Posts Tagged ‘Faster-than-light’

Scientists Try to Explain the Fast-than-light Nutrinos

October 18, 2011

Since the apparent discovery of neutrinos that are moving at superluminal speeds, scientists have been trying to come up with explanations for these findings. The most obvious and likely explanation is measurement error.

Among the most recent ideas is a paper invoking Einstein’s supposedly challenged theory of relativity. The OPERA team used GPS satellites to accurately measure the 730-km distance between their detector and the CERN beam where the neutrinos were produced. Yet, according to special relativity, calculations will be slightly different when two observers are moving relative to one another.

Since the satellites were zipping around the Earth, the positions of the neutrino source and the detector changed. According to the paper, the movement would account for a 64 nanoseconds discrepancy, nearly exactly what the OPERA team observes.

A less likely explanation is that Einstein’s Theory of Relativity is wrong. In fact, both the theories of Special and General Relativity have been amply proved by experiments and observations. There is at least one good reason to suspect that neutrinos do not regularly travel faster than light.

One of the earliest objections to the faster-than-light interpretation came from an astrophysical observation. In 1987, a powerful supernova showered Earth with light and neutrinos. While neutrino detectors observed neutrinos arriving about three hours before the light, this was due to the lightweight particles getting a head start. Neutrinos, which hardly interact with matter, escaped the exploding stellar core with relative ease while photons, absorbed and re-emitted by the various elements, took longer to flee. If the effect from OPERA were as large as observed, scientists have calculated that the neutrinos should have arrived more than four years in advance of the light.

And we know that electrons do not travel faster than light.

Theoretical physicist Matt Strassler also noted on his blog that the Standard Model’s properties suggest that making neutrinos go faster than light requires electrons to do the same. But if electron neutrinos moved at the speed suggested by the OPERA experiment, then electrons should also travel faster than the speed of light by at least one part in 1,000,000,000, or one billionth. Experiments have established theoretical limits that electrons remain subluminal at a precision down to more than 5 part in a thousand trillion, effectively ruling this scenario out.

So, what is going on? We don’t know, yet. My opinion, which really isn’t worth much, is that if the observations are verified, than superluminal travel will be due to some unique property of the nutrinos, which are odd little particles anyway.

I suppose the consensus is measurement error. Too bad. No warp drive yet.

Faster Than Light 2

September 26, 2011
Cropped image from a larger one of Michio Kaku...

Michio Kaku

In an article in the Wall Street Journal, physicist Michio Kaku has something interesting to say about the recent experiments at CERN in which neutrinos seemed to have traveled faster than light.

The CERN announcement was electrifying. Some physicists burst out with glee, because it meant that the door was opening to new physics (and more Nobel Prizes). New, daring theories would need to be proposed to explain this result. Others broke out in a cold sweat, realizing that the entire foundation of modern physics might have to be revised. Every textbook would have to be rewritten, every experiment recalibrated.

Cosmology, the very way we think of space, would be forever altered. The distance to the stars and galaxies and the age of the universe (13.7 billion years) would be thrown in doubt. Even the expanding universe theory, the Big Bang theory, and black holes would have to be re-examined.

Moreover, everything we think we understand about nuclear physics would need to be reassessed. Every school kid knows Einstein’s famous equation E=MC2, where a small amount of mass M can create a vast amount of energy E, because the speed of light C squared is such a huge number. But if C is off, it means that all nuclear physics has to be recalibrated. Nuclear weapons, nuclear medicine and radioactive dating would be affected because all nuclear reactions are based on Einstein’s relation between matter and energy.

If all this wasn’t bad enough, it would also mean that the fundamental principles of physics are incorrect. Modern physics is based on two theories, relativity and the quantum theory, so half of modern physics would have to be replaced by a new theory. My own field, string theory, is no exception. Personally, I would have to revise all my theories because relativity is built into string theory from the very beginning.

In other words, much of what we think we know about the universe is about as accurate as views of the people back in the middle ages who believed that the Earth was the center of the universe and everything was made up of the four elements; earth, fire, air and water. Of course, the most likely outcome is that the findings at CERN are erroneous. Kaku ends his piece by declaring this to be a victory for science however it turns out.

Reputations may rise and fall. But in the end, this is a victory for science. No theory is carved in stone. Science is merciless when it comes to testing all theories over and over, at any time, in any place. Unlike religion or politics, science is ultimately decided by experiments, done repeatedly in every form. There are no sacred cows. In science, 100 authorities count for nothing. Experiment counts for everything.

So, if a theory as well established as Einstein’s Theories of Relativity can be cast into doubt, what does this say about hypotheses regarding global warming, which are based on very incomplete understandings of the Earth’s atmosphere?

I want everyone out there who believes that global warming/climate change/ climate catastrophe is settled science to repeat after me one hundred times. The science is never settled.

You can find Michio Kaku’s books here.

Faster Than Light

September 23, 2011
Tachyon visualization. Since that object moves...

Image via Wikipedia

It would seem that the physicists at CERN have detected subatomic particles moving faster than  the speed of light. This is impossible, according to Einstein’s theory of relativity. So, either we’re about to see a revolution in the way we see the universe or there is a mistake.

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.

The team presented its work so other scientists can determine if the approach 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.

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 consistently.

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.

There is good reason to believe that the speed of light is the ultimate speed limit. As any object moves faster, it gains mass. We don’t notice this because, at the speeds we move the gain is too small to be detected. As you approach the speed of light, the gain in mass is larger and larger. In order to achieve light speed the mass would increase to infinite. This is obviously impossible. This gain in mass has been detected in subatomic particles that have been accelerated to 99.99999% of the speed of light.

Scientists have speculated on particles that move faster than light called tachyons. These particles would be unable to slow down to the speed of light. Tachyons have never been detected (how would you?) and there is no good reason to suppose they exist.

But, here’s something I saw in the wikipedia article on tachyons that seems to have some relevance to this story.

In 1985 it was proposed by Chodos et al. that neutrinos can have a tachyonic nature.[7][8] Today, the possibility of having standard particles moving at superluminal speeds is a natural consequence of unconventional dispersion relations that appear in the Standard-Model Extension,[9][10][11] a realistic description of the possible violation of Lorentz invariance in field theory. In this framework, neutrinos experience Lorentz-violating oscillations and can travel faster than light at high energies.

I am going to have to work on translating that to English. Maybe this article will help.

Most likely this will turn out to be an error in measurement and I have to commend the scientists for their caution. If this turns out to be valid than maybe something like warp drive is not too far away.

Maybe not


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