September 25, 2023

Setting the record straight: Gravitational Waves


This archived article was written by: Nathaniel Woodward

A benefit of the interconnectedness we share in the world with the advent of the internet and television is the opportunities we have to learn of the groundbreaking advances our specie are making. A few years ago, we discovered the theoretical “God” particle, the Higgs Boson which turned physics on its head, yet today, most couldn’t explain its most basic tenants let alone why it matters that we found it.
Early in February, news broke that the twin-research stations of LIGO or Laser Interferometer Gravitation-Wave Observatory had detected something called gravitational waves, or ripples in the fabric of space and time. Great, so what exactly does that mean? Over 100 years ago, Albert Einstein theorized in a paper on the nature of spacetime differing greatly from the established and accepted principles of Isaac Newton which stated that gravity was a force acting outwardly on the universe. Einstein’s theory of relativity suggested that gravity was not in itself a force, but a curvature of space and time, or matter telling space how to curve and space telling matter how to move.
This theory proposed the possibility that gravity could be warped and moved much like the ripples on a pond when you drop a stone in… ripples moving at the speed of light across space affecting its dimension of time as it passed by. Space is a difficult concept to grasp since we view it as essentially nothing, or empty, save the few lonely objects “floating” around in it. Gravitational waves reverse that thinking as we now know that when two objects interact, they distort the fabric of spacetime around them. If they interact “hard” fast enough, they can send out gravitational ripples throughout the fabric affecting time across a great distance.
How LIGO detected gravitational waves took a Herculean feat of engineering where in the U.S. tates of Louisiana and Washington observatories were constructed with “L” shaped tunnels, each a kilometer long. A laser beam could be shot and split in two along the tunnels, each individual beam traveling along the “L” until it reached a mirror at the end and returned to a collection pad recording the amount of time it took for the light to return. Since the beams were both traveling the same speed (the speed of light), it would take the exact same amount of time to return to the detector.
Over a billion years ago, or roughly 1.3 billion light years away, two black holes, both about 30 times more massive than our Sun, collided at about half the speed of light. As you can imagine, this caused a tremendous amount of energy to be released. At LIGO as the beams continued to race to the detector something incredible happened, at both facilities 1,000 miles apart, a “chirp” was detected, meaning the lasers returned to the pad at different times.
The only way this could happen would be that time and space had warped making one side of the “L” stretch farther away in spacetime and the other to scrunch closer, exactly how a ripple would behave on a pond. That massive collision sent out these ripples across the cosmos over 1.3 billion years until it hit our sensors and once again, rewrote our understanding of physics, proving Einstein right once again. Gravity is indeed just a bending of the fabric of space.
Why does this matter? Einstein’s theory of relativity is why we have accurate GPS, an invaluable asset to travel with infinite applications in both private and military markets. Now that we have witnessed a physical manifestation of the reality of his theory, doors are opened and we are just beginning to emerge into a realm of new fantastic possibilities. In fact this makes time travel a mere problem of engineering. Get to it.

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