2004
Mars Exploration Rover Water Discoveries
At Meridiani
Planum, the Opportunity rover discovered large quantities of jarosite,
a mineral that contains iron, sulfur and trapped water. According to Steven Squyres, an astronomer at Cornell University and the
mission's principal investigator, the mineral simply could not have formed in
the absence water. Opportunity’s instruments also detected high levels of sulfur in
the rocks, probably in the form of sulfur salts and according to Benton Clark, another member of the
science team, these salts on Earth have only been observed to form only as a
result of water evaporation. Also, the Opportunity cameras revealed holes
within rocks, where according to the mission scientists, water must have once
formed mineral crystals that have since fallen out of the rocks. Finally, the Opportunity discovered numerous round pebbles scattered around the
surface but also as embedded in bedrock, indicating that they could only have
been formed in the presence of water.
Because the scientists had been at work for hours without eating, they
nicknamed these pebbles blueberries. Putting all of the observations together,
the conclusion was clear; the area examined by the Opoortunity rover was, at some point in its history, completed
submerged in water!
Meanwhile, on
the other side of the planet, in the Gusev Crater, the Spirit
rover drilled into a rock that scientists had nicknamed Humphrey, then examined the exposed area with a microscopic
imager. The pictures sent back to Earth
revealed fractures in the rock, filled with minerals –a sign that water had
once entered the rock. However, in
contrast to Opportunity’s discovery
that large amounts of water had once covred part of Meridiani Planum, Spirit’s
discovery suggested the presence only of tiny amounts of water. According to Ray Arvidson, Deputy Prinicipal Investigator for the rovers, the
water was mixed with the magma from which Humphrey
rock formed billions of years ago. As
the magma cooled and solidified into rock, the water separated from it, thus
producing the cracks and mineral deposits.
A
computer simulated image of a Mars Exloration Rover at work on the Martian
surface. Courtesy of the Planetary
Society. For more MER images, click
here http://www.planetary.org/mars/mer-images.html