'Ringing' Black Hole Signal Confirms Both Einstein's and Hawking's Theories

Gravitational wave detections have provided yet another insight for fundamental physics, with a new detection that helps to bolster the work of both Albert Einstein and Stephen Hawking.
Scientists studied a series of gravitational wave signals with advanced analytical techniques designed to pull faint background wave signals out of a cacophony of larger waves. This wasn’t possible before, and in this case, an upgraded analytical technique rather than an upgraded piece of detection hardware provided the new insight.
The newly faint readings show the “ringing” waves produced at the very end of the merger of two black holes. Most of the waves produced come from their rapid orbit as they spiral toward one another, but fainter gravitational waves are also produced in the milliseconds after they collide as the two masses redistribute into a new, larger one.
Astronomers were able to view this characteristic ringing through the noise of the larger waves, and their observations revealed two things.
One: Black holes are the simple objects that Einstein predicted them to be. Two: Hawking was right about black holes and entropy.
The first is easier to describe. Einstein’s theories predict that black holes should be “fundamentally simple” objects that can be described mathematically by nothing more than their mass and their spin. These readings, looking at the two “before” black holes and the single “after” black hole, observationally confirm this prediction for the very first time.
The second is a bit more nuanced. According to Hawking’s area theorem, a black hole’s area should only be able to increase due to classical processes—the collision of two black holes being a perfect example. The ringing signal showed that this prediction held true for this particular collision.
This theorem is essentially broken by the existence of Hawking radiation, mind you, which is a quantum process that applies (or seems to apply, at least) outside the confines of relativistic physics.
The newly detectable ringing signal is just the first to be pulled from the mass of gravitational wave data currently coming out of LIGO. The researchers say they’re now getting a suitable detection every three days or so.
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