A team of physicists announced today that they have been able to detect and hear the sound of a gravitational wave. There it is. The sound is generated by a ripple in space time, a phenomenon predicted by Albert Einstein 100 years ago. The researchers say gives astronomers a whole new way to study the universe with years as well as eyes. Earlier today I spoke with George Fuller, professor of Center for Astrophysics and Space Sciences. Hears that interview. Professor Fuller, researchers say this is a gravitational wave created by a tremendous force. Where did it come from? What they are telling us in presented in the press conference this morning, is that it came from the merger, the collision of two black holes. These are black holes that orbit around one another. And the masses of the black holes are rather large. Each of them are about 30 times the mass of the sun to. And as they orbit around one another, they emit these gravitational waves as they do that, they lose energy in their or Bert and the spiral into one another and qualified. And this -- collide. In this collision happened to billion years ago? Yes. According to the press conference this morning, they contacted at roughly 1 point they contacted at roughly 1.2 billion years ago. What do gravitational waves due to the fabric of space time? They are like ripples. So they dredge and compress. They compress and stretch instances, in time. So think of dropping a rock or pebble into a pond and watch the ripples in the water in the surface of the water. They cannot from where the rock or pebble went into the water. It is much like that. Of these are propagating ripples in the fabric of the space and time itself. So it is one of these things propagates by, if you are standing there, you won't feel this, because these are extremely weak, but what would happen is as one of these ripples were to pass by, you would be compressed and stretched and alternately stretched and compressed. So as you are saying, what this does is it actually changes the space time? Yes it does. With time. Professor Fuller, is this confirmation of Einstein's theory? Or were scientists convinced of gravitational waves before this? You are convinced about gravitational waves for a number of reasons. However, this is the first direct detection of a gravitational wave. All of our inferences about gravitational waves before this word from in directed inferences -- indirect inferences. What I have read in my crash course this morning is that before gravitational waves are so hard to determine because most times they are pretty placid. They are sort of like watching a lake with no ripples on it. But you need a cataclysmic event like though collision of the two black holes in order to be able to detect that anything is actually out there. Is that right? Yes. There is a lot of energy in the source that generated the gravitational waves in this particular case. So if you took the mass of the sun, multiply that by three, and then annihilated all of that mass in three times the mass of the sun, into gravitational radiation, that's what happened in this binary black hole merger. So a tremendous amount of energy. But it was a long way away. It was a very long way away. Give us an idea if you would about why this is such a significant discovery. My answer to that is probably a little different then you may have heard other places, but it was something that chip Thoren said in the conference. This opens a whole new way of looking, a whole new window on the universe, a whole new way of looking at the cosmos. Traditionally what we have seen is whenever we open up a new way of looking at things, we learn all kinds of things. In many cases we learn very unexpected things. That is the real significance of this is that this is a real gravitational wave astronomy. We can study the cosmos in this whole new way, this whole new modality. So this assist, the one you've just talked about, he's been one of the most recent scientists to push this. Homeowners have scientist been looking? I would say Born is in many ways the father of the field of gravitational ways of astronomy and even astrophysics. I think the quest for detecting gravitational waves from the early 60s. And he was a young theorist at that time working with John Wheeler and other people around the world in trying to develop a theoretical idea about how stars collapse and the physics of black holes. But by the 1970s he had really pushed to try to actually build and figure out how to build gravitational wave detectors along the lines of what we see now with my go. -- LIGO I wish you could tell us a little more about this project. This is where it was detected I believe last September. It uses lasers to try to measure the waves, is that right That is correct. What it is, in essence, it's what we call in interferometer. Or Michelson interferometer. It has a mirror at either end of 24 km long -- to 4 km long bars that reach each other, and a laser signal is bouncing back and forth between the mirrors in the interferometer. And the interferometer is arranged in a way that no energy comes out if the length of these arms is fixed. So as a gravitational wave comes by, it moves, it alternately compresses and stretches this laser interferometer arm and that destroys the interference and allows energy to leak out into a detector. That is how it works. Now you asked me earlier about the kind of energy or magnitude of these waves. To give you some perspective on this, and I think it was said in the press conference, this is the most precise measuring instrument ever built. The arm of that interferometer is for kilometers in length. So in that, the gravitational wave as it comes by will stretch that by something of order of thousand the size of -- 1000 the size of a proton. Will other test be needed to confirm the results? No. Because of the accuracy of the device? I think this particular event they captured were these two were these 230 some solar mass black objects moved, the amplification of the waves was prodigious by gravitational wave standards. And the signal in the detector was unambiguous. I see. There are probably other evens they are not talking about yet. I ensure that collaboration has very high standards for going public with this. But there are probably other things or events that are more numerous that I would guess that are probably not so easy to pull out of the background noise. Professor Fuller, can you explain to us a bit more what it means to give astronomers years as well as eyes to explore the universe? Might be listen for? Well the years in this case are these interferometers for gravitational waves. Gravitational waves are not like soundwaves or even light length for radio. They are very different. This will allow -- that would generate the waves are large amounts of mass and energy moving and accelerating quickly. That is what generate these waves. What we are going