ENDLESS FRONTIER:
INNOVATIONS IN SCIENCE & ENGINEERING

February 2016

100 Years After Einstein's Prediction, Gravitational Wave Detection Marks Start of New Era in Astronomy

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On Friday, February 12, news outlets throughout the country featured the story that scientists from MIT, Caltech and partners had definitively detected gravitational waves. "Albert Einstein and his 1,000 contemporary co-conspirators usurped [the prime news position] away from the presidential candidates and various Mideast wars," one reader remarked. [See "Commentary" below]. This special issue of The Endless Frontier collects some of the finest general news coverage of the gravitational wave observation by the LIGO collaborative, along with opinion pieces and links to the first research publication.

As these videos and articles report, the LIGO scientists and engineers did more than fulfill a 40-year quest to verify Einstein's 1916 prediction with exquisitely sensitive measurements, using "ordinary" tools like lasers, mirrors, and pendulums with unprecedented precision. Through detailed analysis, LIGO scientists showed that the waves emanated from something never before seen-the merging of two black holes over a billion years ago. Careful comparison with gravitational models reveals the masses of these objects before and after the merger, their distance, and the amount of mass converted to energy and radiated away as gravitational wave. These represent the first scientific results from a new kind of astronomy that officially began with twin detections by LIGO's interferometers in Hanford, WA and Livingston, LA at 09:50:45 UTC on September 14, 2015.

With Faint Chirp, Scientists Prove Einstein Correct

The New York Times

The discovery is a great triumph for three physicists - Kip Thorne of the California Institute of Technology, Rainer Weiss of the Massachusetts Institute of Technology and Ronald Drever, formerly of Caltech and now retired in Scotland - who bet their careers on the dream of measuring the most ineffable of Einstein's notions.

Cosmic Breakthrough: Physicists Detect Gravitational Waves From Violent Black-Hole Merger

The Washington Post - February 11, 2016

"Ladies and gentlemen, we have detected gravitational waves. We did it!" declared David Reitze, executive director of the Laser Interferometer Gravitational-Wave Observatory, drawing applause from an audience that included many luminaries of the physics world.

Gravitational Waves Detected 100 Years After Einstein's Prediction

MIT News Office - February 11, 2016

For the first time, scientists have observed ripples in the fabric of spacetime called gravitational waves, arriving at the Earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein's 1915 general theory of relativity and opens an unprecedented new window onto the cosmos. From the MIT press release.

Q&A: Rainer Weiss on LIGO's Origins

February 11, 2016

Today, LIGO involves some 950 scientists at universities around the United States, including MIT, and in 15 other countries. But nearly four decades ago, the instrument was merely an MIT class exercise, conceived by Rainer Weiss, now a professor emeritus of physics. MIT News spoke with Weiss about the history of LIGO's design and the 40-year effort to prove Einstein right.

Gravitational Waves Exist: The Inside Story of How Scientists Finally Found Them

The New Yorker - February 11, 2016

[Weiss'] first insight was to make the observatory "L"-shaped... As the wave expands space-time in one direction, it necessarily compresses it in the other. Weiss's instrument would gauge the difference between these two fluctuating lengths, and it would do so on a gigantic scale, using miles of steel tubing. "I wasn't going to be detecting anything on my tabletop," he said... Weiss wrote up his design in the spring of 1972, as part of his laboratory's quarterly progress report. The article never appeared in a scientific journal-it was an idea, not an experiment-but according to Kip Thorne, ... "it is one of the greatest papers ever written."  

 Gravitational Waves: Numbers Don't Do Them Justice

BBC News Online - February 11, 2016

It's astonishing; it really is." Jim Hough can't stop repeating the phrase...Imagine two monster black holes spinning down on each other in space. One has a mass which is about 35 times that of our Sun, the other roughly 30. At the moment just before they coalesce, they're turning around each other several tens of times a second. And then, their event horizons merge and they become one - like two soap bubbles in a bath.

What Gravitational Waves Sound Like

The Atlantic - February 11, 2016

Scientists have been trying to figure out how to "listen" to gravitational waves-and to prove their existence-ever since Einstein predicted them in 1915... In the words of Scott Hughes, "Gravity is a weak force. Measuring these things is bloody hard." Hughes is a theoretical physicist at MIT who has been contemplating LIGO since its inception in 1992. He has struggled with a question at the heart of the observatory program: Once we do hear gravitational waves, how will we know where they come from?

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Commentary

The Dividends of Investing in Science

An op-ed by MIT president Rafael Reif about the significance of the LIGO announcement was published in The Boston Globe on February 12, 2016.

Expanding Einstein's Vision: The Discovery of Gravitational Waves Shows Why Funding for Basic Research is So Vital

An op-ed by National Science Foundation director Dr. France Córdova, appeared in U.S. News & World Report on February 16, 2016. It can be found here.

The following letter to the editor appeared in the New York Times on February 12, 2016:

It gave me great pleasure to read Friday's lead article, "With Faint Chirp, Scientists Prove Einstein Correct," in which Albert Einstein and his 1,000 contemporary co-conspirators usurped that coveted position away from the presidential candidates and various Mideast wars. At least for one day our pitiable earthly problems had to yield to the monumental collisions of higher powers. God bless Einstein, the world of science and your wonderful science writer, Dennis Overbye, for placing our local woes in their proper perspective. - Benjamin Bederson, emeritus professor of physics, New York University.

Research Publications and Data

Observation of Gravitational Waves from a Binary Black Hole Merger. B.P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration). First appeared online in Physical Review Letters on February 11th, 2016.An accompanying Viewpoint appeared simultaneously in Physics, an online-only news and commentary journal from the same publisher. Both articles are freely available to all readers.

The LIGO Scientific Collaboration has released publicly released the data from the September 14th observations. The site also features additional information on the LIGO instruments, data analyses, and theoretical modeling.

LIGO Technology Advances

LIGO's technical teams have advanced the state of the art in several commercially important technology areas, including stable high-power infrared lasers, low-hydrogen steels for vacuum vessels, seismic vibration isolation platforms, high-gain control systems, and optical materials and surfaces. Descriptions can be found at  https://www.ligo.caltech.edu/mit/page/look-deeper.

Specific examples of technology developed for LIGO and now available for other uses include: Adaptive Beam Shaping, Pound-Drever-Hall Locking, Oxide Bonding Techniques , Blind Data Search Method, High Power Modulator, Slab Laser

Videos

Video interviews of MIT participants in the LIGO discovery can be found at YouTube.

Video coverage of the press conference announcing the LIGO results is also available.

For Further Information

Additional LIGO coverage can be accessed on the MIT News site.