mdsolar writes After six years of planetary observations, scientists at NASA say they have found convincing new evidence that ancient Mars had an ocean. It was probably the size of the Arctic Ocean, larger than previously estimated, the researchers reported on Thursday. The body of water spread across the low-lying plain of the planet's northern hemisphere for millions of years, they said. If confirmed, the findings would add significantly to scientists' understanding of the planet's history and lend new weight to the view that ancient Mars had everything needed for life to emerge. Update: 03/05 22:42 GMT by T : Correction: that headline should have read "Arctic" initially, rather than Antarctic.