Posted at 09:42 AM ET, 02/23/2012 TheWashingtonPost
Neutrinos are not faster than light — why you should never doubt Einstein
Five months ago today, the scientific community was sent into a tailspin.
(AP) Scientists at CERN, the world’s largest physics lab, announced a startling finding: Subatomic particles, called neutrinos, were found traveling faster than the speed of light. Albert Einstein, it seemed, should be rolling over in his grave. His theory of relativity could be dead. Not so fast. On Wednesday the CERN team said they had made a mistake, Science Magazine reported. Something had gone wrong with the timing gear, and with the optical fiber connection. Neutrinos, they said, probably don’t travel faster than light, at 186,000-miles-per-second. Or at least they haven’t been able to prove it yet. “Always check the cable before doubting Einstein,” Forbes wrote with glee Wednesday. Five other reasons you should never doubt the father of modern physics after the jump.
His brain may have been better than ours.
Einstein’s brain had a greater number of glial cells per neuron, according to a study in the Lancet medical journal in 1999. The authors of the study said that more neurons indicated the brain had an increased “metabolic need,” meaning it needed and used more energy. “In this way, perhaps Einstein had better thinking abilities and conceptual skills,” University of Washington researchers wrote recently.
Einstein made highly complex subjects simple.
Capillary attraction. Brownian motion. Photons and energy quanta. Wave-particle duality. Einstein studied all of these phenomena and sought to break them down and articulate them simply. “Any intelligent fool can make things bigger, more complex, and more violent,” he once said. “ It takes a touch of genius — and a lot of courage — to move in the opposite direction.” During his free time, Einstein said he refused to play Scrabble or other games that required mental energy, to save that energy for his work .
So far, there has been no one like him.
Einstein, contrary to popular belief, did not win the 1921 Nobel Prize in Physics for his work on relativity. Back in 1905, Einstein wrote five ground-breaking essays that Encyclopedia Britannica says “forever changed man's view of the universe.” The Nobel Prize committee awarded Einstein for these papers, and for his overall “services to theoretical physics.” Since that award, generations of physicists and students have come to see Einstein’s word as law. Scientists have been hard-pressed to find another genius to replace him.
If Einstein was wrong, it probably would already have been proven.
Drexel University astrophysicist Dave Goldberg told National Geographic (NG) in August that if faster-than-light neutrinos did exist, it’s likely they would have been observed in nature before now.
In 1987, he said, detectors on Earth identified neutrinos and light particles (photons) from an exploding star. Both types of particles got to our planet at almost exactly the same time.
Even if Einstein were wrong, scientists wouldn’t stop listening.
Even if the CERN results were right and Einstein was wrong, it wouldn’t invalidate his theories of general and special relativity, Stanford University astrophysicist Louis Strigari told NG. Those theories — right or not — explain a remarkable range of observed phenomena in the universe, Strigari said.
“Even if relativity turned out to be wrong,” Goldberg said, “it's clearly very, very close to being right.”
Neutrinos not faster than light;
ICARUS experiment contradicts controversial claim.
16 March 2012
The ICARUS detector in Gran Sasso, Italy, has confirmed that neutrinos travel no faster than the speed of light.INFN Gran Sasso National LaboratoryArticle tools
Neutrinos obey nature's speed limit, according to new results from an Italian experiment.
The finding,posted to the preprint server arXiv.org, contradicts a rival claim that neutrinos could travel faster than the speed of light.Neutrinos are tiny, electrically neutral particles produced in nuclear reactions. Last September, an experiment called OPERA turned up evidence that neutrinos travel faster than the speed of light
Located beneath the Gran Sasso mountain in central Italy, OPERA detected neutrinos sent from CERN, Europe's premier particle-physics laboratory near Geneva, Switzerland. According to the group's findings, neutrinos made the 731-kilometre journey 60 nanoseconds faster than predicted if they had travelled at light speed.
