Gravitational waves, Einstein’s ripples in spacetime, spotted for first time

By Adrian ChoFeb. 11, 2016 , 10:30 AM

Long ago, deep in space, two massive black holes—the ultrastrong gravitational fields left behind by gigantic stars that collapsed to infinitesimal points—slowly drew together. The stellar ghosts spiraled ever closer, until, about 1.3 billion years ago, they whirled about each other at half the speed of light and finally merged. The collision sent a shudder through the universe: ripples in the fabric of space and time called gravitational waves. Five months ago, they washed past Earth. And, for the first time, physicists detected the waves, fulfilling a 4-decade quest and opening new eyes on the heavens.
Gravitational waves, Einstein’s ripples in spacetime, spotted for first time

The discovery marks a triumph for the 1000 physicists with the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of gigantic instruments in Hanford, Washington, and Livingston, Louisiana. Rumors of the detection had circulated for months. Today, at a press conference in Washington, D.C., the LIGO team made it official. “We did it!” says David Reitze, a physicist and LIGO executive director at the California Institute of Technology (Caltech) in Pasadena. “All the rumors swirling around out there got most of it right.”

Albert Einstein predicted the existence of gravitational waves 100 years ago, but directly detecting them required mind-boggling technological prowess and a history of hunting. (See a timeline below of the history of the search for gravitational waves.) LIGO researchers sensed a wave that stretched space by one part in 1021, making the entire Earth expand and contract by 1/100,000 of a nanometer, about the width of an atomic nucleus. The observation tests Einstein’s theory of gravity, the general theory of relativity, with unprecedented rigor and provides proof positive that black holes exist. “It will win a Nobel Prize,” says Marc Kamionkowski, a theorist at Johns Hopkins University in Baltimore, Maryland.

LIGO watches for a minuscule stretching of space with what amounts to ultraprecise rulers: two L-shaped contraptions called interferometers with arms 4 kilometers long. Mirrors at the ends of each arm form a long “resonant cavity,” in which laser light of a precise wavelength bounces back and forth, resonating just as sound of a specific pitch rings in an organ pipe. Where the arms meet, the two beams can overlap. If they have traveled different distances along the arms, their waves will wind up out of step and interfere with each other. That will cause some of the light to warble out through an exit called a dark port in synchrony with undulations of the wave.

From the interference, researchers can compare the relative lengths of the two arms to within 1/10,000 the width of a proton—enough sensitivity to see a passing gravitational wave as it stretches the arms by different amounts. To spot such tiny displacements, however, scientists must damp out vibrations such as the rumble of seismic waves, the thrum of traffic, and the crashing of waves on distant coastlines.
Gravitational waves, Einstein’s ripples in spacetime, spotted for first time

V. Altounian/Science

On 14 September 2015, at 9:50:45 universal time—4:50 a.m. in Louisiana and 2:50 a.m. in Washington—LIGO’s automated systems detected just such a signal. The oscillation emerged at a frequency of 35 cycles per second, or Hertz, and sped up to 250 Hz before disappearing 0.25 seconds later. The increasing frequency, or chirp, jibes with two massive bodies spiraling into each other. The 0.007-second delay between the signals in Louisiana and Washington is the right timing for a light-speed wave zipping across both detectors.

The signal exceeds the “five-sigma” standard of statistical significance that physicists use to claim a discovery, LIGO researchers report in a paper scheduled to be published in Physical Review Letters to coincide with the press conference. It’s so strong it can be seen in the raw data, says Gabriela González, a physicist at Louisiana State University, Baton Rouge, and spokesperson for the LIGO scientific collaboration. “If you filter the data, the signal is obvious to the eye,” she says.

Comparison with computer simulations reveals that the wave came from two objects 29 and 36 times as massive as the sun spiraling to within 210 kilometers of each other before merging. Only a black hole—which is made of pure gravitational energy and gets its mass through Einstein’s famous equation E=mc2—can pack so much mass into so little space, says Bruce Allen, a LIGO member at the Max Planck Institute for Gravitational Physics in Hanover, Germany. The observation provides the first evidence for black holes that does not depend on watching hot gas or stars swirl around them at far greater distances. “Before, you could argue in principle whether or not black holes exist,” Allen says. “Now you can’t.”

