Physics is this close to understanding the entire universe. And what lives in this gap? Many physicists think it’s the elusive graviton—the quantum particle of gravity—whose discovery will finally ...

Gravitons, the particle of quantum gravity, may be impossible to detect. To progress to the next level in understanding reality, we need to combine quantum mechanics and Einstein’s general relativity.

(via PBS Space Time) Physicists have long believed that detecting the particle of gravity—the graviton—was fundamentally impossible, with the universe itself seeming to block every direct attempt.