p.s. Years ago, I had undertaken a similar thought experiment on a train that the author, R. Prasannan,below shares. i came up with the same results. This is why I raise the question of why Einstein stood so firm on this believe that nothing goes faster than light. Even with the concept of the elasticity of time, the fundamental math calls for there to be a curved universe and actual speeds faster than light in the universe--or at least in a vacuum in the universe.
Fast train to the past? Holy Ghost!
By R. Prasannan, THE WEEK (India)
Imagine a train, travelling at 100km per hour. If one of the
passengers walks at a speed of 5kmph from the rear end of his coach
towards the front, his travelling speed should be 105kmph. That is what
mathematics and common sense tell us.
What if it were a "superfaaast' express travelling at 2,40,000 kilometres per second, and the scientist were "waaaalking' at 1,00,000kmps? Shouldn't his travelling speed be 3,40,000kmps? That is what mathematics and common sense tell us.
No way, say physics and Albert Einstein. His speed cannot be more than 3,00,000kmps, which is the speed of light. Nothing can travel faster than light, Einstein said more than a hundred years ago in his Special Theory of Relativity.
Einstein can't be wrong. If Isaac Newton's Laws of Motion are the Old Testament of science, Einstein's General and Special Theories of Relativity are the New Testament. Together with Light, they make the Holy Trinity of physics--Newton the Father, Einstein the Son, and Light the Holy Ghost. No blasphemy in the statement. J.B.S. Haldane called Einstein the greatest Jew after Jesus.
But now a bunch of scientists, sitting a few kilometres under the Alps, are committing blasphemy. They fired a few particles called neutrinos over 730km from CERN, Europe's particle physics lab near Geneva in Switzerland, to Gran Sasso National Laboratory near L'Aquila in Italy. If they had switched on a powerful torch, the beam should have travelled this distance in 2.4 milliseconds. But the neutrinos reached 60 nanoseconds (or 60 billionths of a second) faster. The experiment was replicated in November, and they found that neutrinos continued to arrive 60 nanoseconds earlier than light. Photo-finish, literally! This means, neutrinos can travel six kilometres more than light can in a second.
The blasphemy is not in conducting such an experiment in such an ungodly place. (They are also trying to find the God particle, but that is another story.) Nor is there blasphemy in saying that Einstein, like the pope, is not infallible. The blasphemy is in the implication of their claim--that a time machine, as imagined by H.G. Wells, is possible, at least mathematically, if not physically. That one can travel back in time, again mathematically, and watch Gandhi making salt at Dandi or Shah Jehan building the Taj Mahal.
How? Imagine taking a spaceship powered by neutrinos and flying out. At some stage, the ship should overtake the light particles that emanated from Shah Jehan's construction site in 1631. When those beams fall in your eyes, you see Shah Jehan inspecting the walls and shouting orders, which you won't hear, since sound travels much slower. (It is better that way; he had a foul mouth.)
The picture gets more maddening, if one could get into the past and alter it, as it almost happened in Wells' still-cherished classic Time Machine and the long-forgotten (pity!) film The Final Countdown. In the movie, the modern nuclear-powered warship USS Nimitz is taken by a magnetic storm into the past, to the point of time when the Japanese kamikaze pilots were about to attack Pearl Harbor. Now, what if Nimitz, which possessed enough firepower to blow up into the blue the entire air force of Japan, had intervened in the action? World War II would have ended before Pearl Harbor was attacked.
Think of the neutrino as a "suuuuuuuuuuperfast' P.T. Usha in a race. On reaching the finishing line, she turns around and looks towards the track. What does she see? Herself racing towards her. Differently put, she sees herself, as she existed just before reaching the finishing line.
How? We see an object before us when the light from the object reaches our eyes. (You are reading this article because light from the page is reaching your eyes.) Neutrino Usha (the name means the light of dawn!) has reached the finishing line, but the light from her body, being slower than she, is yet to reach the finishing line. When it finally reaches, she is already there to receive it in her eyes. She sees herself as she existed a while ago. She sees her own past. "Like sending a telegram to the past," as a CERN scientist described the neutrino phenomenon.
Astrophysicists would say one always sees only the past. Since light has a finite speed, we, or our astronomers, are always seeing celestial phenomena that happened several thousand light-years away and ago. Since light takes eight minutes to reach us from the sun, we are seeing the sun of eight minutes ago. To put it differently: suppose the sun were to "switch off' right now; the earth will get dark only eight minutes later. Or as Fritjof Capra put it in The Tao of Physics, the book that popularised New Physics post-Einstein, "We see the nearest star as it existed four years ago, and with our powerful telescopes we can see galaxies as they existed millions of years ago."
Now, what the neutrino under the Alps, if it had turned around to watch the track it had traversed, would have seen is itself as it existed a while ago. Somewhat like looking into a mirror and seeing yourself. We know the image in the mirror is not real. But what if it were real? It would be as weird as Lewis Carroll's Through the Looking-Glass in which Alice is sucked into the mirror-world. By the way, Lewis Carroll taught mathematics in Oxford.
