement mistakes--Now with time going backwards I've got to face and correct those mistakes again. Like pointing a camera at a camera and observing the video on a monitor just nothing but visual feedback. Good news for wooden boat owners though--Rot will become sound wood again :p
     
  4. ancient kayaker
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    ancient kayaker aka Terry Haines

    Erik: not sure where I made a mistake but you are closer.

    However 1 nS = 10^-9 not 10^-12 (= 1 picosec) so between us we get 14 LY. With a true distance to the supernova of 150,000, if the Cern results are correct, the neutrinos would have arrived 3 * 150,000/14 =32,142 hours before the light or 3.7 years and might not have been noticed.
     
  5. erik818
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    erik818 Senior Member

    Terry: When I doublechecked my calculations I didn't see the now obvious error with the nanosecond. Thank you for the correction.

    Erik
     
  6. ancient kayaker
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    ancient kayaker aka Terry Haines

    I have to admit the answer you got first time is of the order of what I expected to get initially, so I really should have checlked my own calculations more closely. I assume I had a number on the wrong wide of the division sign . . .
     
  7. rwatson
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    rwatson Senior Member

    Thanks for that link.

    I wondered why the 'neutrinos fast than light' discovery wasnt announced then, but further in the article it says

    "These neutrinos interact with atomic nuclei in the water to produce electrons, muons or tau leptons that travel faster than the speed of light in water to produce a shock wave
    of light called Cerenkov radiation"

    The light from the supernovae, would get refracted, distorted, bent by gravity on its travel, hence the relatively miniscule time difference with neutrons etc which are largely unaffected by mass.

    Also, Ancient Kayakers calcs showing the ~3 years difference ties in with the quote from my original post, which estimated about 3 years lead time if neutrinos were faster than light.

    So the Physics article didn't conclude that neutrinos were faster than light - it says

    " ... detected neutrinos from supernova 1987A a full three hours before light
    from the explosion reached Earth"

    they were *detected* earlier - and only by three hours.

    .... does that make sense ?
     
  8. RayThackeray
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    RayThackeray Senior Member

    Yes it does. The supernova observations were categorically clear in validating Einsteinian velocity limit as c. These OPERA results are a new departure.
     
  9. daiquiri
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    daiquiri Engineering and Design

    According to Wikipedia (http://en.wikipedia.org/wiki/SN_1987A) the SN1987A was distant 168000 light years from Earth. In other words, it took 168000 years for the light from the explosion to reach our planet, or 1.47e9 hours. An advantage of 3 hours over 1.47e9 translates into 2.04e-7 % difference.

    On the other hand, the OPERA experiment was performed between sensors placed at 730 km distance. Considering that the speed of light in vacuum is 299792458 m/s, it means that the light would take 2.435e-3 seconds to cover that distance in vacuum. Neutrinos were detected to arrive 60E-9 seconds earlier, yielding a 2.46e-3 % difference.

    The difference between these two numbers is so huge that the two measurements imho cannot be correlated or compared in any way.

    This guy is pointing out to another possible explanation of the OPERA experiment, in line with the current theories: http://www.sciforums.com/showthread.php?p=2862387
    The difference is explained by the fact that neutrinos didn't travel through the vacuum during the experiment.
     
  10. rwatson
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    rwatson Senior Member

    Re-assuring

    that article says

    " In vacuum, instead, neutrinos are expected to propagate at speed less or equal than the speed of light, otherwise the anticipation observed in the SN1987a would have been of years. This superluminal effect in astrophysical
    scenarios of high energy neutrinos is expected to occur only in the inner core of the star when the supernova is starting its catastrophic state and matter is dense and widely structure"

    The point being that the Neutrinos were probably part of the explosion (prior to the body reaching critical mass), therefore created independent of photon production
     
  11. Dave Gudeman
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    Dave Gudeman Senior Member

    Can someone explain why all of these calculations are assuming that the faster-than-light neutrinos in the experiment and the faster-than-light in the supernova would be going at the same speed? Is there some reason to assume that neutrinos have a constant speed?
     
