The first detection of gravitational waves, a disturbance of space-time continuum that Albert Einstein predicted a century ago, has opened new ways to explore the universe.
At about 10:30 a.m. on Feb. 11, MIT, Caltech and the National Science Foundation first detected the waves in their Laser Interferometer Gravitational-Wave Observatory (LIGO), according to a press release from MIT’s president, Rafael Reif.
“Those rippling messages are imperceptibly faint; until now, they had defied direct observation. Because LIGO succeeded in detecting these faint messages – from two black holes that crashed together to form a still larger one – we have remarkable evidence that the system behaves exactly as Einstein foretold,” Reif wrote.
LIGO used an advanced telescope that relies on light to hear the collision of two black holes, which was remarkable because it was expected that black holes emit no light, Reif said.
“The effect [of the collision of two black holes] is less than the size of a proton. You need a very accurate and sensitive device to detect it,” physics professor Philip Mannheim, said.
An indirect detection of a gravity wave was found 40 years ago, Mannheim said. This was sensed when two stars were rotating around each other. They were emitting energy as they were being pulled closer together.
However, this does not produce enough radiation for us to see, Mannheim said, which is why they needed two black holes rotating around each other.
“They [LIGO] had a bit of luck,” Mannheim said. “We didn’t know if two black holes rotating around each other even existed, and they were lucky it happened while they were looking for it.”
Mannheim said that the signal LIGO picked up on was send one billion years ago, which is why it was lucky LIGO was looking at the time the signal reached us.
“We will probably see it again. I think there are lots of black holes so I am confident this is not a a one-time event,” Mannheim said.
The current LIGO program started 25 years ago and has cost over $1 billion.
Not only is this finding a validity of Einstein’s relativity theory, it has opened up a new way to explore the universe, Mannheim said.
“Most of the information about the universe is about light from stars that admit radiation. We would like to look more at the universe in other ways, such as gravity waves,” Mannheim said. “We will gradually build a deeper knowledge about how the cosmos functions.”
Mannheim said that it could be that these gravity waves were admitted during the big bang, and it is possible to pick up the earliest signals regarding how the universe came into being.
In addition to the physics aspect of the discovery, there is also knowledge gained about society.
Einstein’s theory of relativity has practical applications, Mannheim said. However, it is hard to tell if a scientific discovery will have a practical application until long after the targeted research. For example, 100 years after Einstein’s theory of relativity we were able to use it for cell phone and GPS signals.
“To me, it’s a closure to something which has had a very complicated history. The field equations and the whole history of general relativity have been complicated. Here, suddenly, we have something we can grab onto and say, ‘Einstein was right. What a marvelous insight and intuition he had,’” MIT physicist who worked at the LIGO Rainer Weiss said in an interview for MIT news.
Emma Krueger is a staff writer for The Daily Campus. She can be reached via email at firstname.lastname@example.org.