[ music ]
Scientists have suspected for decades that ancient Mars was a much warmer, wetter environment,
but estimates of just how much water Mars has lost over its four-and-a-half-billion-year history vary widely.
Now, researchers at NASA's Goddard Space Flight Center have made the best estimate to date
by measuring the atmospheric ratio of normal to heavy water molecules near the Martian polar caps.
The new measurements suggest that at least twenty percent of the Martian surface was once covered by water,
contained in an ocean with a maximum depth of about one mile.
Over time, nearly ninety percent of this ocean was lost to space, with the remainder locked up today in Mars' north and south polar caps.
This new picture of early Mars is considerably wetter than many previous isotopic estimates,
and suggests that water persisted on the Martian surface for billions of years,
raising the odds for the ancient habitability of the Red Planet.
[ music ]
[ satellite beeping ]