The collision produced an astounding, invisible explosion. Modeling shows that the final black hole totals 62 solar masses—3 solar masses less than the sum of the initial black holes. The missing mass vanished in gravitational radiation—a conversion of mass to energy that makes an atomic bomb look like a spark. “For a tenth of a second [the collision] shines brighter than all of the stars in all the galaxies,” Allen says. “But only in gravitational waves.”
The LIGO facility in Livingston, Louisiana, has a twin in Hanford, Washington.

The LIGO facility in Livingston, Louisiana, has a twin in Hanford, Washington.

© ATMOSPHERE AERIAL

Other stellar explosions called gamma-ray bursts can also briefly outshine the stars, but the explosive black-hole merger sets a mind-bending record, says Kip Thorne, a gravitational theorist at Caltech who played a leading role in LIGO’s development. “It is by far the most powerful explosion humans have ever detected except for the big bang,” he says.

For 5 months, LIGO physicists struggled to keep a lid on their pupating discovery. Ordinarily, most team members would not have known whether the signal was real. LIGO regularly salts its data readings with secret false signals called “blind injections” to test the equipment and keep researchers on their toes. But on 14 September 2015, that blind injection system was not running. Physicists had only recently completed a 5-year, $205 million upgrade of the machines, and several systems—including the injection system—were still offline as the team wound up a preliminary “engineering run.” As a result, the whole collaboration knew that the observation was likely real. “I was convinced that day,” González says.

Still, LIGO physicists had to rule out every alternative, including the possibility that the reading was a malicious hoax. “We spent about a month looking at the ways that somebody could spoof a signal,” Reitze says, before deciding it was impossible. For González, making the checks “was a heavy responsibility,” she says. “This was the first detection of gravitational waves, so there was no room for a mistake.”

Proving that gravitational waves exist may not be LIGO’s most important legacy, as there has been compelling indirect evidence for them. In 1974, U.S. astronomers Russell Hulse and Joseph Taylor discovered a pair of radio-emitting neutron stars called pulsars orbiting each other. By timing the pulsars, Taylor and colleague Joel Weisberg demonstrated that they are very slowly spiraling toward each other—as they should if they’re radiating gravitational waves.

It is by far the most powerful explosion humans have ever detected except for the big bang.
Kip Thorne

It is the prospect of the science that might be done with gravitational waves that really excites physicists. For example, says Kamionkowski, the theorist at Johns Hopkins, the first LIGO result shows the power of such radiation to reveal unseen astrophysical objects like the two ill-fated black holes. “This opens a new window on this vast population of stellar remnants that we know are out there but of which we have seen only a tiny fraction,” he says.

The observation also paves the way for testing general relativity as never before, Kamionkowski says. Until now, physicists have studied gravity only in conditions where the force is relatively weak. By studying gravitational waves, they can now explore extreme conditions in which the energy in an object’s gravitational field accounts for most or all of its mass—the realm of strong gravity so far explored by theorists alone.
Rainer Weiss at the New York Science Fair.

Rainer Weiss at the New York Science Fair.

Matt Weber

With the black hole merger, general relativity has passed the first such test, says Rainer Weiss, a physicist at the Massachusetts Institute of Technology (MIT) in Cambridge, who came up with the original idea for LIGO. “The things you calculate from Einstein’s theory look exactly like the signal,” he says. “To me, that’s a miracle.”

The detection of gravitational waves marks the culmination of a decades-long quest that began in 1972, when Weiss wrote a paper outlining the basic design of LIGO. In 1979, the National Science Foundation funded research and development work at both MIT and Caltech, and LIGO construction began in 1994. The $272 million instruments started taking data in 2001, although it was not until the upgrade that physicists expected a signal.

If LIGO’s discovery merits a Nobel Prize, who should receive it? Scientists say Weiss is a shoo-in, but he demurs. “I don’t like to think of it,” he says. “If it wins a Nobel Prize, it shouldn’t be for the detection of gravitational waves. Hulse and Taylor did that.” Many researchers say other worthy recipients would include Ronald Drever, the first director of the project at Caltech who made key contributions to LIGO’s design, and Thorne, the Caltech theorist who championed the project. Thorne also objects. “The people who really deserve the credit are the experimenters who pulled this off, starting with Rai and Ron,” he says.

