Category Archives: Mars

Mars, Mars Reconnaissance Orbiter

How Science Works: Mars Edition

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Mars Scientists Keep Finding Evidence for Water: This is Good!

These dark, narrow, 100 meter-long streaks called recurring slope lineae flowing downhill on Mars are inferred to have been formed by contemporary flowing water. Recently, planetary scientists detected hydrated salts on these slopes at Hale crater, corroborating their original hypothesis that the streaks are indeed formed by liquid water. The blue color seen upslope of the dark streaks are thought not to be related to their formation, but instead are from the presence of the mineral pyroxene. The image is produced by draping an orthorectified (Infrared-Red-Blue/Green(IRB)) false color image (ESP_030570_1440) on a Digital Terrain Model (DTM) of the same site produced by High Resolution Imaging Science Experiment (University of Arizona). Vertical exaggeration is 1.5. Credits: NASA/JPL/University of Arizona
These dark, narrow, 100 meter-long streaks called recurring slope lineae flowing downhill on Mars are inferred to have been formed by contemporary flowing water. Recently, planetary scientists detected hydrated salts on these slopes at Hale crater, corroborating their original hypothesis that the streaks are indeed formed by liquid water. The blue color seen upslope of the dark streaks are thought not to be related to their formation, but instead are from the presence of the mineral pyroxene. 
Credits: NASA/JPL/University of Arizona

While I was on travel this past week, the Mars water announcement occurred. It set off a lot of interest among people interested in Mars science, plus a bunch of commentary about “what, again?” somehow implying that we only need one announcement of Mars water and that’s that. There were worse reactions, including an incredibly stupid one from a so-called “entertainment” radio talk show host who claimed the announcement was a leftist hoax.

So, I just thought I’d tell you that science doesn’t work the way some people think it does. It’s not a leftist or rightist hoax. Although, I can certainly understand how an undereducated oaf who probably flunked his “Rocks for Jocks” class in college might think so. Particularly one who has made a career of hoaxing radio audiences for years.

Let’s take the Mars water discovery. It’s not just one discovery. It’s many small steps that add up to a final confirmation of water on the Red Planet. Mars is not a place where you can just look at it and see shimmering lakes of water. The place makes you work for your discoveries. Since nobody has walked on the planet and seen it “up close and personal”, we don’t have the same first-person evidence that you get here on Earth. Here, you can simply walk up to the lake or river or ocean, put your hand into it and get it wet. You know it’s water. You can take samples, measure it, figure out what minerals are dissolved in it, and so on.

You can also see what water DOES on our planet first-hand.  Just go visit some geological formations near your home and learn about how they came to be. I just drove through several canyonland areas in the U.S. Southwest, with many landforms carved, deposited, and cemented by water. There are rocks and minerals that need water to exist the way they are. Geologists have figured this out, and you can learn from their work.

Studying Water on Mars

Dark narrow streaks, called "recurring slope lineae," emanate from the walls of Garni Crater on Mars, in this view constructed from observations by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.
Dark narrow streaks, called “recurring slope lineae,” emanate from the walls of Garni Crater on Mars, in this view constructed from observations by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter.

On Mars, we don’t have the luxury—yet—of being able to touch the land or feel for the water. So, we use our robotic probes to test the surface rocks, image the landforms, and do chemistry tests on the rocks that are on the surface. Imaging shows us forms that look like they were formed by water. The chemistry tests give more data pointing toward the existence of water on Mars.

So, each time that an experiment on Mars has proven the existence of water in the samples and images, the finding is announced. And, it should be. Each test is a step toward proving that water is part of Mars (and has been). And, each step has been announced, also as it should be. This is the way science works — and taxpayers who whine about how “scientists are always finding water on Mars” — are showing their ignorance of the process they’re paying for. They should be happy that scientists ARE telling us about each step of the process that it takes to determine the existence and amounts of water on Mars. This is also how science works.

The next steps will be to figure out more about the water, which may (I stress MAY) give us some clue about whether or not life ever existed on the planet. There’s no proof that it did, or didn’t. That will take more investigative science. Which is also how science works.

Want to read more about the science of Mars exploration?  Here are some links, from people who are doing the science.

Journey to Mars

Mars Reconnaissance Orbiter

NASA and Mars

The more you know, the better you’ll understand the scientific process of Mars exploration.

Curiosity, Mars

Reading the Rock Record on Mars

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Mars Rocks!

This view from the Mast Camera (Mastcam) on NASA’s Curiosity Mars rover shows a site where two different types of bedrock meet on lower Mount Sharp. The rover is in a valley just below “Marias Pass.” The color has been approximately white-balanced to resemble how the scene would appear under daytime lighting conditions on Earth. The paler part of the outcrop, in the foreground, is mudstone similar to what Curiosity examined at “Pahrump Hills.” The darker, finely bedded bedrock higher in the image and overlying the mudstone stratigraphically is sandstone that the rover team calls the “Stimson” unit. The scene covers an area about 10 feet (3 meters) wide in the foreground. Courtesy: NASA/JPL-Caltech/MSSS

While we’re waiting for more news from New Horizons, I wandered over to the Mars Curiosity web site to look at what our intrepid rover has been doing since scientists regained communications with it. They didn’t have much contact with it when Mars was on the “other side” of the Sun during much of June, so the images slowed to a halt for a short time.

Curiosity is now exploring a region where the rocks are telling us a story about the environmental conditions on Mars in the distant past. The image here shows an area where two different rock types meet. One type is made up of light-colored mudstone, which indicates that the region was once under water that wasn’t moving very fast (if at all). The other type is a sandstone that appears to have been laid down in multiple layers as water moved across the surface.

What does that tell us about the long-term history of the planet? For now, it means that water once clearly existed in the region where Curiosity is studying the rocks. The mudstone was laid down by standing water, perhaps in a lake or a pond or a deep-ocean region. Mudstone is made of fine particles of rock that wafted to the bottom of the body of water and was allowed to rest before the water went away and the mud hardened to rock.

The sandstone is larger grained than the mud and silt, and it was likely carried along by a slow-moving current in a lake or sea, or by a quiet river. It had time to settle into layers and harden, so it’s unlikely that there were many catastrophic floods at the time the sandstone was laid down. If there had been floods, we’d see larger rocks embedded in the sand.

Rocks can tell us many stories about the environment, if we know how to read what they have to say. That’s the job of geology — to help us make sense of how the rocks were made, deposited, and perhaps carried along by water and wind.