"Blue" and "green" and then "Red" planet?
Nasa scientists are presenting new and compelling evidence that says Mars once had a considerable ancient ocean,
covering almost half of the top of the planet.
The huge body of water spread over a fifth of the planet’s surface, as great a portion as the Atlantic covers the Earth, and was a mile deep in places. In total, the ocean held 20 million cubic kilometres of water, or more than is found in the Arctic Ocean, the researchers found.
This adds to the already mounting evidence that Mars was a pretty wet planet in its adolescent
millions of years of age. The scientists observed different water molecules in the
Martian air and their changes at various times of the year and in various regions of the planet.
The infrared maps show that water near the Martian ice caps is enriched with deuterium. The high concentration means that Mars must have lost a vast amount of water in the past, equivalent to more than six times that now locked up in the planet’s frozen ice caps.
The scientists calculate that the amount of water was enough to create a global ocean that covered the entire surface of Mars to a depth of 137m. But Mars was probably never completely submerged. Based on the Martian terrain today, the scientists believe the water pooled into a much deeper ocean in the low-lying northern plains, creating an ocean that covered nearly a fifth of the planet’s surface. The Atlantic, by comparison, covers about 17% of Earth’s surface.
Video of Nasa's findings below the fold.