Description
Pulsar Timing Array (PTA) collaborations use a collection of pulsars in the Milky Way to detect gravitational waves in the nanohertz band by measuring tiny shifts in pulse arrival times. In this talk, I will briefly summarise the recent strong evidence for a gravitational wave background, together with astrophysical and cosmological interpretations of the PTA observation. I will conclude by highlighting prospects for discriminating between the possible origins of the observed signal.
