Second wave: all about LIGO, black holes, gravitational ripples and more

By Tushna Commissariat

What an exciting week it has been, as the LIGO and Virgo collaborations announced that they have definitely detected a second gravitational wave event using the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) in the US.  These waves made their way into aLIGO early on Boxing Day last year (in fact it was still very late on Christmas Day in the US states where the twin detectors are located), a mere three months after the first gravitational-wave event was detected on 14 September 2015.

This event once again involved the collision and merger of two stellar-mass black holes, and since the “Boxing Day binary” is still on my mind, this week’s Red Folder is a collection of all the lovely images, videos, infographics and learning tools that have emerged since Wednesday.

LIGO physicist and comic artist Nutsinee Kijbunchoo has drawn a cartoon showing that while the researchers were excited about the swift second wave, they were a bit spoilt by the first, which was loud and clear – and could be seen by naked eye in the data. The black holes involved in the latest wave were smaller and a bit further away, meaning the signal was fainter, but actually lasted for longer in the detectors.

Cardiff University’s School of Physics and Astronomy – which is a key player in LIGO – has built this nice and clear interactive infographic on known stellar-mass black holes. These include X-ray binary black holes and those picked up by LIGO. You can change the parameters to see pre- and post-merger black holes, as well as change the scale depending on the black hole’s mass or size – go have a play with it.

A group of physics students and professors over at Montclair University in the US have built a great gravitational-wave resource titled the “Sounds of Spacetime“, which is basically a repository of sounds and simulations. “Our purpose is to explore the physics of gravitational waves via an analogy to audible sounds” reads the introductory page of the website and that is pretty much what the team has done. The team already has a dedicated page up about the second detection, which includes simulation videos of the merger and a variety of sound-files for the detected wave.

And for some interesting weekend reading, take a look at two different blogs written by members of the LIGO collaboration that both describe their latest detection. Daniel Williams at University of Glasgow, who blogs at Hazy Cosmic Jive, has a fab entry titled “The wave that stole Christmas“, which includes a great infographic of the merger. The Living LIGO blog written by Louisiana State University scientist Amber Stuver has a great account of the day in her post titled “Merry Christmas, LIGO: Another gravitational wave!“, so have a read and share the excitement.