COMMENT

The announcement of the detection of a neutron star merger, not only by gravitational wave experiments but also by myriad observatories, revealed what must have been the field’s worst kept secret. Between LIGO and VIRGO team members, observers following up on the gamma-ray burst detected by Fermi and those scrambling to look for optical counterparts of the gravitational wave, half of astronomy has been talking about this for months.

That’s the point, really. It’s by combining information from different observatories that we really get to understand what’s going on. In a single set of observations, we’ve seen an event never before observed, got clues into where the precious metals on Earth come from, bolstered explanations of gamma-ray bursts (but also raised new questions), found a new way of measuring the expansion of the Universe and shown that gravity and light travel at the same speed.