A lump of space rock that shattered the pre-dawn calm of the Moroccan desert with a fireball and double sonic boom last year was knocked off Mars in a cosmic collision roughly 700,000 years ago.
The date of the Martian impact means the rock was flung into space and began its journey to Earth when the shared ancestor of modern humans and Neanderthals was still alive and well in Africa.
Scientists dated the collision through a fresh analysis of the remains of the meteorite, based on the exposure of its elements to intense cosmic rays during its journey through space.
The Tissint meteorite, as it is known, is particularly valuable because it was recovered before it had suffered any weathering on Earth. Witnesses said it split in two as it fell to Earth and landed in the desert near Tata in the early hours of July 18th last year. – (Guardian service)