Today will go down in the history books as the day we directly detected gravitational waves. The discovery, made by scientists of the LIGO Science Collaboration, is a Nobel Prize-worthy event that equals, and maybe even surpasses, the discovery of the Higgs boson in 2012 and the realization by Edwin Hubble in 1929 that the universe is expanding.
NEWS: Gravitational Waves Detected for First Time
"We can now hear the universe," said LIGO physicist and spokesperson Gabriela Gonzalez during Thursday's National Science Foundation's historic meeting in Washington D.C. "The detection is the beginning of a new era: The field of gravitational astronomy is now a reality."
Although gravitational waves were first theorized by Einstein's theory of general relativity a century ago, it's only now that humanity has the technology to physically measure these ripples in spacetime. Using LIGO, which stands for Laser Interferometer Gravitational-Wave Observatory, exquisitely tiny fluctuations in spacetime can be measured and, shortly after its sensitivity upgrade in September last year, the universe gave LIGO a gravitational gift.
VIDEO: Gravitational Waves Confirmed: A Historic Discovery
Gravitational waves are generated when massive objects accelerate, collide or explode. If we can measure the gravitational wave signature of these events, we can learn a lot about their properties and even use them in a new era of gravitational wave astronomy.
It would be a paradigm shift away from "regular" astronomy that studies cosmic radiation from the electromagnetic spectrum; the gravitational wave spectrum can reveal the "dark" universe, where black holes collide and neutron stars quietly orbit one another in the night.
And on Sept. 14, 2015, one of the biggest eruptions of gravitational waves thought possible to occur in the universe was detected by LIGO's freshly upgraded laser system.
EXPLAINER: What You Need to Know About Gravitational Waves
Approximately 1.3 billion light-years away, two black holes became trapped in their mutual gravitational well and started to rapidly orbit one another. Binary black holes are thought to be an inevitable part of the cosmic landscape, but this is the first time that we have directly detected two black holes - 29 and 36 times the mass of our sun - just before merging. Watch a computer visualization of merging black holes: