May 7, 2019 - Science

Gravitational waves in real time

Artist's illustration of two black holes. Photo: LIGO/Caltech/MIT/Sonoma State

Artist's illustration of two black holes. Photo: LIGO/Caltech/MIT/Sonoma State

Ever since scientists first detected gravitational waves — ripples in the fabric of space and time created during the cataclysmic mergers of black holes and neutron stars — in 2015, discoveries have come in a slow trickle, released every few months.

Driving the news: Now we can expect those findings to come more like a firehose, and you can follow along in real time.

The big picture: Under previous guidelines, the researchers behind the LIGO and Virgo detectors would have waited to release discoveries until after thorough vetting and even peer review. But now, Virgo and LIGO are releasing possible detections as they occur.

  • Real-time release allows scientists to quickly work to make follow-up observations of any possible gravitational wave sources.
  • Members of the public can also follow along with the gravitational wave signals through the Gravitational Wave Events app and a database.
  • The app will use a gravitational wave "chirp" — the noise a gravitational wave would make if converted into sound waves — to alert users to new detections.

Details: The LIGO and Virgo detectors are now 40% more sensitive thanks to upgrades made following the last observing run.

  • Since coming back online in April, the collaboration has discovered 5 possible detections of gravitational waves.
  • If these detections are confirmed, it would suggest these kinds of cosmic crashes are even more common than originally thought.
  • One of those 5 possible detections appears to have been made by the collision of a black hole and a neutron star, which would be the first time such an event has been recorded.
  • The signal from that merger was relatively faint, but the detection bodes well for LIGO and Virgo's future sensitivity.
  • Scientists hope that the instruments will be able to pick up the signals from exploding supernovas as well.

How it works: LIGO and Virgo are designed to pick up the most minute signals from gravitational waves that warp space-time as they pass through the universe.

  • LIGO’s two L-shaped detectors each have a laser running down the arms. Mirrors at the ends of the arms bounce the light of the laser back to the middle.
  • If both make it back at the same time, no gravitational wave has passed, but if they don’t line up, there may have been a signal.
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