As if he needed it, earlier this month scientists strengthened the proof for Einstein’s Theory of General Relativity even further with the discovery of gravitational waves.
Sanjeev Seahra, an associate professor of mathematics at the University of New Brunswick, gave a lecture last week about the discovery and what this means.
For him, it’s almost like having a new telescope.
“It’s a totally new way of looking at the universe.”
Discovered by the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration and Virgo Collaboration on Feb. 11, gravitational waves were first predicted back in 1916.
The basic premise of gravitational waves is, like ripples in water, two large enough objects rotating around each other will warp spacetime and send waves propagating through the universe.
While any object, including earth, will warp spacetime, the size does matter when it comes to our ability to detect these waves. What the Advanced LIGO detectors observed was the merging of two black holes.
The reason why Seahra said gravitational waves are like the new telescope is because where before light was our main tool of observing the universe, gravitational waves tells us new information.
“It’s an entirely different radiation, it’s ripples in spacetime. It’s not light. It has completely different characteristics. It’s made by different things, it shows us different things,” Seahra said.
“We can get direct gravitational waves information from the early universe, that with light we can’t. The early universe is opaque to electromagnetic radiation whereas gravitational radiation can just go through that.”
As the gravitational waves move through the universe, they stretch and squeeze the objects in spacetime.
While some models on the Internet exaggerate this phenomena, Seahra said change in four-kilometre-long LIGO arms that were used for detection were 1/1000th the size of a proton.
An oversimplification of how the scientists were able to detect the gravitational waves is they had two beams of light that when reconstructed were supposed to give a value of zero, but because of the slight stretching from the gravitational waves, the crests and troughs from the waves did not meet up perfectly giving an value that wasn’t zero.
One of the ways Seahra said this will affect his research is by potentially using gravitational waves to search for extra dimensions.
He said depending on how many dimensions our universe is made up of gravitational waves will act differently, so by using gravitational waves we might be able to detect whether we live in four dimensions or five.
While the news about the detection was exciting news for physicists and science lovers the world over, it was expected.
They had been some indirect evidence before that gravitational waves existed and according to Seahra, if there had not been detection scientists would have had to re-examine the validity of Einstein’s theory.
“There would have been wiggle room,” Seahra said. “But fortunately we’re not in that situation.”
While before there might have been half a class dedicated to gravitational waves in the introductory General Relativity class, Seahra said he expects that will be expanding in the near future.