The CERN claim must have already set dozens of H.G. Wellses, Lewis Carrolls and Carl Sagans pounding at their keyboards, but the world's physicists and mathematicians, still grappling with the claim, are setting the cyber world afire with theories, exclamations and explanations. "It's not very easy to overrule Einstein's theory," said Prof. Victor Flambaum of the University of New South Wales. "There have been thousands of tests of special relativity, people have confirmed it, there's never been a confirmed deviation." Added M.V.N. Murthy, professor of physics at Chennai's Institute of Mathematical Sciences, one of the few places where Newton and Einstein would have worked, had they been Indians living in the 21st century: "This has to be taken seriously. This has also to be verified again within the framework of quantum mechanics and relativity." Incidentally, India's physicists, including Murthy, are working to set up a CERN-like laboratory under the Nilgiri mountains in Theni (see box).
The first question that scientists asked on learning of the CERN experiment was: could the lab have erred? Error in light velocity experiments so far conducted has been by 10 nanoseconds. But here, neutrinos beat light by 60 nanoseconds, which means the neutrinos didn't cheat.
One reason to say so is that neutrinos can't cheat. They are weakly interacting subatomic particles which have no electric charge, and they pass through ordinary matter almost unaffected. About 65 billion neutrinos coming from the sun are passing through every square centimetre of the earth facing the sun straight. "Billions of neutrinos stream through our body every second," says Prof. N. K. Mondal, spokesperson for Tata Institute of Fundamental Research (another place the great two could have chosen) which is planning to build the Nilgiri lab, "yet only one or two of the higher energy neutrinos will interact with you in your lifetime".
Secondly, neutrinos beating light, or breasting the tape with light, has been suspected even earlier. In 1987, scientists observed that neutrinos from a supernova (star explosions which had been noted since the time of Kepler) which had exploded in a galaxy had reached along with light, after travelling 1,55,000 light-years. "If neutrinos are 60 nanoseconds faster in 730km, the neutrinos from the supernova which is 1,55,000 light-years away, should have arrived four years earlier. But we observed them simultaneously," said Murthy. In 2007, the MINOS experiment by Fermilab in the US had reported similar result, but, as Prof. Craig Savage of Australian National University put it, "that wasn't statistically significant. There was some reasonable probability that what they were seeing was just a statistical fluctuation."
Murthy also points to the fact that the speed of light one is talking about is when it is travelling through vacuum. The neutrinos in the experiment are travelling through earth's mantle. Even light is known to be affected by the medium, causing it to be superluminal. "Neutrinos may be experiencing the effect of the medium just as in the case of superluminous light." All the same, "we are not foreclosing anything," said Prof. G. Rajasekaran of the Institute of Mathematical Sciences. "In science we cannot jump to conclusions, and say Einstein was wrong. Nor can we close our minds to anything, to say Einstein could never be wrong. I would only say I won't give up Einstein that easily."
Interestingly, Indian scientists had talked of a particle which moves faster than light. E.C.G Sudarshan, who worked at the Chennai institute (Indian scientists like Prof. Ranjit Nair of the Centre for Philosophy and Foundations of Science believe he was unjustly overlooked for the Nobel Physics Prize) had talked of hypothetical particles called tachyons which move faster than light, and which cannot slow down to less than the speed of light. But as Rajasekaran put it, "tachyons concept has innumerable problems; it is not clear if we can build a physics out of it. As a physical entity it does not exist."
In 1962, Jayant Narlikar, along with Fred Hoyle, Thomas Gold and Hermann Bondi, found that in a universe that is expanding after a big bang event, neutrinos would turn up at a detector before they were emitted. "Only future-going neutrinos were possible in the steady state cosmology while the ever-expanding big bang models gave neutrinos travelling into the past," Narlikar supposedly told Michael Brooks of New Scientist, and author of Free Radicals: The Secret Anarchy of Science. "If you see firm evidence of neutrinos arriving at the detector before they are sent, that can't happen in a steady state cosmology, so the big bang has to be right. Or equivalently, no faster-than-light neutrinos, no big bang." Now, the faster-than-light neutrinos can be interpreted as travelling into the past, says Brooks.
But as Brooks puts it, "Apart from a few die-hards, no one now doubts the big bang theory is correct anyway. Almost everyone doubts the Gran Sasso results." As Nigel Calder wrote in Einstein's Universe: The Layman's Guide, "If objects could go faster than light they would evidently be going "backwards in time'. "Imagine watching an object coming towards you faster than light. You would see it apparently going away from you, back on its tracks. It would appear near --to you, at the end of its journey, --before the light from farther off telling of its coming."
Something similar is known in the world of supersonics, where things travel faster than sound. The bullet from a hunter's rifle, which flies faster than sound, hits a bird before it hears (if it is still alive) the report of the gun. "But in the case of light," says Calder, "the motion of which is closely coupled with the fundamental workings of time in the universe, the consequences are serious. For example, if you are shot, you could in theory send a signal faster than light and backwards in time, which would stop the person pulling the trigger that fired the shot which had already hit you."
To make it "light'er, in the world where something can travel faster than light, cause-and-effect ceases to exist. Not only physics, but the world we know from Newton, Einstein and Light works on cause-and-effect principle.