Look What We Found on Mars: Curiosity Rover Serves Up Awesome Science
Posted by admin on September 26, 2013
- News from NASA’s Curiosity rover, currently traveling across the surface of Mars, often comes out piecemeal. We learn what the probe did on one particular day but rarely how that fits in with our larger understanding of the Red Planet and its history.
Today, the scientists working with Curiosity offer a trove of detailed analyses. The have simultaneously published five papers in Science as well as an additional article in the Journal of Geophysical Research: Planets that incorporate everything the rover learned in its first months working at Gale crater.
“These papers, in a nutshell, present our summary of using the Curiosity laboratory for the first time on Mars,” said geologist John Grotzinger, the project scientist for the mission.
The findings offer a look at the soil, composition, mineralogy, and history of an area known as Rocknest, which Curiosity visited in October and November 2012. While there, the rover got to try out many of its instruments for the first time during a battery of testing. It shot the Martian surface with lasers, X-rays, charged particles, and even took five scoops from the surface to heat in its internal oven.
Here, we’ll take a look at the details the science team has provided in their glut of new papers. Much of this information will come in handy as Curiosity roves on to the base of Mount Sharp, its eventual target. The data will give context and insight into the next things the probe will find and could help unravel the complex history of water and its disappearance from Mars.
- Curiosity’s first investigations of a rock on Mars turned up something rather exciting: a type of rock never before seen on the Red Planet. The target, nicknamed Jake Matijevic or JM for short, is similar to rocks on Earth known as mugearites. These are found on oceanic islands and continental rifts, suggestive of the idea that JM could have been generated by magmas deep within the planet. Scientists still debate how long Mars had tectonic processes and how active they were, but this rock points to the fact that the ancient planet was fairly dynamic.
- Curiosity bombarded the Martian soil with X-rays in order to determine what sorts of minerals are there. The rover found crystals such as quartz and feldspar as well as non-crystalline materials that look like a substance called hisingerite. The science team concludes that the surface at Gale crater strongly resembles volcanic soils on Earth in places like Mauna Kea, Hawaii.
- Early in Curiosity’s mission, the science team let it slip that they had uncovered some very important finding. Speculation centered on the idea that the rover had found organic molecules, a potential indicator of past life. The eventual announcement — that the probe had found some simple organics that may or may not have come from Mars — wasn’t quite that exciting. But the scientists have analyzed those simple molecules it did find.
Curiosity detected chlorinated hydrocarbons, which are chemicals composed of both carbon and chlorine. A detailed look at the individual components suggests the chlorine in these molecules originated on Mars, though it’s still unclear if the carbon is indigenous or arrived as a contaminant from Earth. But the team has determined with high probability that the soil at Gale crater contains a large amount of perchlorates.
Perchlorates are chemical salts that release oxygen when heated. The reason this is important is the 1970s Viking missions heated Martian soil in order to see if it contained any simple life, and those results have been inconclusive and controversial for decades. But the presence of perchlorates would have messed with those original findings, destroying any organic molecules and leaving open the question of whether or not Viking detected any carbon. Because they are salts, perchlorates could have also formed briny water on ancient Mars and served as an energy source for microbes, as they do on Earth. So Curiosity’s detection of perchlorates may vindicate an old experiment and increase the habitability of Mars in the past.
If future Curiosity experiments find carbon on Mars, it doesn’t automatically indicate life past or present. A fair amount of organic carbon has arrived on the planet over millions of years during asteroid impacts.
- Curiosity is carrying a microwave-sized instrument called the Sample Analysis at Mars (SAM). It is basically a very complicated scientific Easy-Bake Oven capable of heating samples of soil to more than 800 degrees Celsius and seeing what comes out. In analyzing its first soil sample, SAM found carbon dioxide, oxygen, and molecular water, which had been chemically bound in the sandy material.
The analysis is useful in deciphering Mars’ past because these sand grains hold a record of many chemical and geological processes. And because of the presence of these chemicals, the science team suggests fine-grained soil “could be a good source of water, CO2, and other volatiles to be leveraged by future human explorers on Mars.”
- Much of what we know about the Red Planet comes from orbital observations. Curiosity’s value on Mars is its ability to get up close and literally touch the soil. Looking at the composition and mineralogy of the soil is like reading the “history of the Martian crust, its meteoritic bombardment, and the physical and chemical weathering processes that transformed” it, wrote the authors of one paper.
Curiosity used its ChemCam instrument to analyze the Martian soil and create an inventory of the chemicals within it. These findings will come in handy when Curiosity roves over to the base of Mount Sharp and studies the processes that changed the planet from a warm and wet one to a cold and dry one.
- When Curiosity looked closely at the sand at Rocknest, “some grains showed bright glints in the Martian sunlight,” wrote the authors of one paper in Science.
A detailed analysis using X-rays showed that the Martian soil is made of roughly 55 percent crystalline material. Scientists found that the composition of the sand at Gale Crater was similar to that at other sites on Mars, such as those explored by the Spirit and Opportunity rovers. This suggests the sands of Mars have been blowing around for a good deal of time, long enough to have a relatively similar mix of material on a global scale.
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