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Thread: Neutrinos faster than the speed of light????!!!!

  1. #136
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    Quote Originally Posted by Chogy View Post
    It takes a very special person to understand cosmology. I was thinking on this thread earlier while reading a science article about black holes. If the gravity of a black hole is strong enough to absorb light, wouldn't that by definition also slow light down so long as the light is outside the event horizon?

    Consider this thought experiment. You've got a black hole with a 10km event horizon. Place an LED light 1mm outside the event horizon, in line with the center of the BH and an outside observer. Turn on the light. The light exiting the LED can escape the BH and travel to the observer, but will it be measured at C? If not, is this purely due to time dilation? Velocity is distance over time, V=d/t. In our thought experiment, the distance is known, and fixed. The only variable is the presence of the black hole. Take the black hole away, and repeat the experiment.

    If we measure C identically both times, the obvious answer is that the black hole is warping time. Makes my head hurt.
    Light interacts with most 'stuff' (all the stuff we see; that's why we see it). It is slowed down by most matter. Neutrinos interact with very few things (rock included). For light a human body, for example, is quite a dense mass of material (thus we cast shadows) but for neutrinos a human body is as good as a vacuum.

    It's easier if you think of it in terms of invisibility: We normaly see in light terms; if it's 'invisible' light is passing around or through it. We also use devices that look in infrared, radio waves etc etc which show up heat and various other properties. Say we had a pair of spectacles for each; each pair of spectacles would show us that some material/heat source etc is there. If I had a pair of 'neutrino spectacles' more than 99.9% of the universe would be invisible; I'd have lots of 'dark matter'!

  2. #137
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    Doubts cast on faster-than-light neutrinos experiment

    Measurements by Gran Sasso physicists suggest neutrinos cannot have travelled faster than the speed of light

    Ian Sample, science correspondent
    guardian.co.uk, Monday 21 November 2011 14.44 EST

    The idea that subatomic particles can travel faster than the speed of light in contravention of the currently accepted laws of physics has been dealt a serious blow by researchers who share the lab of the team that made the original finding.

    In September, physicists working on an experiment called Opera at the Gran Sasso laboratory in Italy announced that neutrinos sent there from Cern near Geneva seemed to complete the 450 mile (720km) journey faster than a beam of light.

    The group went on to refine their experiment and reported on Friday that the ghostly particles still appeared to be breaking nature's speed limit in a troubling violation of Einstein's theory of special relativity that would allow information to be sent back in time and so play havoc with the principle of cause and effect.

    But measurements by a competing team of physicists at the Gran Sasso laboratory now suggest the neutrinos cannot have travelled faster than the speed of light as they hurtled through the Earth from Switzerland to the Gran Sasso lab near Rome in central Italy.

    The team, who work on an experiment called Icarus, tested an argument described in a recent paper by Andrew Cohen and Sheldon Glashow at Boston University, who argued that faster-than-light or "superluminal" neutrinos would lose energy by spewing out electrons and their antimatter partners called positrons. Professor Glashow shared the Nobel prize for physics in 1979.

    When Maddalena Antonello and others on the Icarus team analysed the energy of the neutrinos arriving at Gran Sasso, they found no evidence that they had lost energy the way Cohen and Glashow predicted. The finding has bolstered the view of many physicists who believe the Opera result is an error of measurement.

    "Cohen and I argue that superluminal neutrinos ... must produce electron - positron pairs. They do not ...Thus, we conclude that the neutrinos are NOT superluminal" Prof Glashow told the Guardian. He went on to add that if neutrinos did travel faster than light "we would have to abandon much of what we think we know, much more than 'just' special relativity."

    Jim Al-Khalili, a professor of physics at the University of Surrey who pledged to eat his boxer shorts live on television if the Opera result was proved true, was similarly sceptical that neutrinos can move faster than light.

    "Opera measures the time of neutrino travel and hence their speed, whereas Icarus - who also detect the same neutrino beam - measure the spread in energy of the arriving neutrinos. They found that the neutrinos don't lose energy on their route. The problem of course is that they should do, if they were travelling faster than light. This is the equivalent of the sonic boom when something goes faster than sound."

    "Usually we see this effect when particles go faster than light through transparent media like water, when light is considerably slowed down. It's called Cerenkov radiation. So these neutrinos should have been spraying out particles like electrons and photons in a similar way if they were going superluminal - and in the process would be losing energy. But they seemed to have kept the energy they started from, which rules out faster-than-light travel."

    Matt Strassler, professor of theoretical physics at Rutgers University in New Jersey, said the Icarus results did not completely rule out faster-than-light neutrinos. "Cohen-Glashow and Icarus have shown that if Opera is correct, and Einstein's relativity must be modified, then that modification must also cleverly eliminate the Cerenkov-like radiation that would have affected both Opera and Icarus. That's a very tall order, to be sure; but until someone proves that no such modification is possible, we can't firmly conclude Opera is wrong," he said.

