
Starts With A Bang podcast #96 — The cosmic gravitational wave background
How scientists are hearing the gravitational background “hum” of the Universe for the very first time.
We all knew, if Einstein’s General Theory of Relativity were in fact the correct theory of gravity, that it would only be a matter of time before we detected one of its unmistakable predictions: that all throughout spacetime, a symphony (or cacophony) of gravitational waves would be rippling, creating a cosmic “hum” as all of the moving, accelerating masses generated gravitational waves. The intricate monitoring of the Universe’s greatest natural clocks, millisecond pulsars, would be one potential way to reveal this cosmic gravitational wave background.
But not many expected that here in 2023, we’d be announcing the first robust evidence for it already, and that future studies will reveal precisely what generates it and where it comes from. Yet here we are, with pulsar timing taking center stage as the second unique method to directly detect gravitational waves in our Universe!