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Ocean Lost

June 4, 2015

Oceanside property is tough to come by on modern-day Mars. But it might have been common when the planet was younger. In fact, an ocean with as much water as one of Earth’s oceans may have covered almost half of the planet’s northern hemisphere.

Today, Mars is cold, dry, and barren. But there’s plenty of evidence that it was once much warmer and wetter. The evidence includes a possible ancient shoreline that encircles much of the northern hemisphere.

A study published earlier this year suggested that almost four billion years ago, that shoreline ringed an ocean that contained about five million cubic miles of water — the equivalent of Earth’s Arctic Ocean.

The study was led by scientists at NASA’s Goddard Space Flight Center. They used three large ground-based telescopes to measure the ratio of two different forms of water in the present-day Martian atmosphere. Then they compared those results to the ratio found in a four-and-a-half-billion-year-old Martian meteorite. The comparison revealed how much water has disappeared from the Martian surface over the eons. Some of the water is frozen in the planet’s ice caps or in layers of permafrost, but most of it was lost to space.

The study concluded that the ancient ocean covered roughly a fifth of the planet’s surface, and was up to a mile deep — providing plenty of oceanfront real estate on the Red Planet.

We’ll talk about the oceans right here on Earth tomorrow.


Script by Damond Benningfield, Copyright 2015

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