    Doubts cast on faster-than-light neutrinos experiment | Science | The Guardian
    To be Truly ignorant, Man requires an Education - Plato

  3. #138
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    I am actually surprised by all of this. We can never test these theories. Our spieces will die before we can exploit them. At best, we can send our message further into the stars before we die. So, we send our message by neutrinos instead of radio. We will still die before we leave the galaxy ... if we can leave our solar system before we die.

    I am surprised that none of you got Choggy and my reference. Our future are our machines. That is our only legacy. Machines will survive where we will not.

    But then, even our machines will have their limits. No machine of our current built will ever approach our galactic black hole.

    In short, you want a legacy? The old military motto stands. Live Fast! Die Young! And leave a good looking corpse. That stands to civilizations as well as men.
    Chimo

  4. #139
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    Quote Originally Posted by Officer of Engineers View Post
    Our future are our machines. That is our only legacy. Machines will survive where we will not.

    But then, even our machines will have their limits. No machine of our current built will ever approach our galactic black hole.

    In short, you want a legacy? The old military motto stands. Live Fast! Die Young! And leave a good looking corpse. That stands to civilizations as well as men.
    If I may say O of E, never say never. Modern futurologists have a great deal of difficulty accurately "foreseeing" advances in science and technology - to the extent that predictions about trends 10 to 20 years in the future have a habit of coming very wide of the mark - such is the rate of change and spread of developments. So while for instance I see no chance of humans reaching even the closest star in next couple of centuries we have (providing we don't destroy ourselves of course) thousands of years to consider options for doing this if we wish.

    And while out machines might well be left behind if the human race suddenly became extinct given recent trends in electronics/biochemistry and neuroscience I’m not sure necessarily sure that the distinction between man and machine will be so clear cut say 200 years from now. As for "reaching" the stars there is no rush. Even using something similar to an Orion Drive it would be theoretically possible to send a payload to another local star system in a relativly short time. (And we will certainly know which ones are worth visiting long before we have even the slightest chance of getting there!) Meanwhile we have Mars and Venus to "practice" on in our backyards and there is at this stageat least no need for us to to rush. Several missions over a number of decades to one or two systems would suffice, after that the process becomes self sustaining - to the extent that these one or two colonies can eventually repeat the process themselves if they consider it worthwhile.

    Also we live in interesting times what with Relativity and the Standard Model comming in for (potential) review of late - we might not know ift all when it comes to theoretical physics just yet. I intend to try and stick around for the next few centuries to see what happens .

    Cheers
    Last edited by Monash; 23 Nov 11, at 12:05.

  5. #140
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    Quote Originally Posted by Officer of Engineers View Post
    I am actually surprised by all of this. We can never test these theories. Our spieces will die before we can exploit them. At best, we can send our message further into the stars before we die. So, we send our message by neutrinos instead of radio. We will still die before we leave the galaxy ... if we can leave our solar system before we die.

    I am surprised that none of you got Choggy and my reference. Our future are our machines. That is our only legacy. Machines will survive where we will not.

    But then, even our machines will have their limits. No machine of our current built will ever approach our galactic black hole.

    In short, you want a legacy? The old military motto stands. Live Fast! Die Young! And leave a good looking corpse. That stands to civilizations as well as men.
    Considering that steam power is about 300yrs old, modern physics about 100yrs old, computers 50-60yrs old and the genome mere decades; that in theory we can produce limitless clean energy by fission (though the mechanics are currently lacking) and many other as yet mechanicaly 'undoables' are theoreticaly possible I personaly regard this view as somewhat shortsighted. Imagine fighting at the Battle of Bosworth in 1485 and someone tells you that within 500yrs men will walk on the moon! He'd probably be burned for heresy or something but you certainly would not believe it. Modern science in terms of human existence has only just started. We have far to go yet. It may well be that future space explorers are geneticaly manufactured 'cyborgs' with a virtualy limitless life span. The fact is that in theory we can just about create such 'beings' - and we have barely scratched the surface.

    Also the whole point of traveling faster than light means (if proved possible) that the 'space/time continuum' can be broken: You can arrive somewhere before you left! Distance therefore would become meaningless.

  6. #141
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    Everything a man--not mankind--needs can be found right here on earth and within himself.

    The drive to perform amazing feats through science is a reflection of man's innate (nature given) drive to find the truth he needs to fulfill the purpose of his existence. Unaware of this, many of the feats man performs miss the mark, but not all.

    Nature is an intelligence above us and we dance to her fiddle. Look inward and you will find her plan for you. Look outward and you will be forever be in a muddle.

    Science is a useful tool often misused to satisfy athletic minds. It at least shows that man has the intelligence to discover pertinent truths, but its performance shows it lacks the focus to get on with it.
    snapper likes this.
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  7. #142
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    Profound! Suppose Tankies little green men are out there though? Shouldn't we eat them/ask them what they think?

  8. #143
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    Ohh,I'm sure will eat them.It's our nature.That's if they're comestible and they don't eat us first.
    If they make the mistake of not eating us,they're finished.We'll smile nicely until we learn their technology.We'll leave enough survivors to populate the zoo's
    Those who know don't speak

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