Gravitational waves are disturbances in the fabric of spacetime. It takes massive, cataclysmic events to make waves large enough for us to detect.
Last year’s discovery of gravitational waves coming from two colliding neutron stars was groundbreaking.
Prof. Daniel Holz said, “This is the very first time we’ve been able to detect sources simultaneously in both gravitational and light waves. This provides an entirely new and exciting probe, and we’ve been learning all sorts of interesting things about the universe.”
However, it didn’t provide extra dimensions to our understanding of the universe. There are only four dimensions that we know of: three spatial dimensions and the fourth dimension of time.
Until recently, gravitational waves were entirely theoretical, just like extra dimensions.
Last year three physicists won the Nobel Prize because of the first-ever detection of gravitational waves in 2015. The reason behind those waves was two black holes colliding together.
Astronomers from the University of Chicago found no evidence for extra spatial dimensions to the universe based on the gravitational wave data, reports phys.org. Their research, published in the Journal of Cosmology and Astroparticle Physics, is one of many papers in the wake of the extraordinary announcement last year that LIGO had detected a neutron star collision.
Graduate student Maya Fishbach, a co-author on the paper said, “Scientists have proposed all kinds of theories to explain dark matter and dark energy, and “a lot of alternate theories to general relativity start with adding an extra dimension. One theory is that over long distances, gravity would “leak” into the additional dimensions. This would cause gravity to appear weaker, and could account for the inconsistencies.”
Gravitational waves and light from the collision of neutron stars detected last year offered one way for Holz and Fishbach to test this theory. If gravity were leaking into other dimensions along the way, then the signal they measured in the gravitational wave detectors would have been weaker than expected. But it wasn’t.
All of the gravitational waves that we’ve detected so far match our expectations about the strength of gravity. Even gravity that’s been stretched over hundreds of millions of light-years.
But this is just the beginning, scientists said. “There are so many theories that until now, we didn’t have concrete ways to test,” Fishbach said. “This changes how a lot of people can do their astronomy.”
“We look forward to seeing what gravitational-wave surprises the universe might have in store for us,” Holz said.
Thumbnail Image Credit: Courtesy of NASA’s Goddard Space Flight Center CI Lab