An idea coming to mind long time ago
"The first direct observation of gravitational waves by LIGO is an extraordinary demonstration of scientific vision and persistence. Through four decades of development of exquisitely sensitive instrumentation - pushing the capacity of our imaginations — we are now able to glimpse cosmic processes that were previously undetectable. It is truly the start of a new era in astrophysics," as Caltech president and professor of physics Thomas F. Rosenbaum had put it at the press conference at Caltech on October 3.
For decades, the direct evidence of gravitational waves had belonged to the greatest challenges of modern physics. Einstein had predicted in 1916 that gravitational waves would exist, but thought them too weak to ever be detected. By the 1960s, technological advances such as the laser and new insights into possible astrophysical sources made it conceivable that gravitational waves might actually be detectable.
The first direct observation of gravitational waves by LIGO is an extraordinary demonstration of scientific vision and persistence.- Thomas F. Rosenbaum
The first person to build a gravitational-wave detector was Joseph Weber of the University of Maryland, building detectors in the 1960s using large aluminum cylinders, or bars, that would be driven to vibrate by passing gravitational waves. Other researchers like Ronald W. P. Drever at the University of Glasgow in Scotland followed.
When those experiments proved unsuccessful, the focus of the field shifted to a different type of detector called a gravitational-wave interferometer.
The very idea for LIGO came from Rainer Weiss in the early 1970’s when he, as associate professor of physics at MIT, wanted to explain gravitational waves to his students. Later on, he published his ideas in the paper "Electromagnetically Coupled Broadband Gravitational Antenna" which laid out the blueprint for the Laser Interferometer Gravitational-Wave Observatory. Ronald Drever's group, in 1973, in Glasgow, also began to build a prototype gravitational-wave interferometer of the sort first envisioned by LIGO co-founder Weiss.
Credit: LIGO
Transforming LIGO from concept to reality, would take another 20 years. In 1975, a meeting between Rainer Weiss and Kip Thorne of Caltech, a theoretical physicist studying gravitational waves since the late 1960s, would set into motion the development of one of the most complicated and risky scientific experiments ever conceived. Thorne’s contributions in setting the astrophysics goals were central to the design of the Observatories and the first instruments.
In 1979, Thorne and colleagues recruited Drever to Caltech as a professor of physics to initiate a Caltech research group in gravitational-wave experiments. In 1984, this group teamed up with Weiss's group at MIT and Thorne's Caltech theory group to create LIGO.
Credit: LIGO
In 1989, Weiss and Thorne, along with Drever and numerous others who were then working on the LIGO idea and gravitational wave physics, submitted a proposal for LIGO to the U.S. National Science Foundation (NSF). The proposal included the original design for the instrument by Rainer Weiss, updated to include engineering and technology innovations that had occurred in the following years. The NSF approved the proposal, and in 1994 construction began on the twin LIGO detectors in Hanford, Washington and Livingston, Louisiana.
That’s when Barry Barish joined in. Barish became LIGO Principal Investigator in 1994, helping to create, from a small group bringing up basic ideas, a large and broad team that actually delivered the observatories and hardware.
Barish also created the LIGO of today: a collaboration of approximately 1,200 scientists and engineers at about 100 institutions in 19 nations called the LIGO Scientific Collaboration (LSC), which conducted the scientific searches and analysis that led to the LIGO discovery.
"In addition to picking the right technologies and developing them, and securing funding, we needed to build a collaboration of the absolute best people possible for this almost impossible project. Forming an international collaboration, the LSC, enabled this. We attracted the best people from other universities and countries, creating an 'equal opportunity' collaboration, where there was no advantage to being at Caltech or MIT," said Barish.
We needed to build a collaboration of the absolute best people possible for this almost impossible project. - Barry Barish
All three Nobel Prize recipients emphasized the great importance of the whole collaboration of scientists to make the first direct evidence of gravitational waves possible. (LIGO Co-founder Ronald Drever passed away on March 7, 2017.)
"The prize rightfully belongs to the hundreds of LIGO scientists and engineers who built and perfected our complex gravitational-wave interferometers, and the hundreds of LIGO and Virgo scientists who found the gravitational-wave signals in LIGO's noisy data and extracted the waves' information. It is unfortunate that, due to the statutes of the Nobel Foundation, the prize has to go to no more than three people, when our marvelous discovery is the work of more than a thousand," Thorne said.
I am really moved by the vision of what’s going to be done over the coming decades.- Kip S. Thorne
On September 14, 2015, just after the Advanced LIGO interferometers began their first search for gravitational waves, they captured a strong signal which was revealed to come from the collision of two black holes 29 and 36 times more massive than the sun and located 1.3 billion light-years from Earth. The LIGO scientists announced this discovery to the world on February 11, 2016.
Since then, two additional detections of gravitational waves, again from merging black holes, were made on December 26, 2015, and January 4, 2017, and, on August 14, 2017, a fourth event was detected by LIGO and the European Virgo gravitational-wave detector which was announced at the end of September.
And there is yet much more expected to come in the future.
If you want to learn more about gravitational waves, from their theoretical prediction to the first detection and beyond, stay tuned!
Our next ScienceQuest edition will be about "The Mystery of Gravitational Waves".