The Discovery of Gravitational Waves is Making Waves in Physics

A computer simulation shows two black holes colliding (Photo from MIT News “Scientists Make First Direct Detection of Gravitational Waves”)

Rhia Singh ’17. Over a billion years ago, millions of galaxies from the Milky Way, a pair of black holes collided losing more mass than three times the mass of the Sun. All this mass converted to energy in a fraction of a second and released as gravitational waves that rippled space itself.

A black hole is a place in space where gravitational attraction is so strong that light cannot escape making it invisible. The strong gravitational pull is caused by matter being squeezed into a tiny space. A stellar black hole can occur when a star collapses on itself creating a supernova. A black hole cannot be seen but, space telescopes with special tools can help find black holes because the special tools can see how stars that are very close to black holes react to the intense pull of gravity.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) was constructed to detect gravitational waves. On September 14, 2015, Marco Drago, a thirty-two-year-old Italian postdoctoral student and a member of the LIGO Scientific Collaboration, noticed a compressed squiggle, which if heard would sound like a faint whooping from low to high. On February 11, 2016, the LIGO team confirmed that signal was the first direct observation of gravitational waves.

Mr. Paugh and Ms. Sardo, physics teachers, explained:

“A Laser Interferometer was used to detect gravitational waves. Gravitational waves couldn’t be measured with a ruler since it was cause the ruler itself to bend. The speed of light is a constant so, very simply, by the speed it takes light to travel from one end to another end and back again should be equal. However, a gravitational wave would cause the speed of light to be different since the light would bend.”

Albert Einstein, was the first person to consider the existence of gravitational waves in his General Theory of Relativity. Simply, the theory states that gravity is produced by space and time curving in the presence of mass.

Alex Lu ‘16, a senior in the Physics Major, explained:

“If you imagine space-time as a taut blanket with a marble rolling around on it, then that marble represents a planet in orbit. If you imagine, a bowling ball in the blanket, then you can imagine the blanket curving around the bowling ball. In the case of a black hole, the mass is so massive that the blanket is warped.” When two black holes orbit each other, they stretch and squeeze space-time creating pulses or gravitational waves.

Pedro Sotomayor ‘17, a junior in the Physics Major, exclaimed that “When I found out I was ecstatic. It’s amazing to finally have proof of these waves which had been hypothesized about over a hundred years ago.” Along with offering proof of a theory, gravitational waves allow scientists a greater understanding of space.    

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