  12. rwatson
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    rwatson Senior Member

    Yes. By their composition, ( as per Photons, which are light ) - their speed is consistent.

    But - their are different types of neutrinoes.
     
  13. erik818
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    erik818 Senior Member

    As I understand it, NO. Neutrinos are poorly understood, partly because they interract so weakly with matter and therefore are very difficult to observe. The neutrino burst 3 hours before the supernova consisted of 24 neutrino interractions (I've also seen the figure 25) in three neutrino detectors in different locations within a few seconds out of an estimated total of somthing like 10^19 neutrinos passing through earth. Anyway, some observed neutrino characteristics can only explained if the neutrino has a very small but non-zero mass. If the neutrino has a mass, it should be able to travel at any speed less than c (according to relativity). The estimated mass is in the order of 500,000 times less than the electron, so if the speed is considerably slower than c I believe that it would have too little energy to be detected. If for some other reason the neutrino energy must be constant, the speed must also be constant.

    I'm not comfortable with the explanations for the early arrival of the neutrinos. Basically the argument is that because the neutrinos cannot have travelled faster than light, there must be another explanation. One such explanation is that they were emitted before the light. I dont' believe that it is possible that the mass between earth and the supernova could slow the light down 3 hours without obscuring the subernova from sight, but maybe someone can provide an argument to the contrary.

    If there was a neutrino burst from the supernova, that was dispersed in time by the time the burst reached earth, the neutrinos wouldn't have been possible to detect above the background neutrino noise. An argument that all emitted neutrinos were arriving in that -3h neutrino burst is that the number of interractions agree reasonably well with the expected number of interractions that would occur from the expected total number of emitted neutrinos from teh supernova. I don't know the error margin in the estimates, but based on our limited knowledge about neutrinos and supernovas it has to be large.

    Erik
     
  14. Boston

    Boston Previous Member

    I think this can all be figured out mathematically and then checked with the observed data. Long time ago I dreamed up, or thought I did, I later found some folks discussing it on a physics forum, a formula that seems to isolate mass on one side and frequency on the other.

    HV/C=M

    planks constant times the velocity of the particle ( which is the interesting element here cause isn't the spin component of the quantum number, motion, IE velocity ? I'd say it is and if so if that spin was of sufficient speed it can be shown to effect mass. If mass is reduced to zero or a negative then its perfectly possible for an object of mass in one velocity condition to have less mass in another.

    Means light speed should be attainable for objects that can sustain velocities other than there typical quantum spin number. Assuming you consider that spin a velocity.

    if that makes any sense,. I know some of the common denominators are difficult to justify in that formula but once enough twisting and tweaking is done it should work.

    I think?

    maybe?

    My math skills are way rusty but it seems reasonable
     

  15. ancient kayaker
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    ancient kayaker aka Terry Haines

    The following explanation is the simplest that will work; it relies on these assumptions:

    1. The progenitor of the supernova was the largest of its type (Blue Giant)
    2. The neutrinos and light were generated at the same time at the center of the star
    3. The light traveled slower within the star due to its dielectric constant
    4. The neutrinos traveled at the speed of light all the way, no faster, no slower

    If these assumptions are valid then the light could have been delayed within the star by 3 hours, lagging behind the neutrinos for the rest of the trip. This explanation calls for an average dielectric constant of around 200. Substances with higher DCs are routinely made on earth, and given the extreme density of a large star this is believable.

    Here’s the math such as it is:

    Blue Giant radius max. 25x Sun’s radius
    Sun’s radius 695500 kilometers or 2.3 light-seconds
    Mean dielectric constant of star 200
    Time for light to travel from center to surface of star 25 x 2.3 x 200 / 3600 = 3.2 hours
     
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