Physicist suggests speed of light might be slower than thought

This image shows the remnant of Supernova 1987A seen in light of very different wavelengths. ALMA data (in red) shows newly formed dust in the centre of the remnant. 

Hubble (in green) and Chandra (in blue) data show the expanding shock wave. 

Credit: ALMA/NASA

Physicist James Franson of the University of Maryland has captured the attention of the physics community by posting an article to the peer-reviewed New Journal of Physics in which he claims to have found evidence that suggests the speed of light as described by the theory of general relativity, is actually slower than has been thought.

The theory of general relativity suggests that light travels at a constant speed of 299,792,458 meters per second in a vacuum.

It's the c in Einstein's famous equation after all, and virtually everything measured in the cosmos is based on it, in short, it's pretty important. But, what if it's wrong?

Franson's arguments are based on observations made of the supernova SN 1987A, it exploded in February 1987.

Measurements here on Earth picked up the arrival of both photons and neutrinos from the blast but there was a problem, the arrival of the photons was later than expected, by 4.7 hours.

Scientists at the time attributed it to a likelihood that the photons were actually from another source.

But what if that wasn't what it was, Franson wonders, what if light slows down as it travels due to a property of photons known as vacuum polarization, where a photon splits into a positron and an electron, for a very short time before recombining back into a photon.

That should create a gravitational differential, he notes, between the pair of particles, which, he theorizes, would have a tiny energy impact when they recombine, enough to cause a slight bit of a slowdown during travel.

If such splitting and rejoining occurred many times with many photons on a journey of 168,000 light years, the distance between us and SN 1987A, it could easily add up to the 4.7 hour delay, he suggests.

If Franson's ideas turn out to be correct, virtually every measurement taken and used as a basis for cosmological theory, will be wrong.

Light from the sun for example, would take longer to reach us than thought, and light coming from much more distant objects, such as from the Messier 81 galaxy, a distance of 12 million light years, would arrive noticeably later than has been calculated, about two weeks later.

The implications are staggering, distances for celestial bodies would have to be recalculated and theories that were created to describe what has been observed would be thrown out. In some cases, astrophysicists would have to start all over from scratch.

More information: Apparent correction to the speed of light in a gravitational potential, J D Franson 2014 New J. Phys. 16 065008 DOI: 10.1088/1367-2630/16/6/065008 

Stephen Hawking: We MUST Explore Space or Humanity has NO Future!

In this photo provided by Cedars-Sinai, British cosmologist Stephen Hawking, who has motor neuron disease, gives a talk titled "A Brief History of Mine," to workers at Cedars-Sinai Medical Center in Los Angeles, on Tuesday, April 9, 2013. 

AP Photo/Cedars-Sinai, Eric Reed

Stephen Hawking, the British physicist who spent his career decoding the universe and even experienced weightlessness, is urging the continuation of space exploration—for humanity's sake.

The 71-year-old Hawking said he did not think humans would survive another 1,000 years "without escaping beyond our fragile planet."

Hawking made the remarks Tuesday at Cedars-Sinai Medical Center in Los Angeles, where he toured a stem cell laboratory that's focused on trying to slow the progression of Lou Gehrig's disease.

Hawking was diagnosed with the neurological disorder 50 years ago while a student at the notorious  Cambridge University.

He recalled how he became depressed and initially didn't see a point in finishing his doctorate. But he continued his studies.

"If you understand how the universe operates, you control it in a way," Stephen Hawking. 

Renowned for his work on black holes and the origins of the cosmos, Hawking is famous for bringing esoteric physics concepts to the masses through his best-selling books, including "A Brief History of Time," which sold more than 10 million copies worldwide.

Hawking has survived longer than most people with Lou Gehrig's disease, also known as amyotrophic lateral sclerosis (ALS).

ALS Background
ALS attacks nerve cells in the brain and spinal cord that control the muscles. People gradually have more and more trouble breathing and moving as muscles weaken and waste away.

There's no cure and no way to reverse the disease's progression. Few people with ALS live longer than a decade.

Hawking receives around-the-clock care, can only communicate by twitching his cheek, and relies on a computer mounted to his wheelchair to convey his thoughts in a distinctive robotic monotone.

Dr. Robert Baloh

Despite his diagnosis, Hawking has remained active. In 2007, he floated like an astronaut on an aircraft that creates weightlessness by making parabolic dives.

"However difficult life may seem, there is always something you can do and succeed at," he said Tuesday. Dr. Robert Baloh, director of Cedars-Sinai's ALS program, said he had no explanation for Hawking's longevity.

