There's something a little off about our theory of the universe. Almost everything fits, but there's a fly in the cosmic ointment, a particle of sand in the infinite sandwich. Some scientists think the culprit might be gravity—and that subtle ripples in the fabric of space-time could help us find the missing piece.
source https://phys.org/news/2020-12-ripples-space-time-clues-components-universe.html
