• Scientists on Wednesday unveiled evidence that gravitational waves, the ripples in the fabric of space-time predicted by Albert Einstein more than a century ago, are permeating the universe at low frequencies - creating a cosmic background hum.
  • Einstein in 1916 proposed the existence of gravitational waves as an outgrowth of his ground-breaking general theory of relativity, which depicted gravity as the distortion of space and time by matter. Until their detection in 2016, scientists had found only indirect evidence of their existence, beginning in the 1970s.
  • The discovery was announced seven years after researchers announced that they had first detected the existence of gravitational waves generated by two distant black holes - extraordinarily dense objects with gravity so strong that not even light can escape.