The announcement made international headlines, but physicists were deeply sceptical. The axiom that nothing travels faster than light was first formulated by Albert Einstein and is a cornerstone of modern physics. OPERA defended its announcement, saying that it could find no flaw in its measurement.Now another experiment located just a few metres from OPERA has clocked neutrinos travelling at roughly the speed of light, and no faster.
Known as ICARUS, the rival monitored a beam of neutrinos sent from CERN in late October and early November of last year. The neutrinos were packed into pulses just 3 nanoseconds long. That meant that the timing could be measured far more accurately than the original OPERA measurement, which used 10-microsecond pulses.“Our results are in agreement with what Einstein would like to have,” says Carlo Rubbia, the spokesperson for ICARUS and a Nobel prizewinning physicist at CERN. Neutrinos measured by the experiment arrived within just 4 nanoseconds of the time that light travelling through a vacuum would take to cover the distance, well within the experimental margin of error.
Because the pulses from CERN were so short, ICARUS measured only seven neutrinos during the late autumn run, but Rubbia says that the relatively low number does not matter. “How many times do you have to say 'zero' to make sure it's zero?” he asks.The findings are yet another blow to OPERA, which was already under intense scrutiny from the wider experimental community. Almost as soon as the announcement was made, physicists began trying to poke holes in the OPERA analysis, and on 23 February researchers from within the OPERA team announced that they had uncovered possible timing problems with their original measurements.
Those problems could have led to the 60-nanosecond discrepancy.Dario Autiero, a physicist at the Institute of Nuclear Physics in Lyon, France, and physics coordinator for OPERA, welcomes the latest result. He notes that OPERA continued to detect faster-than-light neutrinos in October and November, when the shorter pulses were used. The team continues to search for possible sources of error, he says.For some, the new measurements settle the matter once and for all. “The OPERA case is now conclusively closed,” says Adam Falkowski, a theoretical physicist at the University of Paris-South in Orsay, France. But Rubbia says that he is still awaiting further measurements set to be made later in the spring by OPERA, ICARUS and two other experiments inside Gran Sasso.“Had we found 60 nanoseconds, I would have sent a bottle of champagne to OPERA,” Rubbia says. But as it stands, he suspects he will be toasting Einstein. “It's quite a relief, because I'm a conservative character,” he says.
26 September 2011 9 (Wired Magazine)
Neutrinos and the Speed of Light — A Primer on the CERN Study
Cross section of the CNGS experiment through the Earth. (Image: CERN)
Recently, a group of physicists have been working to measure the neutrinos generated from a particle accelerator at CERN. This group discovered neutrinos arriving faster than would have been expected and they appear to be traveling faster than the speed of light itself, but they draw no definitive conclusions. This has been widely reported as being the end of Relativity, but this is not the case at all.
Let’s take a look at what is going on in the experiment and what was reported in the journal article.
First, it might help the reader to gain an understanding of the neutrino. Neutrinos are interesting little neutral particles that have almost zero mass. Due to their nature, they can pass through matter without being absorbed.
There are three known types of neutrinos: the electron neutrino, the muon neutrino, and the tau neutrino.
The experiment in the journal article is referred to as CERN neutrinos to Gran Sasso, or CNGS. The CNGS team is searching for a phenomenon known as neutrino oscillation where muon neutrinos may change into tau neutrinos. A secondary goal of the experiment is to measure neutrino velocity to a great accuracy. In the experiment, neutrinos are generated at the Super Proton Synchrotron(SPS) particle accelerator at the CERN LHC complex in Geneva and further accelerated down a 1 km beam line toward the Gran Sasso National Laboratory in Italy. At Gran Sasso, a detector instrument called OPERA measures the neutrinos. The distance from CERN to Gran Sasso is 732 km straight through the Earth, traveling up to 11.4 km below the Earth’s surface.
Remember, neutrinos don’t interact with matter so the Earth is invisible to the tiny particles.The distance between the two systems is known to within 20 cm.
