The scientists’ report in the January 25th issue of Nature proposes that volcanic magma rising to the surface of Mars contained water. Some rocks formed by volcanic activity were then ejected from Mars, becoming meteorites, and wound up here on Earth. They have since been analyzed for their mineral content and evidence of water.

Mars on Earth

By examining the chemical composition of the meteorites from Mars, scientists can determine how much water was necessary to form certain types of crystals. Many mineral compounds must have a specific amount of water in order to form. Grove and McSween analyzed a meteorite, called Shergotty, that was discovered in India in 1865. It is one of 15 proven Mars meteorites that have landed on Earth.

Shergotty is relatively young in galactic terms—175 million years old. It was ejected from Mars after a meteorite possibly slammed into a volcanic region on the Red Planet and sent the 11-pound (5 kg) stone on its trip to Earth.

Martian rocks similar to the Shergotty meteorite provide clues to where water may be on the planet. According to Dr. Grove, there are three steps that allow for water vapor to reach the surface of Mars through volcanic activity.

Step one: Deep inside Mars magma picks up water from an deep source. Two: As the magma rises closer to the surface, where pressure and heat are reduced, crystals form from interaction with the water in the magma. In step three, as the magma rises to the surface through volcanoes on Mars, the water within turns into vapor and fizzes out of the cooling magma like bubbles from a shaken bottle of soda.

Recent observations by the Mars Global Surveyor satellite suggests that 3.5 billion years ago a very young Mars was once covered with oceans and rivers. So the research conducted on the Shergotty meteorite by Grove and McSween is searching for signs of water in more recent times.

Where’s the Water?

The scientists discovered that the earliest crystallizing minerals in the Shergotty meteorite would have needed at least 2 percent water content to form. Also, the presence of certain elements within the meteorite indicate relatively high water content at one time.

“The only way you can reproduce the unique chemical composition of these minerals,” says Grove, “is to have water present.”

So, where is the water on Mars now? The Shergotty meteorite from Mars, being only 175 million years old, is much too young to give any clues of the possibly vast oceans and rivers that may have once flowed on Mars 3 billion or more years ago. According to Dr Grove, “the thing that is exciting about this rock (Shergotty) is that water is being recycled through the planet.” Where the water, if any, is on Mars is still up for discovery.