Massachusetts Institute of Technology astrophysics professor Nergis Mavalvala speaks Thursday about the discovery of gravitational waves, first theorized by Albert Einstein a century ago.

WASHINGTON — It was just a tiny, almost imperceptible “chirp,” but it simultaneously opened humanity’s ears to the music of the cosmos and proved Einstein right again.

In what is being hailed as one of the biggest eureka moments in the history of physics, scientists announced Thursday that they have finally detected gravitational waves, the ripples in the fabric of space and time that Einstein predicted a century ago.

The news exhilarated astronomers and physicists. Because the evidence of gravitational waves is captured in audio form, the finding means astronomers will now be able to hear the soundtrack of the universe and listen as violent collisions reshape the cosmos.

It will be like going from silent movies to talkies, they said.

“Until this moment, we had our eyes on the sky and we couldn’t hear the music,” said Columbia University astrophysicist Szabolcs Marka, a member of the discovery team. “The skies will never be the same.”

An all-star international team of astrophysicists used an exquisitely sensitive, $1.1 billion set of twin instruments known as the Laser Interferometer Gravitational-wave Observatory, or LIGO, to detect a gravitational wave generated by the collision of two black holes 1.3 billion light-years from Earth.

“Einstein would be beaming,” said National Science Foundation director France Cordova.

The proof consisted of what scientists called a single chirp — in truth, it sounded more like a thud — that was picked up on Sept. 14. Astronomers played the recording at an overflowing news conference Thursday.

Some physicists said the finding is as big a deal as the 2012 discovery of the subatomic Higgs boson, known as the “God particle.”

Gravitational waves, postulated by Albert Einstein in 1916 as part of his theory of general relativity, are extraordinarily faint ripples in space-time, the continuum that combines both time and three-dimensional space. When massive objects like black holes or neutron stars collide, they generate gravitational waves that stretch space-time or cause it to bunch up like a fishing net.

Scientists found indirect proof of gravitational waves in the 1970s by studying the motion of two colliding stars.