Time is also measured with extreme precision utilizing GPS timing signals and a cesium atomic clock. The GPS used in timing also allows the team to track any small movements in the Earth itself. This even allowed consideration of the effect of the L’Aquila Earthquake that moved the OPERA detector 7 cm.
Due to the nature of the experiment, the time is not calculated with a simple, stopwatch style, start to finish measurement. It instead relies on measurements and comparisons of probability distribution functions at the source and the detector. In other words, there is a lot of math involved.
In addition to understanding the timing and position variations in the experiment, the physicists also took into account many other variables, such as day versus night and seasonal changes. The sensitivity of this experiment is roughly an order of magnitude better than previous experiments.
The speed of neutrinos is measured and compared to the speed of light by subtracting the expected time for light to travel the distance from the time for the neutrinos to travel the same distance. One would normally expect this to be zero for neutrinos traveling at the speed of light or negative for any value below the speed of light.
The case presented in the article shows a positive value of 60.7 nanoseconds with statistical and systematic errors providing not nearly enough potential difference to account for the positive value. This value has six-sigma significance. This is, obviously, a stunning finding.
The final paragraph is what appears to be overlooked all too often in the reporting on this finding:
Despite the large significance of the measurement reported here and the stability of the analysis, the potential great impact of the results motivates the continuation of our studies in order to investigate possible still unknown systematic effects that could explain the observed anomaly. We deliberately do not attempt any theoretical or phenomenological interpretation of the results.
This is an important paragraph. This is the group of physicists, together, stating that they don’t know how they came to a result that shows neutrinos apparently exceeding the speed of light.
- They are not drawing any conclusions in this article and are simply providing the finding and the methods used to obtain the finding.
- They are trying to find where there could be errors in their measurements.
- They do not claim that the neutrinos are actually exceeding the speed of light, only that the measurements to date show something unexpected.
- They are reaching out to the high-energy physics community to improve the experiment and data analysis.
- They are not looking to fundamentally change physics but to ensure that they are producing sound data.
We may find that nothing comes of this. We may find that there is an effect known in physics that accounts for the difference. We may find that neutrinos are capable of moving slightly faster than the speed of light. It is simply too early to make definitive, wide-reaching conclusions.
The conclusion that can be drawn from this article is that a group of experimenters found an unexpected result using some of the most amazing and precise instruments and techniques ever created. No matter what is found to be the actual cause of this 60.7 nanosecond variation, the conclusion you can draw is that it is an amazing time in history where such measurements can be made and an exciting time to be a practitioner or admirer of science.
Imagine the findings that will be made by the next couple generations of scientists who are sitting in elementary classrooms right now and just learning that a rainbow is the spectrum of sunlight.
Einstein wouldn’t be disappointed by these findings; he would be intrigued and proud to see the legacy of great science continuing forward.
Brian is a NASA engineer by day and a GeekDad contributor by night. Opinions shared are my own and do not necessarily reflect the opinion of NASA.
23 September 2011 Last updated at 13:03 ET
under scrutiny at Cern
By Jason Palmer Science and technology reporter, BBC News
Enormous underground detectors are needed to catch neutrinos, that are so elusive
as to be dubbed "ghost particles"
A meeting at Cern, the world's largest physics lab, has addressed results that
suggest subatomic particles have gone faster than the speed of light.
contains any mistakes.
If it does not, one of the pillars of modern science will come tumbling down.
Antonio Ereditato added "words of caution" to his Cern presentation because of the
"potentially great impact on physics" of the result. The speed of light is widely held to be the Universe's ultimate speed limit, and much of modern physics - as laid out in part by
Albert Einstein in his theory of special relativity - depends on the idea that nothing can exceed it.
“We want to be helped by the community in understanding our crazy result - because it is crazy”
Thousands of experiments have been undertaken to measure it ever more precisely, and no result has ever spotted a particle breaking the limit.
"We tried to find all possible explanations for this," the report's author Antonio Ereditato of the Opera collaboration
told BBC News on Thursday evening. "We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we
"When you don't find anything, then you say 'well, now I'm forced to go out and ask the community to scrutinise this'."
