Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Mysterious radio signals from space are much better test of Einstein's General Relativity


A new way to test one of the basic principles underlying Einstein's theory of General Relativity using brief blasts of rare radio signals from space called Fast Radio Bursts is ten times, to one-hundred times better than previous testing methods that used gamma-ray bursts, according to a paper just published in the journal Physical Review Letters. The paper received additional highlighting as an "Editor's Suggestion" due to "its particular importance, innovation, and broad appeal," according to the journal's editors.

The new method is considered to be a significant tribute to Einstein on the 100th anniversary of his first formulation of the Equivalence Principle, which is a key component of Einstein's theory of General Relativity. More broadly, it also is a key component of the concept that the geometry of spacetime is curved by the mass density of individual galaxies, stars, planets, and other objects.

This illustration shows how two photons, one at a high frequency (nu_h) and another at a low frequency (nu_l), travel in curved space-time from their origin in a distant Fast Radio Burst (FRB) source until reaching the Earth. A lower-limit estimate of the gravitational pull that the photons experience along their way is given by the mass in the center of the Milky Way Galaxy.

Credit: Purple Mountain Observatory, Chinese Academy of Sciences

Fast Radio Bursts are super-brief blasts of energy -- lasting just a few milliseconds. Until now, only about a dozen Fast Radio Bursts have been detected on Earth. They appear to be caused by mysterious events beyond our Milky Way Galaxy, and possibly even beyond the Local Group of galaxies that includes the Milky Way. The new technique will be important for analyzing the abundance of observations of Fast Radio Bursts that advanced radio-signal observatories, now being planned, are expected to detect.

"With abundant observational information in the future, we can gain a better understanding of the physical nature of Fast Radio Bursts," said Peter Mészáros, Holder of the Eberly Family Chair in Astronomy and Astrophysics and Professor of Physics at Penn State, the senior author of the research paper. Like all other forms of electromagnetic radiation including visible light, Fast Radio Bursts travel through space as waves of photon particles.

The number of wave crests arriving from Fast Radio Bursts per second -- their "frequency" -- is in the same range as that of radio signals. "When more-powerful detectors provide us with more observations," Mészáros said, "we also will be able to use Fast Radio Bursts as a probe of their host galaxies, of the space between galaxies, of the cosmic-web structure of the universe, and as a test of fundamental physics."

The impact of the new method using Fast Radio Bursts is expected to increase significantly as more of the bursts are observed, and if their origin can be established more firmly. "If Fast Radio Bursts are proven to originate outside the Milky Way Galaxy, and if their distances can be measured accurately, they will be a new powerful tool for testing Einstein's Equivalence Principle and for extending the tested energy range down to radio-band frequencies," Mészáros said.

Einstein's Equivalence Principle requires that any two photons of different frequencies, emitted at the same time from the same source and traveling through the same gravitational fields, should arrive at Earth at exactly the same time.

"If Einstein's Equivalence Principle is correct, any time delay that might occur between these two photons should not be due to the gravitational fields they experienced during their travels, but should be due only to other physical effects," Mészáros said. "By measuring how closely in time the two different-frequency photons arrive, we can test how closely they obey Einstein's Equivalence Principle."

More specifically, Mészáros said the test that he and his coauthors developed involves an analysis of how much space curvature the photons experienced due to massive objects along or near their path through space. He said, "Our test of Einstein's Equivalence Principle using Fast Radio Bursts consists of checking by how much does a parameter -- the gamma parameter -- differ for the two photons with different frequencies."

Mészáros said his research team's analysis of the less-than-a-dozen recently detected Fast Radio Bursts "supersedes by one to two orders of magnitude the previous best limits on the accuracy of the Einstein Equivalence Principle," which were based on gamma rays and other energies from a 1987 supernova explosion, supernova 1987A. "Our analysis using radio frequencies shows that the Einstein Equivalence Principle is obeyed to one part in a hundred million," Mészáros said. "This result is a significant tribute to Einstein's theory, on the hundredth anniversary of its first formulation."


In addition to Mészáros, other authors of the paper include Jun-Jie Wei, a graduate student at the Purple Mountain Observatory of the Chinese Academy of Sciences; and two scientists who received their postdoctoral training with Mészáros at Penn State and who now hold academic and research positions in China, He Gao and Xue-Feng Wu, who is the paper's corresponding author.

This research is supported, in part, by the National Basic Research Program of China (2014CB845800 and 2013CB834900); NASA, the National Aeronautics and Space Administration of the United States (NNX 13AH50G), the National Natural Science Foundation of China (11322328 and 11433009), and the Chinese Academy of Sciences (2011231 and XDB09000000).


Barbara Kennedy (PIO):, (+1) 814-863-4682


This press release will be archived at (likely on or after 4 January 2015)

Media Contact

Barbara K. Kennedy


Barbara K. Kennedy | EurekAlert!

More articles from Physics and Astronomy:

nachricht Sharpening the X-ray view of the nanocosm
23.03.2018 | Changchun Institute of Optics, Fine Mechanics and Physics

nachricht Drug or duplicate?
23.03.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>