Gravitational waves Cardiff Uni detection explained

An international effort aided by Cardiff University has detected "gravitational waves" - first predicted to exist 100 years ago.

Albert Einstein proposed their existence as part of his Theory of General Relativity.

Gravitational waves are concentric ripples that squeeze and stretch the fabric of space-time. They are caused by the movement of immense mass, but most are so weak that they have no measurable effect.

Astrophysicist Deepali Lodhia explains.