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.
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