In February 2016, Albert Einstein made history, again. That’s when physicists announced they’d finally observed what the great scientist’s theories had predicted 100 years earlier: gravitational waves.
The first confirmed sighting of gravitational waves — distortions of space-time, literally ripples in the fabric of the universe — was a tremendous feat, earning Nobel Prizes for the key developers of the Laser Interferometer Gravitational-wave Observatory (LIGO). The waves’ ultimate source was just as fantastic as the engineering that went into detecting them: two black holes smashing together, their enormous gravities sending undulations throughout the cosmos.
This achievement, the culmination of a multidecade-long effort, was justifiably celebrated. But while it resolved the long-standing issue of whether gravitational waves existed, it also marked a starting point for a whole new journey.
Before, astronomy had been based solely on studies of electromagnetic radiation and exotic particles like neutrinos and cosmic rays. But the tiny gravitational ripples, along with our recently acquired ability to see them, ushered in a novel way to study the universe.
Gravitational waves offer independent cross-checks on established avenues of research, while revealing phenomena we haven’t seen before — and may not have imagined. In addition to the great (and previously unavailable) views we now have of the violent crashes between black holes and other superdense objects, gravitational waves may also clue us in to what transpired within a split second of the Big Bang itself. They could show us, moreover, how the universe has been expanding ever since. And while the sighting of gravitational waves offered a vindication of Einstein’s hallowed principles, researchers can now subject general relativity to its most stringent tests yet, possibly revealing its shortcomings.