Meanwhile, other detections may come quickly. LIGO researchers are still analyzing data from their first observing run with their upgraded detectors, which ended 12 January, and they plan to start taking data again in July. A team in Italy hopes to turn on its rebuilt VIRGO detector—an interferometer with 3-kilometer arms—later this year. Physicists eagerly await the next wave.


See more of Science's coverage of gravitational waves.
From prediction to reality: a history of the search for gravitational waves
1915 Albert Einstein publishes general theory of relativity, explains gravity as the warping of spacetime by mass or energy
1916 Einstein predicts massive objects whirling in certain ways will cause spacetime ripples—gravitational waves
1936 Einstein has second thoughts and argues in a manuscript that the waves don't exist—until reviewer points out a mistake
1962 Russian physicists M. E. Gertsenshtein and V. I. Pustovoit publish paper sketch optical method for detecting gravitational waves—to no notice
1969 Physicist Joseph Weber claims gravitational wave detection using massive aluminum cylinders—replication efforts fail
1972 Rainer Weiss of the Massachusetts Institute of Technology (MIT) in Cambridge independently proposes optical method for detecting waves
1974 Astronomers discover pulsar orbiting a neutron star that appears to be slowing down due to gravitational radiation—work that later earns them a Nobel Prize
1979 National Science Foundation (NSF) funds California Institute of Technology in Pasadena and MIT to develop design for LIGO
1990 NSF agrees to fund $250 million LIGO experiment
1992 Sites in Washington and Louisiana selected for LIGO facilities; construction starts 2 years later
1995 Construction starts on GEO600 gravitational wave detector in Germany, which partners with LIGO and starts taking data in 2002
1996 Construction starts on VIRGO gravitational wave detector in Italy, which starts taking data in 2007
2002–2010 Runs of initial LIGO—no detection of gravitational waves
2007 LIGO and VIRGO teams agree to share data, forming a single global network of gravitational wave detectors
2010–2015 $205 million upgrade of LIGO detectors
2015 Advanced LIGO begins initial detection runs in September
2016 On 11 February, NSF and LIGO team announce successful detection of gravitational waves
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Space Gravitational waves

DOI: 10.1126/science.aaf4041
Adrian Cho
Adrian Cho

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Marco Drago saw the first gravitational wave on 14 September 2015.
Here’s the first person to spot those gravitational waves
The LIGO facility in Livingston, Louisiana.
‘Woohoo!’ email stokes rumor that gravitational waves have been spotted "


http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time/

not buying it just yet, but it probably is somewhat true

I've been watching this on the news today.

To think Einstein theorised this 100 years ago, amazing.

The way a scientist explained what it means here, is that right now they use light to look back in time, but with light they can only go so far back.
With these gravitational waves they will be able to go even further back in time, maybe even to the big bang itself or just after it.


Off topic slightly
Which makes me wonder, Einstein had an idea that maybe there was no big bang at all, but he couldn't get the physics at that time to add up, so he never pursued it.

Was he correct with this too, answers on a postcard please.

he stated that a couple of times, but then dropped that idea... i personally don't believe in the big bang, but thats just me...

I've wondered about that too, and how the universe came to be in existence, where did it all start, what was there before it started to exist. Gives me a headache thinking too much

i don't think that can be answered right now, with our currant information available, but i'm thinking it's trillions of years old, a big recycling pit... a star or a black hole blows up, and other stars and planets are formed from that... seems to be the best idea i can see

Quote
I've wondered about that too, and how the universe came to be in existence, where did it all start, what was there before it started to exist. Gives me a headache thinking too much


Joe,when problems of this magnitude strike,get an opinion from nailcap,guaranteed relief from all headaches.
To misquote Einstein "laughter is the best medicine".

Quote
I've wondered about that too, and how the universe came to be in existence, where did it all start, what was there before it started to exist. Gives me a headache thinking too much


Joe,when problems of this magnitude strike,get an opinion from nailcap,guaranteed relief from all headaches.
To misquote Einstein "laughter is the best medicine".

Joe,when problems of this magnitude strike,get an opinion from nailcap,guaranteed relief from all headaches.
To misquote Einstein "laughter is the best medicine".


When nailcap comments the theory of relativity becomes irrelevant.

