Scientists have detected a black hole collision. It lies some 3 billion light-years away, much farther than the previous two discoveries.
This is the third time since 2015 that these space-time vibrations known as gravitational waves from the merger of a pair of giant black holes has been observed via an instrument called LIGO (Laser Interferometer Gravitational-wave Observatory), which consists of a pair of detectors, one in Hanford, Washington, USA, and the other in Livingston, Louisiana, each designed to measure gravitational waves from distant cosmological events.
MIT senior research scientist David Shoemaker, spokesman for the LIGO team said: “We’re really moving from novelty to new observational science — a new astronomy of gravitational waves.”
Gravitational waves are ripples in the fabric of space, created by movements of massive objects. They were first postulated by Einstein in 1916.
“We’re starting to fill in the mass spectrum of black holes in the universe,” said David Reitze, director of the LIGO Laboratory, a smaller group of scientists headquartered at Caltech who built and run the observatory.
From visible and infrared all the way to X-rays and gamma rays, astronomers document the universe in different wavelengths of light.
Even if you can’t see these mysterious phenomena with telescopes, LIGO allows scientists to “hear” them.
Michael Landry, director of LIGO’s Hanford observatory said: “Such waves can be measured, because the distortions they produce look like changes in the length of any object they pass through”, he continued, “If I stretch the medium, the painting gets distorted.”
This new signal, called GW170104, was detected in the early morning of January 4 by the twin L-shaped detectors in Hanford, Washington and Livingston, La. The ripple was caused after two black holes, spinning around slowly toward each other, finally submitted to their shared gravitational tug and merged, thus making a single hole of 49 solar masses.
“Every time we find a new way of looking in the sky … we understand our universe in a whole new way, at a whole new level,” said Clifford Johnson, a theoretical physicist at USC who was not involved in the work.
After a journey lasting 3 billion years, those waves started shaking LIGO’s mirrors back and forth by a fraction of an atomic diameter 20 times a second. The pitch rose to 180 cycles per second in about a tenth of a second before cutting off.