Artist's illustration of a future gravitational wave-detecting satellite, part of the LISA program. Credit: Max Planck Institute for Gravitational Physics/LISA Consortium
In the grand scheme of things, the study of gravitational waves is very new; the first detection of a gravitational wave, by the Laser Interferometer Gravitational Wave Observatory, came less than a decade ago. The detectors that could discern new forms of gravitational waves also have construction timelines that end in the 2030s, making it reasonable to worry that the science has always been destined to advance at a snail's pace.
Well, we need not have worried about that. Gravitational waves are already having a significant impact on astronomy overall, and the science behind their study is advancing at an astonishing pace.
That's the main takeaway from a new paper so collaborative that its three authors are themselves collaborations: the LiGO, Virgo, and KAGRA Collaborations. These researchers are scattered all over the world, including at labs in the United States, Italy, and Japan.
Their work has paid real dividends. The new catalog of observations adds 128 new collision events between two black holes or between a black hole and a neutron star. Not so long ago, proving that such an event could exist at all was a big deal. This catalog is quite a remarkable achievement.
The new detections result from the diligence of those doing the searching and tireless efforts to improve the fidelity of existing detectors. Recent upgrades have improved sensitivity by as much as 25%. This not only makes it possible to pull fainter signals out of background noise, fundamentally increasing the number of events that can be seen, but also unlocks new forms of investigation into the nature of spacetime itself.
That's true both directly, through gravitational wave detections themselves, and indirectly, through easier study of associated events. We recently reported on a new proposition to investigate the nature of spacetime by looking at tiny black hole "morsels," the finding of which is only possible because they are formed near the binary black hole collisions that gravitational wave detectors can now pinpoint.
In just nine years or so, gravitational wave detections have become massively more precise, diverse, and responsive. All we need to do now is wait for the Laser Interferometer Space Antenna (LISA) to begin operating, at which point the study can expand to the supermassive black holes that form galaxies.
These detections reveal the mechanics of the Big Bang and the earliest stages of matter in the universe through supermassive black holes and other potentially primordial features of the universe.