New Discoveries Shed Light on Scientific Mysteries of Gravity

Elizabeth Saunders, Copy Editor

It seems like the phrase “gravitational waves” has been everywhere in the news for the past month or so. But what are gravitational waves? The New York Times defines them as “ripples in the fabric of space-time.”

Thank you, New York Times, for a definition that sounds like complete gibberish to the 99% of the population who aren’t physicists.

Gravitational waves were first hypothesized by Einstein in his general theory of relativity. It’s taken over 100 years, but scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) recently announced that they have finally observed evidence of their existence on September 14, 2015 at 5:51am; and that evidence is just a tiny chirp.

So say that space is represented by a trampoline, and anything with mass is represented by a bowling ball. When you put the bowling ball on that trampoline, the trampoline surrounding it is going to be distorted. That’s what mass does to spacetime; it distorts it.

Now imagine that there’s another, significantly smaller object on the trampoline just a few inches from the bowling ball. Because of the distortion caused by the bowling ball, that object is going to fall towards the center of the bowling ball. According to The Telegraph, that’s how scientists think gravity works; since Earth creates a large distortion in the spacetime around it, all of the objects in its immediate vicinity—including people—fall towards its center.

That’s true when one of the masses is significantly smaller than the other. But what happens who two huge masses come near one another? Like, say, two black holes? According to The Independent, when these two objects come close enough, they start rotating around one another. Their acceleration creates ripples analogous to ones that can be seen when a pebble is dropped into a pond. These ripples are gravitational waves.

The New York Times reported that the gravitational waves that scientists were recently able to detect were the result of two black holes colliding a billion light years away. The instruments used to detect these gravitational waves convert the waves into sounds. In the case of these extremely massive black holes colliding, the instrument made only a tiny chirp, which just goes to show how difficult it is to detect these gravitational waves.

Like light waves, gravitational waves are hypothesized to be made up of a sort of particle. In light, this is called a photon. For gravitational waves, this particle is called a graviton. If gravitational waves were tricky to discover, then the graviton will be extremely difficult to find since gravity is so weak. The existence of gravitons is just one of many questions that scientists must now explore following the discovery of gravitational waves.

Scientists are heartened by this major discovery. In the words of Brebeuf physics teacher Mr. Rott, “It’s amazing that the theory that actually predicted [gravitational waves] was presented over 100 years ago, and it’s only now that we have the technology to prove it. The fact that it aligns so closely with what Einstein said just goes to show how brilliant of a theory it is. I’m very excited to see what the future holds.”

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