Gravitational waves can reveal existence of hidden dimensions

Studying gravitational waves – ripples in the fabric of spacetime which were first predicted by Albert Einstein more than 100 years ago – may help scientists unveil hidden dimensions.

In 1916, Einstein showed that massive accelerating objects, such as black holes orbiting one another, would disrupt spacetime in such a way that it would create waves travelling at the speed of light through the universe.

These waves would carry crucial information about the origins of galaxies and black holes within them, but also about the nature of gravity itself.

In early 2016, scientists confirmed Einstein's theory when they announced that they had managed to detect gravitational waves for the first time. The discovery opened a new window into the history and evolution of the universe.

In a study now published in the Journal of Cosmology and Astroparticle Physics, scientists have shown that they can use gravitational waves not only as an observational tool to track down black holes and other celestial objects, but also to identify potential extra dimensions in space, as they continue to learn more about gravity, and about the way these ripples behave.

Understanding gravity

"Compared to the other fundamental forces such as electromagnetism, gravity is extremely weak," explains Dr. David Andriot, one of the authors of the study.

This may be because gravity interacts with more dimensions than the three dimensions in space and the one dimension in time that are part of our daily experience.

In their paper, the scientists show how the existence of extra dimensions would affect gravitational waves - they would modify the way "standard" gravitational waves stretch and shrink spacetime and would cause additional waves at high frequencies above 1000 Hz.

Scientists have been looking for extra dimensions for years, to no avail. Their hope is that if they could detect these phenomenon on gravitational wave detectors, this might allow them to gather experimental evidence of these hidden dimensions.

At present it is unlikely that they will be able to do observe frequencies above 1000 Hz, since the existing ground-based gravitational wave detectors are not sensitive enough at high frequencies. However, it may be possible to observe changes in the way standard gravitational waves distort the spacetime fabric by using more than one detector.

The Virgo detector will join the two LIGO detectors soon for the next observation session of gravitational waves, so there's a chance this might happen sometime at the end of 2018 or beginning of 2019.