Mistakes have been made before, and it’s possible that this discovery will be challenged like last time, but scientists at LIGO have announced that they’re certain they’ve detected gravitational waves for the first time.
First, let’s take a look at why this is so important and exciting, which starts with the question, “What are gravitational waves?” Gravitational waves are ripples in the very fabric of the Universe itself. You probably know that gravity is theoretically caused by the mass of objects in space causing that space to warp and attract objects together. So, when there’s a violent event involving massive bodies in space—say, two black holes merging, as was the case with the Laser Interferometer Gravitational-Wave Observatory’s (LIGO) experiment—ripples of warped space radiate outward throughout the Universe and cause atoms to vibrate an an infinitesimal scale.
These “waves” are a cornerstone of Einstein’s Theory of General Relativity, and proving their existence is not only a validation of one of the foundations of our understanding of the Universe, but also another useful tool in helping us learn even more about it. Waves created by the Big Bang were believed to have been detected recently, but that “discovery” was eventually shot down.
Of course, that’s because detecting this waves is about as hard as it sounds. When spacetime itself expands and contracts, especially at minuscule levels detected at a safe distance from the kind of cataclysmic event we’d expect to cause the waves, we don’t really notice it happening. LIGO’s experiments involve shooting lasers (pew pew) between mirrors in vacuum tubes 4 kilometers in length, situated almost 2,000 miles apart in Washington State and Louisiana. That way, they can be certain that the tiny fluctuations they detect in the distance between the tubes’ mirrors aren’t caused by local vibrations.
It sounds extreme, but it seems to have paid off. Rumors have been floating around for a while that LIGO was getting ready to announce the waves’ discovery, but they wanted to take their time, analyze the data, and be absolutely certain of their achievement before announcing it to the world. Now, they’ve made their announcement, and their work has been accepted for publication in the journal Physical Review Letters.
So what now? Well, there’s plenty of information to be mined from these waves as we get better at detecting them. The ones LIGO found so far come from a collision of two black holes of about 29 and 36 times the mass of our Sun, and they ran into each other about 1.3 billion years ago. Light—which we’re used to seeing with—isn’t always helpful in investigating these celestial phenomena, so the gravitational waves they create may help us learn more about them.
MIT astrophysicist Scott Hughes told Gizmodo,
There’s a lot of rich information encoded in gravitational waves. As an astronomer, I try to think about how to go from the “sound” of the waveform that LIGO measures, to the parameters that produce that waveform. Actually getting some demographic data is one of the key things we hope to do in an era of detection. Whenever first detection happens, there’s gonna be a party, no question, but after that, when detection becomes routine, is when things start getting really interesting.
As exciting as the discovery and Einstein’s validation is, it’s really just the beginning of even more exciting new understanding of the Universe, and that’s the great thing about science.
(image via Taro Taylor on Flickr)
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