Moe,

Many sites have picked this up now, there are a few articles on it now.
A live press conference was scheduled & I had 2 links to stream it. But both kept reading 'off line', so I didn't post them here.
I checked for YouTube recording of it. Nothing. Ugh... There was hype on this for 3 days. I am disappointed.

http://mashable.com/2016/02/11/einstein-gravitational-waves-detection/
--------------------
Einstein On Line

http://www.einstein-online.info/elementary/gravWav/
* I didn't see any announcement on this site*
-------------
Gravitational Waves Simply Explained With A Cube & Marble

http://youtu.be/pVQm9ijG3-4/
01:27
February 10, 2016
---------------
Gravitational wave simulations:

http://youtu.be/f9dhj3mP6F0/
00:14
February 8, 2016

Hhaa.. Postcard

No it has never been proven or disproving. IMO.
.But within the last few hours it seems to be the talk that if Einstein was right about this ' Magnetic Ripples', then he may also be correct about the Big Bang.

Steven Hawkins.. Well he back to being an atheist. He wasn't for about a week ..

Personally I don't believe in The Big Bang.
Even if it is true. Well...why?
God did it..because he wanted to.
Hhhaaa

Astronomy

Scientists find evidence of gravitational waves predicted by Einstein

By Michael Casey
Published February 11, 2016

Scientists detect gravitational waves predicted by Einstein

After decades of searching, scientists announced Thursday that they have detected gravitational waves -- essentially ripples in the fabric of space-time -- that had been predicted by Einstein.

An international team of astrophysicists said that they detected the waves from the distant crash of two black holes, using a $1.1 billion instrument. The Ligo Collaboration was behind the discovery and it has been accepted for publication in the journal Physical Review Letters.

"We have detected gravitational waves," Caltech’s David H. Reitze, executive director of the LIGO Laboratory, told journalists at a news conference in Washington, DC.

A technician works on one of LIGO's optics. At each observatory, the 2 1/2-mile long L-shaped LIGO interferometer uses laser light split into two beams that travel back and forth down the arms. The beams are used to monitor the distance between mirrors precisely positioned at the ends of the arms. According to Einstein's theory, the distance between the mirrors will change when a gravitational wave passed by the detector.

A technician works on one of LIGO's optics. At each observatory, the 2 1/2-mile long L-shaped LIGO interferometer uses laser light split into two beams that travel back and forth down the arms. The beams are used to monitor the distance between mirrors precisely positioned at the ends of the arms. According to Einstein's theory, the distance between the mirrors will change when a gravitational wave passed by the detector. (LIGO Laboratory)

“Our observation of gravitational waves accomplishes an ambitious goal set out over five decades ago to directly detect this elusive phenomenon and better understand the universe, and, fittingly, fulfills Einstein’s legacy on the 100th anniversary of his general theory of relativity,” Reitze said in a statement.

The news, according to the Associated Press, is being compared by at least one theorist to Galileo taking up a telescope and looking at the planets and the biggest discovery since the discovery of the Higgs particle. It has stunned the world of physics and astronomy, prompting scientists to say it is the beginning of a new era in physics that could lead to scores more astrophysical discoveries and the exploration of the
warped side of the universe.

“Every year I tell my Gravity class about the three classics successes of General Relativity: the perihelion precession of Mercury, light bending and gravitational redshift. Next year, I’ll be adding a fourth: gravitational waves,” Tony Padilla, Royal
Society University Research Fellow in the School of Physics & Astronomy at the University of Nottingham, said in a statement.

“Their detection is a stunning triumph for experiment, for theory, and most notably, for Einstein. And the source of these waves is rumored to be a merger of two black holes. Wow! Just wow! Black holes really exist," he said. "No more arguments. Looking further ahead we can look forward to a whole new era for astronomy, listening out for these remarkable signals that will teach us so much about the fundamental nature of gravity and the Universe. It’s almost as if we have grown a new set of ears, and there could be so much to hear!”

An aerial view of the Laser Interferometer Gravitational-wave Observatory (LIGO) detector in Livingston, Louisiana. LIGO has two detectors: one in Livingston and the other in Hanaford, Washington. LIGO is funded by NSF; Caltech and MIT conceived, built and operate the laboratories.