Friday's meeting was designed to begin this process, with hopes that other scientists
will find inconsistencies in the measurements and, hopefully, repeat the experiment
"Despite the large [statistical] significance of this measurement that you have seen
and the stability of the analysis, since it has a potentially great impact on physics,
this motivates the continuation of our studies in order to find still-unknown systematic
effects," Dr Ereditato told the meeting.
"We look forward to independent measurement from other experiments."
Neutrinos come in a number of types, and have recently been seen to switch
spontaneously from one type to another.
The Cern team prepares a beam of just one type, muon neutrinos, and sends them
through the Earth to an underground laboratory at Gran Sasso in Italy to see how
many show up as a different type, tau neutrinos.
In the course of doing the experiments, the researchers noticed that the particles
showed up 60 billionths of a second earlier than they would have done if they had
travelled at the speed of light.
This is a tiny fractional change - just 20 parts in a million - but one that occurs
The team measured the travel times of neutrino bunches some 16,000 times, and
have reached a level of statistical significance that in scientific circles would count
as a formal discovery.
But the group understands that what are known as "systematic errors" could easily
make an erroneous result look like a breaking of the ultimate speed limit.
That has motivated them to publish their measurements.
"My dream would be that another, independent experiment finds the same thing -
then I would be relieved," Dr Ereditato told BBC News.
But for now, he explained, "we are not claiming things, we want just to be helped
by the community in understanding our crazy result - because it is crazy".
Sep 23, 10:34 AM EDT
Physicists wary of junking light speed limit yet
By FRANK JORDANS
Associated Press GENEVA (AP) --
Physicists on the team that measured particles traveling faster than
light said Friday they were as surprised as their skeptics about the
results, which appear to violate the laws of nature as we know them.
Hundreds of scientists packed an auditorium at one of the world's
foremost laboratories on the Swiss-French border to hear how a
subatomic particle, the neutrino, was found to have outrun light
and confounded the theories of Albert Einstein.
"To our great surprise we found an anomaly," said Antonio Ereditato,
who participated in the experiment and speaks on behalf of the team.
An anomaly is a mild way of putting it.
Going faster than light is something that is just not supposed to
happen, according to Einstein's 1905 special theory of relativity.
The speed of light - 186,282 miles per second
(299,792 kilometers per second) - has long been considered a
cosmic speed limit.
The team - a collaboration between France's National Institute for
Nuclear and Particle Physics Research and Italy's Gran Sasso
National Laboratory - fired a neutrino beam 454 miles (730 kilometers) underground from Geneva to Italy.
They found it traveled 60 nanoseconds faster than light. That's
sixty billionth of a second, a time no human brain could register.
"You could say it's peanuts, but it's not. It's something that we
can measure rather accurately with a small uncertainty,"
Ereditato told The Associated Press.
If the experiment is independently repeated ( my emphasis - K.K. )-
most likely by teams in the United States or Japan - then it would
require a fundamental rethink of modern physics.
"Everybody knows that the speed limit is c, the speed of light. And if
you find some matter particle such as the neutrino going faster than
light, this is something which immediately shocks everybody,
including us," said Ereditato, a researcher at the University of Bern,
Physicists not involved in the experiment have been understandably
Alvaro De Rujula, a theoretical physicist at CERN, the European
Organization for Nuclear Research outside Geneva from where the
neutron beam was fired, said he blamed the readings on a so-far
undetected human error.
If not, and it's a big if, the door would be opened to some wild
possibilities.The average person, said De Rujula, "could, in principle,
travel to the past and kill their mother before they were born.
"But Ereditato and his team are wary of letting such science fiction
story lines keep them up at night.
"We will continue our studies and we will wait patiently for the
confirmation," he told the AP. "Everybody is free to do what they want:
to think, to claim, to dream."
He added: "I'm not going to tell you my dreams."