to be able to do now is look into violent and him and on that involve these exotic phenomenon like merging black holes or merging neutron stars, colliding neutron stars. We can't really see these things. They would put out electromagnetic energy, but it would be harder to measure that. There might not be any from in some cases, from some black holes. From merging neutron stars there might be stars -- some. It might be interesting to explore this new venue and maybe other things they admit as well such as gamma rays and electromagnetic radiation. Is it possible that we might detect traces of the big bang? Well, I think at the press conference, for example, one possibility that has been talked about by the community is other sources of high mass or high energy density moving and accelerating quickly. One example is cosmic strings. That is a possibility. Those could admit radiation gravitation. And they were in the very early universe. How does this affect your work at UC San Diego? Well many of us at UC San Diego are working one way or another on the kind of phenomenon that can be detected with LIGO. A lot of my work deals with the compact of stars, like merging neutron stars, especially the neutrinos that are produced, there are people who work directly on the simulation that were mentioned today earlier in the press conference. Of that would be Michael Holtz, who is an expert in relativity and his joint physics and mathematics here. Lee Lindblom who is a research faculty member in [ Indiscernible Name ] and another of others as well who work on the physics of these events. And moreover, there are astronomers here associated with the task or principally interested in how black holes grow in size. We know that galaxies, almost every galaxy has a super black hole at the center. And a great mystery in physics is figuring out how we get those things. How are they formed? Something like my go -- LIGO, will have an observational handle on that. Thank you. George Fuller from UC San Diego's Center for astrophysics and space thank you so much. Thank you. [ Music ] . Coming up how long will sinuous heatwave last? And a report on infection risks a California hospitals. It's 12:26 PM. You're listening to KPBS Midday edition. [ Music ]
In an announcement that electrified the world of astronomy, scientists said Thursday that they have finally detected gravitational waves, the ripples in the fabric of space-time that Einstein predicted a century ago.
Astronomers hailed the finding as achievement of historic proportions, one that opens the door to a new way of observing the cosmos and the violent collisions that are constantly shaping it. For them, it's like turning a silent movie into a talkie because these waves are the soundtrack of the universe.
"Until this moment, we had our eyes on the sky and we couldn't hear the music," said Columbia University astrophysicist Szabolcs Marka, a member of the discovery team. "The skies will never be the same."
An all-star international team of astrophysicists used a newly upgraded and excruciatingly sensitive $1.1 billion set of twin instruments known as the Laser Interferometer Gravitational-wave Observatory, or LIGO, to detect a gravitational wave generated by the collision of two black holes 1.3 billion light-years from Earth.
To make sense of the raw data, the scientists converted the wave into sound. At a news conference, they played a recording of what they called a "chirp" — the signal they heard on Sept. 14. It was barely perceptible even when enhanced.
Some physicists said the finding is as big a deal as the 2012 discovery of the subatomic Higgs boson, sometimes called the "God particle." Some said this is bigger.
"It's really comparable only to Galileo taking up the telescope and looking at the planets," said Penn State physics theorist Abhay Ashtekar, who wasn't part of the discovery team. "Our understanding of the heavens changed dramatically."
Gravitational waves, first theorized by Albert Einstein in 1916 as part of his theory of general relativity, are extraordinarily faint ripples in space-time, the hard-to-fathom fourth dimension that combines time with the familiar up, down, left and right. When massive objects like black holes or neutron stars collide, they send gravitational waves across the universe, stretching space-time or causing it to bunch up like a fishing net.
Scientists found indirect proof of the existence of gravitational waves in the 1970s — computations that showed they ever so slightly changed the orbits of two colliding stars — and the work was honored as part of the 1993 Nobel Prize in physics. But Thursday's announcement was a direct detection of a gravitational wave.
And that's considered a big difference.
"It's one thing to know soundwaves exist, but it's another to actually hear Beethoven's Fifth Symphony," said Marc Kamionkowsi, a physicist at Johns Hopkins University who wasn't part of the discovery team. "In this case we're actually getting to hear black holes merging."
Gravitational waves are the "soundtrack of the universe," said team member Chad Hanna of Pennsylvania State University.
Detecting gravitational waves is so difficult that when Einstein first theorized about them, he figured scientists would never be able to hear them. The greatest scientific mind of the 20th century later doubted himself and questioned in the 1930s whether they really do exist, but by the 1960s scientists had concluded they probably do, Ashtekar said.
In 1979, the National Science Foundation decided to give money to the California Institute of Technology and the Massachusetts Institute of Technology to come up with a way to detect the waves.
Twenty years later, they started building two LIGO detectors in Hanford, Washington, and Livingston, Louisiana, and they were turned on in 2001. But after years with no luck, scientists realized they had to build a more advanced system, which was turned on last September.
"This is truly a scientific moonshot and we did it. We landed on the moon," said David Reitze, LIGO's executive director.
The new LIGO in some frequencies is three times more sensitive than the old one and is able to detect ripples at lower frequencies that the old one couldn't. And more upgrades are planned.
Sensitivity is crucial because the stretching and squeezing of space-time by these gravitational waves is incredibly tiny. Essentially, LIGO detects waves that stretch and squeeze the entire Milky Way galaxy "by the width of your thumb," Hanna said.
Each LIGO has two giant perpendicular arms more than 2 miles long. A laser beam is split and travels both arms, bouncing off mirrors to return to the arms' intersection. Gravitational waves stretch the arms to create an incredibly tiny mismatch — smaller than a subatomic particle — in the beams' locations. That mismatch is what LIGO detects.
"We are fairly certain that we will find more and more signals," Marka said. "This is just a start."
