On September 14, 2015, gravitational waves from the smashup of two black holes reached Earth. And for the first time, a scientific instrument was ready to detect this type of signal. This was a massive discovery: Astronomers had never before seen the undulations of spacetime—that stuff in which everything in the universe swims. The detection validated a prediction Albert Einstein had made a century before and resulted in a Nobel prize. But it took five months for scientists to vet, validate, and interpret that discovery confidently enough that they could go public, which they finally did in February 2016.

Gravitational waves ripple through the universe every time an object with mass accelerates. Jump up and down: Congratulations, you made some. Your puny waves may be too weak to register with LIGO, the Laser Interferometer Gravitational-Wave Observatory, but LIGO can pick up the stretching and squeezing of spacetime that happens when, say, black holes crash into each other.

And it has: Astronomers with LIGO and its new collaborating instrument Virgo have now caught waves from six violent cosmic collisions. Today, the team is optimizing detection algorithms, and developing new tools through machine learning, so that they can shrink the time between when a wave bumps into Earth and when earthly astronomers around the world—and you—know about it.

Identifying gravitational wave candidates more quickly will improve astronomers' ability to study the phenomena that produce them. After all, LIGO isn’t a “Can we find a gravitational wave? y/n” machine, or at least it’s not just that. Scientists want to know what those gravitational waves reveal about black holes, neutron stars, pulsars, cataclysmic collisions, quick orbits, and, you know, the nature of space and time.

Key to this understanding is interpreting LIGO’s observations in the context of electromagnetic data—visible light, infrared radiation, radio waves, X-ray emissions, etc. But to capture that light, astronomers have to know when a gravitational wave event is happening, so that they can tell telescopes to turn toward the right spot in space.

That kind of data collection—called “multi-messenger astronomy”—happened for the first time in August 2017. Two neutron stars spiraled toward and ultimately crashed into each other, releasing not just gravitational waves for LIGO but also gamma rays, X-rays, ultraviolet and infrared radiation, visible light, and radio waves for telescopes, which got word of the gravitational waves in time to collect data. Getting a quicker jump on these signals means scientists can see the phenomena in action, and then interpret that action, rather than just its aftermath (or nothing at all).

The LIGO collaboration has already accelerated how fast it can send “Hey, look over there!” alerts. For the first two discoveries, there was a more than day-long gap between when waves arrived and when notices went to a network of scientists. For the inspiraling neutron stars, though, that lag was just over 30 minutes.

It would happen a lot faster if it weren't for humans, who still weigh in on the software's analysis. “The automated part can be done as quickly as 15 seconds at this point,” says Chad Hanna, an astrophysicist at Penn State. Hanna works specifically on software that finds gravitational waves from “compact binary” mergers—objects like black holes or neutron stars smashing together. He and other LIGOers have created templates—models of how gravitational waves from these collisions should look—for a range of collision scenarios. “Then we go looking for that exact thing,” says Hanna (or, really, those many, many possible exact things). The technique is formally called "matched filtering."

Other groups develop data pipelines to search for the continuous waves, the chorus of background waves, and bursty waves of unknown origin. Sergey Klimenko, of the University of Florida, works on the unknowns. “We developed a method that does not require you to know in advance what are the properties of your source,” he says. “It makes sense because nature may have some surprises for us.” This method looks for spacetime signals that show up the same at the LIGO site in Louisiana, the one in Washington state, and, recently, a Virgo location in Pisa.