By Maddie Stone / GIZMODO: This morning, the Internet erupted with rumors that physicists have finally observed gravitational waves; ripples in the fabric of spacetime predicted by Albert Einstein a century ago. While it isn’t the first time we’ve heard excited whispers about the elusive phenomena, the gossip feels more promising in light of the recently upgraded detector at the Laser Interferometer Gravitational Wave Observatory (LIGO) that’s behind all the hubbub.
Discovering gravitational waves would be a huge deal for physics, cosmology, and our understanding of the universe at large. But if you’re not a scientist studying one of the aforementioned fields, it’s possible you’ve never heard of these mysterious ripples. What the heck are gravitational waves, and why have physicists been struggling to find them for a century? Moreover, why should we care?
Simply put, gravitational waves are vibrations in the fabric of the universe—light-speed ripples in spacetime itself, caused by such epically violent events as exploding stars and black hole mergers. Thanks to inconceivably large, violent, and distant celestial happenings, the atoms that make up everything from the stars in the sky to the human beings on Earth are shaking a tiny bit, all the time.
And by tiny I really mean tiny. For all the energy that goes into producing gravitational waves, spacetime ripples themselves are incredibly faint. Physicists estimate that by the time gravitational waves reach Earth, they’re on the order of a billionth the diameter of an atom. You need ridiculously precise instruments operating in completely noise-free environments to measure them, and until very recently, our detectors simply haven’t been up to snuff.
But the gravitational wave detection game’s been changing of late, with a recent spate of improvements to our leading ground-based observatory, LIGO, and with the launch of the very first space-based gravitational wave detector, LISA Pathfinder. Armed with these two science laboratories, physicists are hopeful that we’ll be able to measure our very first spacetime ripples by the end of the decade. Now, it’s looking like that day might come a lot sooner.
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Image: Numerical simulation of two merging black holes performed by the Albert Einstein Institute in Germany. Image Credit: Werner Benger / Wikimedia