Possible Relativity Violations Shed Light On Light

Light as we know it may be a direct result of small violations of relativity, according to new research scheduled for publication online Tuesday (March 22) in the journal Physical Review D.

In discussing the work, physics professor Alan Kostelecky of Indiana University described light as “a shimmering of ever-present vectors in empty space” and compared it to waves propagating across a field of grain. This description is markedly different from existing theories of light, in which scientists believe space is without direction and the properties of light are a result of an underlying symmetry of nature.

Instead the report, co-authored by Kostelecky with physics professor Robert Bluhm of Colby College, discusses the possibility that light arises from the breaking of a symmetry of relativity. “Nature’s beauty is more subtle than perfect symmetry,” Kostelecky said. “The underlying origin of light may be another example of this subtlety.”

The new results show that this description of light is a general feature of relativity violations and holds both in empty space and in the presence of gravity. “In this picture, light has a strange beauty, and its origin is tied into minuscule violations of Einstein’s relativity in a profound and general way,” Kostelecky said.

The report also points out that this new view of light can be tested experimentally by studying the properties of light and its interactions with matter and gravity. All these have behavior that is predicted to deviate from conventional expectations in tiny but important ways.

“This is an alternative, viable way of understanding light with potential experimental implications. That’s what makes it exciting,” Kostelecky said.

Possible detectable effects include asymmetries between properties of certain particles and antiparticles, and cyclic variations in their behavior as Earth rotates. The effects can be sought using various experimental equipment ranging from giant particle colliders, such as the one at Fermilab in Illinois, to “tabletop” experiments with atomic clocks or resonant cavities. A number of such experiments are now under way.

From an IU press release.

3 thoughts on “Possible Relativity Violations Shed Light On Light”

  1. You know, I have a background in physics, and somewhat more of a generalist than the average physicist, but I still have no idea what these guys are talking about. The abstract (with title “Spontaneous Lorentz Violation, Nambu-Goldstone Modes, and Gravity”) doesn’t seem to mention light specifically, for instance. And the abstract refers to “bumblebee models”, which they seem to have invented.

    Ok, having read a bit more I have a vague idea what they’re up to. Basically this is coming from the usual trouble that gravitation has with quantum theories; in this case as far as I can tell they’re considering that a quantum gravity theory of some sort may produce a local “preferred direction” – this is what violates the natural symmetries of spacetime (the Lorentz symmetries of special relativity). This preferred direction would arise “spontaneously” in a similar manner to the way the Higgs field is expected to spontaneously break the symmetry between the weak and electromagnetic forces; however I get the impression that they’re actually removing standard electrodynamics from the theory, and replacing it with natural vibrations in this local spontaneously created set of directions (vector field).

    At least, that’s as far as I could understand it – maybe somebody else has a better idea?

  2. thanks for the precis! I was trying to understand what they were talking about but didn’t really stand a chance :-)


    According to Einstein’s 1916 general theory of relativity–our present theory of gravitation–space and time are inextricably woven into a 4-dimensional fabric called spacetime, and gravity is nothing but the warping and twisting of spacetime by massive celestial bodies. Is this theory correct? Right now, NASA’s Gravity Probe B (GP-B) mission that recently completed its first year in orbit around the earth is continuing to collect data in the first controlled experiment specifically designed to answer this question.

    Launched just over a year ago, GP-B uses four spherical gyroscopes–listed in the Guinness Database of World Records as the roundest objects ever made–to test, with unprecedented precision, two extraordinary effects predicted by Einstein’s theory of gravitation: 1) the geodetic effect–the amount by which the Earth warps the local spacetime in which it resides, and 2) the frame-dragging effect–the amount by which the rotating Earth drags its local spacetime around with it. The four gyroscopes are housed inside a pristine cryogenic space-borne laboratory, specifically designed to eliminate or at least minimize all possible sources of external disturbance and noise. Within this chamber, which is maintained at a vacuum 100 times greater than that of outer space and at a temperature just 1.8 degrees above absolute zero, the four GP-B science gyroscopes spin in complete isolation–their spin axes affected only by the relativistic warping and twisting of Earth’s local spacetime.

