MARS: A WATER WORLD AFTER ALL
What everyone has known for years — that Mars is a dry, frozen place — turned out to be a hasty judgment when a student from Nepal noticed something odd about Martian hillsides.
Yes, Luju Ojha found running water on the Red Planet — at the age of 25.
The Georgia Tech student, who chose science after he couldn’t make money as a guitarist in a death-metal band, figured out how to get new information from an old source, the Mars Reconnaissance Orbiter. The NASA satellite has been taking photos of Mars for nine years.
Ojha was at the University of Arizona in 2010 when he first noticed the 100-metre-long dark stripes on hillsides, which appeared and disappeared with the seasons. But Ojha’s breakthrough lay in figuring out how to analyze the chemical content of those stripes. They turned out to be hydrated salts, or salts that have been exposed to water.
And like road salt on Earth, the salts can keep water liquid well below its normal freezing point, at temperatures Mars often reaches during its summers. NASA calls the salts “likely a mixture of magnesium perchlorate, magnesium chlorate and sodium perchlorate.” These show up in Earth deserts, too.
“It took multiple spacecraft over several years to solve this mystery, and now we know there is liquid water on the surface of this cold, desert planet,” Michael Meyer, lead scientist for NASA’s Mars Exploration Program, told a news conference. “It seems that the more we study Mars, the more we learn how life could be supported and where there are resources to support life in the future.”
But there are smaller findings flowing from Mars from the Curiosity rover. “In some ways we get lulled into this mode of, ‘Oh, yeah, more information from Mars’,” says Chris Herd.
“We’re investigating Mars at a level of detail that we have never done before. We’re doing things that people wish they could do with rocks on the Earth. The rover is going through the stack of sedimentary rocks, and it’s zapping, firing its laser. Thousands of laser shots now. And it is getting all this information on the composition of all the layers in these sedimentary rocks.
“That’s a stratigrapher’s dream.” The many layers in these rocks are pages in the complex history book of the planet. Some show where layers of blowing sands have built up in layers and formed rock, and others appear to be layers formed under water, when Mars still had lakes and rivers billions of years ago.
“It’s not just the same thing over and over. They are seeing significant variety and differences in … the composition of these rocks.”
“The amount of data coming back is unprecedented. So even though we are not hearing constant PR sound bites from Mars, (Curiosity) is chugging away and quietly revolutionizing our understand of Mars geology.”