One, two and now three historic waves have come from deep space, confirmed again by a chirping sound that was like music to the soul for the worldwide group of scientists waiting for it. An international research team, including 8 Greek scientists, announced the third detection of gravitational waves — ripples in the fabric of space and time, first predicted by Albert Einstein more than a century ago.
The Laser Interferometer Gravitational-wave Observatory (LIGO) made the detection Jan. 4, 2017, demonstrating that a new window in astronomy has been firmly opened.
Gravitational waves pass through Earth and can be “heard” by the extremely sensitive LIGO detectors. As was the case with the first two detections, the waves were generated when two black holes merged to form a larger black hole. The long-awaited triumph in September 2015 of the first-ever direct observation of gravitational waves completed Einstein’s vision of a universe in which space and time are interwoven and dynamic. The third and latest detection points to merging black holes that are twice as far away from Earth as the two earlier pairs — about 3 billion light-years away. And this time the two black holes were unequal in size, one significantly lighter than the other. They merged into a black hole whose size is in the middle of the other two merged black hole pairs.
The 8 Greek researchers are:
• Michael Agathos
• K. Chatziioannou
• Vicky Kalogera from Northwestern University
• Erotokritos Katsavounidis, a Senior Research Scientist at MIT’s Kavli Institute
• Antonis Kontos from MIT
• C. Markakis
• Andrew Melatos from the University of Melbourne
• Mary Sakkelariadou from King’s College
“Our handful of detections so far is revealing an intriguing black hole population we did not know existed until now,” said Northwestern’s Vicky Kalogera, a senior astrophysicist with the LIGO Scientific Collaboration (LSC), which conducts research related to the twin LIGO detectors, located in the U.S.