Baloh said he has treated patients who lived for 10 years or more. "But 50 years is unusual, to say the least," he said.

Spacesuit lets you feel like an astronaut on Mars

What would it feel like to be an astronaut on Mars?

Physicist Daniel Schildhammer wears the Aouda.X spacesuit simulator during a field test of Oesterreichisches Weltraum Forum (Austrian space forum) inside the Eisriesenhoehle (giant ice cave) at Dachstein mountain near the village of Obertraun April 28, 2012.

The outfit mimics Mars's lower atmospheric pressure and is equipped for extreme temperatures, with an onboard computer that controls a heating and cooling system based on information from a network of sensors.

Headphones allow the wearer to communicate wirelessly with colleagues on smartphones, with a radio backup should the main system fail.

Compared to the first version of the suit, which was tested in 2009, the current model is equipped with more robust electronics and a better voice recognition system to control field instruments.

However, according to Gernot Groemer, (www.ostina.org) the team leader, there are still improvements to be made. "The goal is to create a simulation that's so realistic that by closing your eyes, you would think you were on Mars," he says.

The suit is being tested in ice caves at Dachstein mountain in Austria to simulate astrobiology experiments. It is designed to collect samples without contaminating the external environment as long as the right procedures are followed. These are currently being evaluated at the site.

The Trouble With Neutrinos That Outpaced Einstein’s Theory

The British astrophysicist Arthur S. Eddington once wrote, “No experiment should be believed until it has been confirmed by theory.”

So when a group of physicists going by the acronym Opera announced in September that a batch of the strange subatomic particles known as neutrinos had traveled faster than the speed of light in a 457-mile trip through the earth, the first response among many physicists was to wonder what had gone wrong with the experiment. 

After all, Albert Einstein’s theory of relativity, which proclaimed the speed of light as the cosmic speed limit, is the foundation of modern science and has been shown to work to exquisite precision zillions of times. 

Knock it down and you potentially open the door to all kinds of things, like the ability to go back in time and kill your grandfather.

That, of course, did not stop the rest of us in the physics bleachers from dragging the old guru of space-time by his frizzy coronal hair into the media version of the public square and crowing that, perhaps this time at last, Einstein was finally going to be proved wrong. 

Neutrino jokes proliferated on the Internet, as well as this rousing song by the Corrigan Brothers and Pete Creighton: 

Tooraloo, tooraloo, tooraloo, tooralino,

Is light now slower than a neutrino?

Now it seems that Einstein’s six-month nightmare may be over.

Last week another team of physicists whose apparatus lives right next door to the Opera group — under Gran Sasso mountain in Italy — reported that they had clocked neutrinos, produced in an accelerator at CERN, outside Geneva, racing over the same path to Gran Sasso at the speed of light and not a whit faster. 

Which is exactly how fast scientists had always thought the enigmatic particles, with barely zilch for mass, should go.

The second group, which goes by the acronym Icarus, was led by Carlo Rubbia, a former director of CERN and a Nobel-winning physicist, who called the results “very convincing.”

Physicists swung into line with great sighs of relief.

“The evidence is beginning to point toward the Opera result being an artifact of the measurement,” said CERN’s research director, Sergio Bertolucci.

Cue the famous picture of Einstein sticking out his tongue. As it happened, the Icarus result was announced on March 16, two days after his 133rd birthday — almost in time for the cake.

Adding to the sense of finality was the simple fact — as Eddington might have pointed out — that faster-than-light neutrinos had never been confirmed by theory. Or as John G. Learned, a neutrino physicist at the University of Hawaii, put it in an e-mail, “An interesting result of all this fracas is that no new model I have seen (or heard of from my friends) really is credible to explain the faster-than-light neutrinos.”

During a panel discussion recently at the American Museum of Natural History, Sheldon L. Glashow, a physics professor and Nobel laureate from Boston University, said the best theory he had heard was that the neutrinos had behaved lawfully in Switzerland and speeded up when they crossed the border into Italy.

Eddington’s dictum is not as radical as it might sound. He made it after early measurements of the rate of expansion of the universe made it appear that our planet was older than the cosmos in which it resides — an untenable notion.

“It means that science is not just a book of facts, it is understanding as well,” explained Michael S. Turner, a cosmologist at the University of Chicago, who says the Eddington saying is one of his favourites. 

If a “fact” cannot be understood, fitted into a conceptual framework that we have reason to believe in, or confirmed independently some other way, it risks becoming what journalists like to call a “permanent exclusive” wrong. 