An aerial view of the Laser Interferometer Gravitational-wave Observatory (LIGO) detector in Livingston, Louisiana. LIGO has two detectors: one in Livingston and the other in Hanaford, Washington. LIGO is funded by NSF; Caltech and MIT conceived, built and operate the laboratories. (LIGO Laboratory)

The discovery confirms a major prediction of Albert Einstein’s 1915 general theory of relativity. Gravitation waves carry information about their dramatic origins and about the nature of gravity that cannot be obtained from elsewhere.

Not only have they fascinated scientists, but found their way into pop culture -- namely through movies such as "Back to the Future," where the space-time continuum was used as a medium for the DeLorean time machine to go back in time. It also was featured in the "Terminator" series.

Related: Einstein's personal letters auctioned for more than $420,000

Their existence was first demonstrated in the 1970s and 1980s by Joseph Taylor, Jr., and colleagues. In 1974, Taylor and Russell Hulse discovered a binary system composed of a pulsar in orbit around a neutron star. Taylor and Joel M. Weisberg in 1982 found that the orbit of the pulsar was slowly shrinking over time because of the release of energy in the form of gravitational waves. For discovering the pulsar and showing that it would make possible this particular gravitational wave measurement, Hulse and Taylor were awarded the 1993 Nobel Prize in Physics.

In the latest breakthrough, the gravitational waves were detected on Sept. 14, 2015, by both of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, La., and Hanford, Wash.

Based on the observed signals, LIGO scientists estimate that the black holes for this event were about 29 and 36 times the mass of the sun, and the event took place 1.3 billion years ago. About three times the mass of the Sun was converted into gravitational waves in a fraction of a second -- with a peak power output about 50 times that of the whole visible universe.

By looking at the time of arrival of the signals -- the detector in Livingston recorded the event 7 milliseconds before the detector in Hanford -- scientists can say that the source was located in the Southern Hemisphere.

According to general relativity, a pair of black holes orbiting around each other lose energy through the emission of gravitational waves, causing them to gradually approach each other over billions of years, and then much more quickly in the final minutes. In a final fraction of a second, the two black holes collide and form one massive black hole. A portion of their combined mass is converted to energy, according to Einstein’s formula E=mc2, and this energy is emitted as a final strong burst of gravitational waves.


“With this discovery, we humans are embarking on a marvelous new quest: the quest to explore the warped side of the universe -- objects and phenomena that are made from warped spacetime. Colliding black holes and gravitational waves are our first beautiful examples,” Caltech's Kip Thorne said.

Others, like David Clements, an astrophysicist at Imperial College London, said the discovery gives the world "a whole new tool with which to look at the universe, allowing us to look at some of the most energetic events imaginable -- collisions of black holes and neutron stars -- in ways that just were not possible before. We now have a whole new spectrum of radiation with which to study the universe.

“It’s as if we were blind and today LIGO has opened our eyes,” he said in a statement.

http://www.foxnews.com/science/2016/02/11/scientists-find-evidence-gravitational-waves-predicted-by-einstein.html?cmpid=NL_SciTech/
* Pics, video & embedded links *

We were not blind when LIGO was built. It's just another tool to prove what we had previously proven in many different ways, i.e., Einstein was right. General Relativity has been proven in a completely different way.

LIGO does allow us to "SEE" in gravitational waves instead of just light. The waves don't come along very often in a form strong enough to measure.(our equipment eventually will get much better). Soon, we will be able to detect gravitational waves several times a year instead of one event every several years. As detection sensitivity increases, the distance we can detect something increases dramatically.

kind of related, they are saying this will help them find the "great attractor"

http://www.mnn.com/earth-matters/space/stories/hidden-galaxies-emerge-milky-ways-dust

Was Einstein from the future.

i think his brain was...

i think his brain was...

Now you've got me thinking again

Which begs the question, would we, even today, had any idea that gravitational waves exist without his mind.

depends on what they actually are... like a black hole, they know something is there, but not sure what it actually is yet... they don't even know what gravity is, just it's effects... the tests they are doing is designed to prove his theory, so it could be biased as far as we know...

As far as I understand it he gave Newtons theory a whole new calculation, if that's the correct term to use, wasn't Einstein the first to write about black holes as well, I think he was although I may be wrong. What you said earlier, the great attractor.