The experiment was performed by a team that includes astrophysicists at Penn State University, who used NASA's Fermi Gamma Ray Space Telescope to study particles from the explosion moving at nearly the speed of light.
The experiment confirmed aspects of Einstein's theories of gravity, which unite space and time in the concept of space-time. The team's research is published in the current online edition of the journal Nature and will be published at a later date in the print edition.
"The next major goal is to fuse quantum mechanics with gravity into a single quantum gravity theory," said Peter Meszaros, the Holder of the Eberly Family Chair in Astronomy and Astrophysics at Penn State, a Professor of Physics there, and a member of the team that did the physics experiment with the Fermi telescope. "Physicists would like to replace Einstein's vision of gravity -- as expressed in his relativity theories -- with something that handles all fundamental forces," said Peter Michelson, principal investigator of Fermi's Large Area Telescope, at Stanford University. Scientists have constructed many models to fit their ideas for the new theories, but they have few ways to test these models with physical experiments.
The opportunity to test these models occurred on 9 May 2009 at 8:23 p.m. U. S. Eastern time, when Fermi and other satellites detected the "short" gamma ray burst, designated GRB 090510, in the act of ejecting particles at 99.99995 percent of the speed of light. Astronomers say this type of explosion likely occurred in the distant galaxy during an annihilating collision between neutron stars.
Many approaches to new theories of quantum gravity picture space-time as having a shifting, frothy structure at physical scales trillions of times smaller than an electron. Some models predict that such a foamy structure would cause higher-energy gamma rays to move slightly more slowly than photons at lower energy. "Such models would violate Einstein's postulate that all electromagnetic radiation -- radio waves, infrared rays, visible light, X-rays, and gamma rays -- travel through a vacuum at the same speed," said Meszaros. "But different versions of quantum gravity predict different degrees of violation of this postulate, and we need to separate the wheat from the chaff."
Of the many gamma-ray photons detected by Fermi from the 2.1-second burst, two had energies differing by a million times. Yet after traveling some seven billion years, the pair of photons arrived just nine-tenths of a second apart. "This measurement eliminates any approach to a new theory of gravity that predicts a strong energy-dependent change in the speed of light," Michelson said. The long-distance experiment showed that "To one part in 100 million billion, these two photons traveled at the same speed. "Einstein still rules," Michelson said.
As a result of the new space experiment, Meszaros further explained, "Any viable theory of quantum gravity must be one that predicts either a weaker violation of the speed-of-light constancy than that which we measured, or none at all."
In addition to Mészáros, other Penn State scientists on the research team include Xuefeng Wu, a research associate, and Kenji Toma, a postdoctoral scholar.
[ Barbara Kennedy / Francis Reddy ]CONTACTS
Barbara K. Kennedy | EurekAlert!
Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory
SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences