Chuck Bednar for redOrbit.com – @BednarChuck
Using NASA’s Chandra X-ray Observatory and other space-and ground-based telescopes, a team of researchers has conducted observations of some of the most distant known galaxies in the universe to better understand the very nature of space and time.
As part of their research, they focused on a tiny and extremely unusual theoretical feature of the universe – one that is too small to be seen directly, according to Space.com. Known as “quantum foam,” this phenomenon is believed to cause rough patches along the route by which light travels to the Earth from distant galaxies.
Some models have suggested that the effects of this foam could be witnessed in a large group of photons that travel extremely long distances, so to better understand it, a team of scientists led by Eric Perlman of the Florida Institute of Technology studied some of the brightest galaxies in the known universe and managed to set new limits on the quantum nature of space-time.
Perlman’s team used Chandra, the Fermi Gamma-ray Space Telescope and VERITAS (the Very Energetic Radiation Imaging Telescope Array), and while they were unable to find any evidence of the foam itself, they were able to eliminate two theories pertaining to its behavior.
Eliminating all but one model of space-time foam
According to the researchers, whose findings have been published in The Astrophysical Journal, the predicted scale of quantum foam is roughly ten times one-billionth of one-trillionth of the diameter of the nucleus of a hydrogen atom, which explains why it cannot be detected directly.
If space-time does have a foam-like structure, however, it would limit the accuracy with which distances could be measured due to fluctuations that occur when light travels through quantum bubbles. Based on the space-time model that is used, these uncertainties should accumulate at different rates as light travels over vast stretches of the cosmos.
They used observations of X-rays and gamma rays from very distant quasars to test out various models of space-time foam, predicting that the accumulation of uncertainties would cause image quality to degrade to the point that objects would be undetectable. The wavelength at which the image vanished should depend on the model of space-time foam used, they added.
Based on their research, they were able to rule out a model, claiming that photons diffused randomly through space-time foam much like light diffuses through fog, as well as a second one known as the holographic model. They concluded that space-time is less foamy than predicted by some models, and is smooth to distances 1000 times smaller than a hydrogen atom nucleus.
That leaves one model of quantum foam still in play, according to Space.com – a model that predicts that distortion effects are not be amplified over long distances. This model suggests that evidence of quantum foam will not be found by observing distant quasars.
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