    While these warping and twisting effects of gravity are calculated to be enormous in the neighborhood of ultra-massive celestial bodies such as black holes, they are minuscule and extremely difficult to measure in the vicinity of a tiny celestial object such as our Earth. Since 1916, various tests of general relativity–including two suggested by Einstein himself, and made within his lifetime–suggest that he was on the right track. However, in most previous tests, the relativity signals had to be extracted from a significant level of background noise, whereas in the GP-B experiment, the background noise has been systematically eliminated or reduced to insignificant levels, so the relativity signals can be clearly detected. Thus, GP-B promises to yield results several orders of magnitude more accurate than those of previous observational tests.

    Gravity is a fundamental force in nature; it affects all of us all the time, but it is still somewhat an enigma. With the general theory of relativity, Einstein forever changed our notions of space, time, and gravity. And although it has become one of the cornerstones of modern physics, general relativity remains the least tested of Einstein’s theories.

    When GP-B finishes the science (data collection) phase of the mission this summer, project scientists will have collected over 10 months of hard data, which when analyzed over the coming year, will tell us–to a very high level of accuracy–whether or not these two important postulates of general relativity are correct. Such rigorous experimental verification is essential to furthering our understanding of the nature of our universe, particularly about massive objects in space, such as black holes and quasars.

    As GP-B Physicist, John Mester, puts it, “General relativity is our current theory of gravitation, and it has wide ranging implications for our understanding of the structure of the cosmos. At present, Einstein’s theory of gravitation lies outside the other three forces of nature (the strong force, the weak force, and the electromagnetic force), which are explained within a unified framework called The Standard Model. Attempts to unify all four forces of nature have eluded physicists from Einstein to the current day. Testing theories to high precision will help define their range of validity or reveal where these theories break down.” GP-B Program Manager, Gaylord Green adds: “Physics is an experimental science. If a theory is not tested, it becomes a philosophy, not physics.”

    Just over one year ago, on April 20, 2004, GP-B was launched into a nearly perfect polar orbit from Vandenberg Air Force Base, Calif. atop a Boeing Delta II launch vehicle. During a four-month initialization phase, the spacecraft underwent a complete checkout and optimization of all systems. Over 10,000 commands were successfully executed by on-board computers. The four gyroscopes were spun up to their final speeds, averaging 72 Hz (4,300 rpm) and their spin axes were aligned with the GP-B guide star (IM Pegasi/HR 8703). On August 28, 2004, the GP-B team began the 10+ month science phase of the mission, collecting data on the changing spin axis orientation of the four gyros that will ultimately confirm or disprove the geodetic and frame-dragging predictions of general relativity.

    It is fitting that the science phase of the GP-B experiment, the most rigorous test to date of general relativity, will be completed this year–the 100th anniversary of Einstein’s “miracle” year, in which he published four seminal papers, including the special theory of relativity and his paper on the production and transformation of light, for which he was awarded the Nobel Prize in 1921. “The GP-B team has shown that through hard work and sustained effort, great things can be accomplished”, said Tony Lyons, NASA’s GP-B program manager at the Marshall Spaceflight Center (MSFC) in Huntsville, AL. “The spacecraft keeps getting better as we get farther into the mission, and that’s a tribute to the hard work of our excellent team.”

    Just past the one-year mark, the spacecraft continues to perform exceptionally well. The four on board gyroscopes have now experienced and measured relativistic effects for eight months. The GP-B team is currently in the process of updating their measurement of the amount of liquid helium remaining in the spacecraft’s Dewar, a cement-mixer sized Thermos vessel that maintains the cryogenic environment for the probe. Shortly before the helium runs out, the team plans to perform an important series of instrument calibrations. “The purpose of the calibration phase is to ensure data accuracy and analysis integrity prior to releasing results,” says Mac Keiser, project chief scientist.

    So, was Einstein correct? Mac Keiser is not saying. Project policy maintains that the program will not release any scientific results obtained during the mission until after the data analysis is completed–sometime in the summer of 2006.

    More information about Gravity Probe B is available at:

Comments are closed.