The hunt for gravitational waves is back on. After a little over a year of upgrades, the Laser Interferometer Gravitational-Wave Observatory (LIGO) is preparing for its third run of observations.
Gravitational waves are ripples in space-time that emanate from massive objects as they move, and that stretch and squeeze everything in their path. LIGO detects them using powerful lasers shot onto mirrors and sent through long tunnels. So far, it has spotted the signals resulting from 10 pairs of black holes merging and one pair of neutron stars smashing together.
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During its year off, LIGO was upgraded with new mirrors, panels to control any stray light that might leak into the detector and new amplifiers to make the lasers even more powerful. These updates should extend LIGO’s reach into the cosmos from about 326 million light years to about 391 million.
“One gravitational wave hunter hopes to see a black hole and neutron star merge. It should be quite a show”
We should also have more detectors than before. LIGO itself consists of a pair, one in Hanford, Washington state, and one in Livingston, Louisiana. There is also a third, the Virgo detector in Italy. Researchers hope a fourth will be up and running in Japan by the end of the new observation period. Each addition helps pin down the origins of a signal so we know where to point telescopes for follow-up observations.
Gravitational wave hunters are excited at the prospect of spotting something new with their upgraded systems. Joseph Giaime, the head of LIGO Livingston, hopes to see a black hole and a neutron star merge, rather than two objects of the same sort. “It should be quite a show as the neutron star gets torn apart,” he says.
The upgraded detectors are set to turn on around February 2019 and continue running for a full year. If all goes to plan, we should see a new gravitational wave event at least every couple of weeks.
This article appeared in print under the headline “News Preview 2019: LIGO spies more space oddities”
