By Hamish Johnston

Yesterday we announced the winner of the Physics World 2016 Breakthrough of the Year, which went to the LIGO Scientific Collaboration for its revolutionary, first ever direct observations of gravitational waves. I caught up with six LIGO scientists in the above video Hangout and asked them what it was like when they first realized that they had detected gravitational waves emanating from two coalescing black holes 1.3 billion light-years away.

There was no eureka moment according to Mike Landry, who is based at LIGO’s facility in Hanford, Washington. Instead, the physicists had to first work out whether the signal they saw was actually a test signal that had been injected into the detectors.

Eventually it dawned on the team that the signal was real and the discovery was sealed when the LIGO Scientific Collaboration Spokesperson Gabriela González showed up at work with a “very large cake”.

Also in the video are LIGO collaborators Brian O’Reilly, Maria Alessandra Papa, Sheila Rowan and Joseph Giaime. As well as talking about the first detection, we also chatted about what’s next for LIGO and when we can expect to see a gravitational-wave map of the sky.