Scientists from Penn State University and the Chinese Academy of Sciences have discovered a new way to test one of the key tenants of Einstein’s theory of General Relativity that they claim is between 10 and 100 times better than previous testing methods.
The new technique replaces techniques that utilized gamma-ray bursts with a new method which uses Fast Radio Bursts, extremely short blasts of energy that last only a few milliseconds and are likely caused by mysterious phenomenon occurring beyond the edge of the Milky Way, the team explains in research published this week in the journal Physical Review Letters.
The paper—which according to a press release was given “Editor’s Suggestion” honors from the journal for its “its particular importance, innovation, and broad appeal”—will be essential when it comes to analyzing the abundance of Fast Radio Bursts that advanced radio-signal observatories currently in the planning stages will be able to detect, according to the study’s authors.
“With abundant observational information in the future, we can gain a better understanding of the physical nature of Fast Radio Bursts,” said senior author Peter Mészáros, the Eberly Family Chair in Astronomy and Astrophysics and Professor of Physics at Penn State.
As is the case with other forms of electromagnetic radiation, Fast Radio Bursts make their way through space in the form of photon particle waves, and the number of wave crests arriving per second (also known as frequency) are in the same range as radio signals, Mészáros noted.
“When more-powerful detectors provide us with more observations, 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 study author added.
A ‘significant tribute’ to Einstein’s Equivalence Principle
As more of these bursts are observed, and provided their origins can be pinpointed, their impact is expected to increase significantly, the researchers explained. If they can be proved to originate from beyond the Milky Way and their distances can be precisely measured, they could provide a new, more powerful tool for putting Einstein’s Equivalence Principle to the test.
Einstein’s Equivalence Principle basically states that any pair of photons of different frequencies emitted at the same time, from the same source, and passing through the same gravitational fields should arrive at their destination at exactly the same time. If this is correct, any differences in the time it takes photons to reach Earth should not be due to gravitational fields they encounter.
“By measuring how closely in time the two different-frequency photons arrive, we can test how closely they obey Einstein’s Equivalence Principle,” said Mészáros. The technique his team came up with compares the amount of curvature the photons experienced due to massive objects on or close to the past they travel through space.
While they have only been able to study a handful of Fast Radio Bursts, they found that the ones they’ve analyzed so far “supersedes by one to two orders of magnitude the previous best limits on the accuracy of the Einstein Equivalence Principle,” the Penn State professor explained. “Our analysis using radio frequencies shows that the Einstein Equivalence Principle is obeyed to one part in a hundred million. This result is a significant tribute to Einstein’s theory.”
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Feature Image: An artist concept drawing of a magnetar, one of the proposed sources of a fast radio burst.
Credit: NASA
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