Have you ever been annoyed by a humming sound, and you could never find out where it was coming from? Well, there is good news. You were not going mad. It was just the sound of the universe!
Astronomers say they have found evidence of a constant celestial "background hum". It was first heard by famous scientist Albert Einstein a century ago. The astronomers say this is a "really magical moment" in our understanding of space.
Daniel Reardon, an astronomer who works at Australia's Parkes Pulsar Timing Array project, says that the noise is probably the waves from "all the super-massive black hole systems whirling around each other, at the cores of galaxies everywhere in the universe."
Michael Keith, an astronomer in Europe, says this intergalactic hubbub is "like sitting in a noisy restaurant and hearing all these people talking".
Can you hear it sometimes?