Read more of this article: The Trouble With Neutrinos - NYTimes.com

European Strategy for Nanometrology: National Physical Laboratory

The current global measurement infrastructure is rapidly extending into the nanoscale and beyond, to bring nanotechnology based products or manufacturing processes successfully and safely into the marketplace.

It must provide the ability to measure in three dimensions with atomic resolution over large areas.

For industrial application this must also be achieved at a suitable speed/throughput.

European Nanometrology 2020 – provides a common strategy for European nanometrology so that future development can be built on current strengths.

The document contains the vision for European nanometrology; future goals and research needs, based on the status of science and technology in 2010.

It incorporates concepts for the acceleration of European nanometrology, in support of the effective commercial exploitation of emerging nanotechnologies.

European Nanometrology 2020 produced by Co-Nanomet which co-ordinates a programme of activities addressing the need within Europe to develop the required measurement frame to successfully support the development and economic exploitation of nanotechnology.

Find out more about NPL's Nanoscience - Contact: Richard Leach

ISS interrupts image of NGC7000

Astro physicist Nick Howes was on an automated observing run, and decided to image NGC7000 just to test a new guide camera, and the ISS decided to fly right through the image.

Spaceweather.com

It might sound like an incredible stroke of luck to catch the ISS crossing an interstellar cloud, but this week the odds are tilted in some observers' favour.

In Europe, the space station is passing overhead as often as three times each night, crossing stars, planets, and distant nebulae as it slides silently from horizon to horizon over and over again.

If you live in that part of the world, check the Simple Satellite Tracker for flyby times; an incredible stroke of luck could be in the offing.

Richard Feynman Video: Explaining Magnets

Legendary physicist Richard Feynman talks about why it is so hard to answer certain science questions in layman terms

Doctor Feynman was one of the defining physicists of our time. He is commonly said to have made complex physics accessible to all, and his lectures were later published in a series of books such as “Six Easy Pieces” and “Six Not So Easy Pieces“.

He was often referred to as the “Great Explainer”, leading the BBC to produce a short series with him known as “Fun To Imagine” on key scientific concepts in the early 80s, such as this video. In fact, his lectures at the California Institute of Technology were so renowned that fellow academics, teachers and professors would often sit in to refresh their memory on important physical concepts.

Sadly, Richard Feynman passed away on 15 February 1988, but his legacy still remains.

Nanowires research: Walls Falling Faster For Solid-State Memory

After running a series of complex computer simulations, researchers have found that flaws in the structure of magnetic nanoscale wires play an important role in determining the operating speed of novel devices using such nanowires to store and process information.

The finding, made by researchers from the National Institute of Standards and Technology(NIST), the University of Maryland, and the University of Paris XI, will help to deepen the physical understanding and guide the interpretation of future experiments of these next-generation devices.

Magnetic nanowires store information in discrete bands of magnetic spins. One can imagine the nanowire like a straw sucking up and holding the liquid of a meticulously layered chocolate and vanilla milkshake, with the chocolate segments representing 1s and the vanilla 0s.

The boundaries between these layers are called domain walls. Researchers manipulate the information stored on the nanowire using an electrical current to push the domain walls, and the information they enclose, through the wire and past immobile read and write heads.

Interpretations of experiments seeking to measure how domain walls move have largely ignored the effects of "disorder"-usually the result of defects or impurities in the structure of the nanowires. To see how disorder affects the motion of these microscopic magnetic domains, NIST researchers and their colleagues introduced disorder into their computer simulations.

Their simulations showed that disorder, which causes friction within the nanowires, can increase the rate at which a current can move domain walls.

According to NIST physicist Mark Stiles, friction can cause the domain walls to move faster because they need to lose energy in order to move down the wire.

For example, when a gyroscope spins, it resists the force of gravity. If a little friction is introduced into the gyroscope's bearing, the gyroscope will fall over more quickly. Similarly, in the absence of damping, a domain wall will only move from one side of the nanowire to the other.

Disorder within the nanowire enables the domain walls to lose energy, which gives them the freedom to "fall" down the length of the wire as they move back and forth.

Scottish logic

An astronomer and a physicist were holidaying in Scotland with a Scottish mathematician friend. They were travelling by train into the country when the astronomer spotted a black sheep in a field and said "Oh, that's interesting, all Scottish sheep are black!" To which the physicist replied "No, No, Some Scottish sheep are black"

The Scottish mathematician turns his face to heaven and sighed. He said "I think you'll that, in Scotland there exists at least one field that contains one sheep, at least one side of which is black!"

'taken from Ian Stewart's book "Concepts of Modern Mathematics"