Nasa mission 'senses first Marsquake'

Nasa's InSight lander has detected its first seismic event on Mars. The faint rumble was picked up by the probe's sensors on 6 April. It is the first seismic signal detected on the surface of a planetary body other than the Earth and its Moon. Prof Tom Pike, from Imperial College London, who built the high-frequency elements in InSight's seismometer instrument, discussed the discovery with our science correspondent Jonathan Amos.