A few weeks ago, NASA scientists announced they'd discovered something completely new on the surface of the Red Planet. Now they know what it is —and they're calling it the most powerful evidence for liquid water on Mars ever encountered by the Opportunity Rover.
The unassuming mineral vein, nicknamed "Homestake" by its discoverers, measures just 18 inches long and is about the width of your thumb, but analyses of its composition revealed the outcropping to be rich in calcium and sulfur, which strongly suggest that it's comprised of a mineral called gypsum. And while gypsum had previously been observed on Mars' surface from space, there's simply no substitute for encountering and analyzing a sample right at the source.
"There was a fracture in the rock, water flowed through it, gypsum was precipitated from the water. End of story," said Steve Squyres, Mars Exploration principal investigator at Cornell University. "There's no ambiguity about this, and this is what makes it so cool."
The other thing that makes this discovery so exciting is that gypsum could have formed in less acidic conditions than minerals encountered on Mars' surface in the past. Less acidic water, reason scientists, equals a greater chance of life; and a greater chance of life equals an increased likelihood of mindblowing Martian discoveries in the months and years ahead.
A false color image of the Homestake Vein — generated by photographing specific wavelengths of light — can be seen up top. Compare this image to the true color image featured here, and you can get a feel for how the false coloring makes it easier for scientists to differentiate between the visible minerals in and around the vein.