When new detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) are turned on next year, astronomers may be able to detect hundreds of black holes, thanks to new research by a team of scientists from Cardiff University.
If all goes well, their research will help scientists look at data and pick out exactly which pieces of it show gravitational waves, those ripples in the fabric of space-time that black holes make when they collide.
Why are we looking for gravitational waves? Since black holes don't illuminate light and actually trap light (and everything else) within them, we can't directly see them. However, LIGO's detectors will search for these waves that show us where the remnants of black holes are after they collide.
The Cardiff research, which is a theoretical model, helps by showing scientists what to look for once LIGO starts spitting out data. Because black holes spin so quickly, their orbits wobble. Those wobbles create gravitational waves.
"Our model aims to predict this behavior and help scientists find the signals in the detector data," says Dr. Mark Hannam from the School of Physics and Astronomy at the university.
Hannam also described how an international team of scientists will work together in interpreting LIGO's data.
"Sometimes the orbits of these spinning black holes look completely tangled up, like a ball of string," says Hannam. "But if you imagine whirling around with the black holes, then it all looks much clearer, and we can write down equations to describe what is happening."
According to Hannam, these equations virtually put us inside the black hole. He compared it to a child riding a merry-go-round: for those watching the child spin around, if the child lifts up a hand, it looks like a blur. However, someone riding beside the child sees the hand clearly.
Although researchers programmed the equations into computer codes used by LIGO scientists, they're still racing against the clock to finish their work by the time LIGO gets switched on next year. The equation still does not factor in what happens to black holes' spins when they collide. That will require many more larger simulations.
LIGO is a joint project between scientists at MIT, CalTech and other universities worldwide. It began observations in its search for gravitational waves in 2002, but after it found none, it stopped looking in 2010. However, its older detectors are being replaced with detectors using newer technology with higher sensitivities.
