Gravitational Waves Discovery Confirms Einstein's Theory

Einstein was right: gravitational waves do exist. Scientists confirmed Einstein’s theory with the groundbreaking discovery, announced today at the National Press Club, that gravitational waves were detected after a collision of a pair of unusual black holes.

Michael Turner, a professor of astronomy and astrophysics and director of the Kavli Institute for Cosmological Physics at the University of Chicago, speaks with Here & Now’s Jeremy Hobson about what this discovery tells us about our understanding of the universe.

• Read more via LIGO (Laser Interferometer Gravitational-Wave Observatory)

Interview Highlights: Michael Turner

What exactly did scientists discover here?

“I would call this a Galileo moment. The big news today is that 1.3 billion years ago, in a galaxy far, far away, two black holes collided and coalesced to form one black hole, and they twisted and bent and roiled and contorted space-time and that started a ripple, a really big ripple. You would not have wanted to be in that ripple. That ripple traveled 1.3 billion light years to us and it was detected by the gravitational wave detectors in Livingston, Louisiana and in Hanford, Washington that were built by the NSF back in 1992.”

On the detection centers in Louisiana and Washington

“This ripple in space-time causes the distance between the end points of the gravitational wave detector, which are four kilometers apart, to change by less than a thousandth the size of the proton.”

Which means?

“10^-16 centimeters, if you really want it. But it's amazing that human beings can build instruments to do that, and in this new way we look at the universe, the brightest things, and the things that are the easiest to see, are really exotic things.”

Give us a sense of what this means for our understanding of the universe. How do we feel today versus yesterday about what's around us?

“I think number one is, Einstein's theory passed the last major test. That's a big one. These are black holes. In general relativity these are the simplest objects; they have the strongest fields and, I'm going to use a slightly technical term here, the waveform that was detected. When you plot the results, they look and see if the waveform agrees with what Einstein's theory says for two black holes coming together, and it does. So this is a big boost to our understanding of black holes, and then of course I think the final really big one that's so amazing is that advanced LIGO, they will have earned their ‘O.’ So Laser Interferometer Gravitational-Wave Observatory, so they're going to be seeing tens of events per year.”

So now that we can observe these waves, we can learn much more about them?

“That's right. So the rest of the year there are going to be 10 more events, some of them will be black holes coalescing, some of them will be a black hole leading a neutron star, and the ones that every scientist is so excited about are the surprises, where you go ‘Oh my god, what is that? We never calculated that. What's that thing?' So it's the surprises and every time we've turned our eyes on the universe with a new kind of instrument, x-rays or microwaves, the most important discovery is not the one we said, ‘Oh yeah, we're gonna do this one for sure,' it's the big surprise. People are very excited for what surprises lie ahead.”

Is this the most exciting moment of your scientific career?

“I've been very lucky. Dark matter, dark energy, inflation, this has just been a very exciting time in our understanding of the universe. I have to tell you about a meeting that took place, I spoke at it, in 1965. Before 1965 you could have said, ‘Oh, we live in a pretty boring universe. We've got these ordinary starts and this and that.' 1965 is kind of when this revolution began, the discovery of the microwave background that told us about the Big Bang. The discovery of quasars, which turned out to be objects powered by black holes followed by neutron stars. We live in this amazing universe in which stars like our sun are very ordinary and we have all these exotic objects that we're studying and inspiring the next generation of scientists with.”

Guest

• Michael Turner, director of the Kavli Institute for Cosmological Physics at the University of Chicago.

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