Scientists hunting for gravitational waves — ripples in the fabric of space and time sent out by cataclysmic collisions — have had a busy month.
The impact: The LIGO and Virgo observatories tasked with detecting these waves began their newest observing run on April 1, and they've already found evidence of 5 possible gravitational wave signals. The observatories are 40% more sensitive following upgrades made since the last observing run ended.
The big question: By detecting these gravitational waves on Earth, scientists can work backward to find out more about what created those ripples, giving us new insights into some of the most extreme objects in the universe.
“The entire astrophysics community is very excited that we’ve already seen 5 candidate events in four weeks.”— LIGO astrophysicist Jess McIver said during a press conference Thursday
Details: Three of the gravitational wave signals are thought to be from two merging black holes, with the fourth believed to have been emitted by colliding neutron stars. The fifth, and perhaps most exciting, seems to be from the merger of a black hole and a neutron star.
- If confirmed, this will mark the first neutron star-black hole merger ever documented.
All five signals still need to be confirmed through follow-up analysis.
How it works: LIGO and Virgo are able to detect these gravitational waves through very precise instrumentation. When a gravitational wave passes through Earth’s part of space, every atom warps ever so slightly.
- A laser runs down the arms of LIGO and Virgo’s three L-shaped detectors. Once the laser hits the end of the detector, a mirror bounces the light back to the middle.
- If no gravitational wave has passed through, the beams of light should arrive back at the bend in the L at the same time, but if there’s a mismatch, a gravitational wave may have been observed.
What’s next: Unlike earlier observing campaigns, the two observatories have started releasing their detections in real time, allowing other observatories to make follow-up observations.