LONDON, England (CNN) — The SARS virus might have originated in outer space, according to a scientist in Britain.
In a letter to The Lancet medical journal, professor Chandra Wickramasinghe of Cardiff University suggests the virus was introduced to Earth on a comet or meteorite.
Comets are known to contain many organic chemicals as well as water.
But international scientists are still undecided about research from 1996 purporting to show ancient bacterial forms in a meteorite from Mars.
The professor and his team estimate a tonne of bacterial material falls to Earth from space each day.
To support his theory, the professor highlights the unique nature and sudden appearance of SARS in China.
He points to other mysterious modern epidemics like the Plague of Athens and the influenza pandemic of 1917-19 as also originating from the skies.