Everything we’ve observed so far about the surface of Mars points to an ancient past that was warmer, wetter, and very possibly habitable for life as we know it. From the scars of enormous floods and vast branching river deltas that are etched into the Martian surface to the rounded pebbles of ancient stream beds to the chemical signatures of materials formed only in the presence of water, the evidence for Mars’ wet history seems overwhelming. But there’s one big question that still stymies scientists: what happened to all of Mars’ carbon dioxide?
Even though Mars’ atmosphere is 96% CO2 today, it is incredibly thin—only 1% as dense as Earth’s. It’s thought that Mars once had a much thicker atmosphere in its early history, but was there enough of the greenhouse gas even then to keep it warm enough (with a cooler young Sun) to maintain liquid water on its surface? According to a new analysis of data from NASA’s Curiosity rover, Mars just didn’t have enough carbon dioxide 3.5 billion years ago to provide enough warming to prevent water from freezing solid.
“We’ve been particularly struck with the absence of carbonate minerals in sedimentary rock the rover has examined,” said Thomas Bristow of NASA’s Ames Research Center. “It would be really hard to get liquid water even if there were a hundred times more carbon dioxide in the atmosphere than what the mineral evidence in the rock tells us.”
But with all the physical evidence pointing at liquid water—even without the CO2—could something else have been keeping Mars warm?
Read the full story from NASA here: NASA’s Curiosity Rover Sharpens Paradox of Ancient Mars
I’m in a debunking mood today, probably brought on by the seasonal “double Moon hoax” that raises its oh-so-wrong head every August. (Read more on that nonsense here.) So here’s one more thing to say “NO” to: giant alien cave crabs on Mars.
Apparently there’d been some buzz recently in the “space woo” circles online over an image acquired by NASA’s Curiosity rover showing an exposed rock outcrop on Mars. In the image, tucked into a corner between a couple of larger rocks, is an oddly-shaped… thing… that some of the more “open-minded” (sarcasm intended) viewers have claimed is an alien organism, not unlike some that have made appearances in various sci-fi films over the years.
I’ve included the original Mastcam image above with the object in question outlined and “enhanced” on the left. Is this indisputable evidence of tentacled cave dwellers on the Red Planet? Hardly.
Do you love to look up at the Moon? Well so does NASA’s Curiosity rover! Feel free to correct me if I’m wrong (I have not confirmed this) but this appears to be an image of Phobos, the larger of Mars’ two small moons, imaged by Curiosity’s Mastcam on mission Sol 1002 (June 1, 2015). I spotted it while looking though some raw images on JPL’s MSL mission page.
Phobos is a very small world, only about 16 miles (26 km) across, and orbits Mars at 5,840 miles (9,400 km) altitude. Curiosity has imaged it before, once actually crossing in front of the Sun during an eclipse event on Aug. 20, 2013.
Both Phobos and its smaller, more distant sibling Deimos have been imaged together by Curiosity as well, during an occultation on Aug. 1, 2013. See an animation of those observations here.
Planned observations of Phobos help scientists more precisely determine its orbit.
See a color image of Phobos acquired by the HiRISE camera aboard Mars Reconnaissance Orbiter here.
The image above shows Curiosity’s view southwest into “Marias Pass,” a low valley in Gale Crater where the rover was on May 22, 2015 – mission Sol 992. At the left (east) edge is the western slope of a rise called Akipuni Mountain, and Mount Shields rises off to the right (west). The image is a mosaic made from four Mastcam images – click to view it full-size on Flickr.
The site is a bit of a backtrack from its previous location at Logan Pass, since the rover has been experiencing some slipping on the loose surface material in the area.
“Mars can be very deceptive,” said Chris Roumeliotis, Curiosity’s lead rover driver at NASA’s Jet Propulsion Laboratory, Pasadena, California. “We knew that polygonal sand ripples have caused Curiosity a lot of drive slip in the past, but there appeared to be terrain with rockier, more consolidated characteristics directly adjacent to these ripples. So we drove around the sand ripples onto what we expected to be firmer terrain that would give Curiosity better traction. Unfortunately, this terrain turned out to be unconsolidated material too, which definitely surprised us and Curiosity.”
Image credit: NASA/JPL-Caltech/MSSS. Edited by Jason Major.
Cold as hell and no place to raise your kids, the surface of Mars today is a quite inhospitable place for any forms of life we know of. But that wasn’t always the case – billions of years ago Mars may have been a lot more like Earth, with a magnetic field, a much denser atmosphere, lakes and even an ocean on its surface where life could have not just developed but thrived. And in Curiosity’s hunt for any remaining evidence of that ancient utopia, the rover has identified a key ingredient: nitrates contained within the surface rocks of Gale Crater.
Although it’s not thought that the nitrates were created by organisms currently living on Mars it’s yet another indication that the environment of Gale Crater was once a place where life could have existed, joining the rover’s previous discoveries of traces of water and sediment deposited by ancient rivers.
“Finding a biochemically accessible form of nitrogen is more support for the ancient Martian environment at Gale Crater being habitable,” said Jennifer Stern of NASA’s Goddard Space Flight Center, lead author of the research team.
Here’s a “selfie” of NASA’s Curiosity rover, made from about 20 images acquired by its MAHLI instrument on mission sol 868 (January 14, 2015). I used Photoshop to stitch the raw images together and then enhanced the contrast and detail with a bit of HDR effect. (There’s one spot behind the rover’s RTG where an image wasn’t available.)
How did Curiosity take this image (well, these images) you ask?