As we enter 2018, NASA’s Curiosity rover continues to be busy exploring on top of Vera Rubin Ridge, on the lower flanks of Mount Sharp. The rover is gradually making its way farther up the flanks, closing in the picturesque foothills in front of it. As it does so, Curiosity has made two new interesting discoveries, which may have implications for the possibility of life.
NASA’s Curiosity rover has found even more evidence for a previously habitable environment in Gale crater on Mars, according to a new study just published. The findings point to a history of hydrothermal activity in the region, which combined with other evidence for a past lake in the crater, makes an even more compelling case for possible ancient life.
The study has been published in the Journal of Geophysical Research: Planets, a journal of the American Geophysical Union. According to Jeff Berger, lead author and a geologist at the University of Guelph, Ontario, the rover found concentrations of zinc and germanium 10 to 100 times greater in sedimentary rocks in the crater as compared to typical Martian crust.
On Earth, these elements tend to be enriched together in hydrothermal environments with hot water and sulfur, and these environments are teeming with a wide array of microbial life. Hydrothermal deposits are also ideal for preserving fossilized remains of such life.
“You have heat and chemical gradients… conditions favorable for the genesis and persistence life,” Berger said.
The researchers used data from Curiosity’s APXS instruments to measure 16 major, minor and trace elements in the rocks at Gale Crater, including zinc. They also used the Chemistry and Mineralogy instrument to analyze samples from the drill and scoop. It wasn’t expected that germanium would be found, since the estimated abundance of it would be below the detection limit if the APXS. But they did find it, at concentrations up to 100 times more than in a typical Martian meteorite. In one mineral vein examined, it was almost 300 times more. Usually, there is a standard germanium-silicon ratio in Martian rocks, but this was not the case in the rocks studied from Gale crater.
Evidence for past hydrothermal activity, such as hot springs, had also been previously discovered by the Spirit rover in Gusev crater. Spirit even found unusual nodal formations composed of silica resembling “cauliflower,” similar to ones seen in hydrothermal environments on Earth. Later studies have even suggested that they are reminiscent of ones on Earth known to have been created by microbes. Not enough is known yet about these formations to determine if life was actually involved, and Spirit unfortunately died in 2010 after becoming stuck in sand near some of these silica deposits.
According to Curiosity mission project scientist Ashwin Vasavada, the additional evidence for hydrothermal environments in Mars’ past implies the existence of a “whole variety of conditions that might all fall under the umbrella of being habitable.”
More information about the Curiosity mission is available here.
This article was first published on AmericaSpace.
Was Mars ever habitable? Did life ever actually exist there? Those are two of the biggest questions for planetary scientists and slowly but surely, we are getting closer to answering them. Well, the first one has been, thanks to the numerous orbiters, landers and rovers which have been sent to the Red Planet over the past few decades. Mars was indeed much more habitable than it is now, in the distant past, although we still don’t know if it was actually inhabited, two different things. Much of the data confirming past habitability has come from the Curiosity rover, which has been exploring an ancient lakebed in Gale crater, and now new findings suggest that this lake offered multiple types of microbe-friendly environments simultaneously. This is good news for the possibility that some form of life, even if just microscopic, did once exist there or perhaps even still does.
As the Curiosity rover continues its traverse among the buttes and sand dunes of Gale crater, you would expect to see some wear and tear after a few years. The rover’s wheels have naturally taken the brunt of that, with small dents and holes appearing in the solid aluminum. But now, new damage has been seen for the first time, breaks in the raised treads on the wheels, called grousers. While not unexpected, and not a mission-stopper by any means, it does show how the wheels, and the rover overall, have been aging since landing in 2012.
The subject of water on Mars is one of the most highly debated in planetary science; various missions have provided ample evidence that the planet used to be a lot wetter than it is now, with rivers, lakes and maybe even oceans. Most scientists now generally agree on this, but as to how much water there was, how long it lasted and how warm the environment was, is another question. There have been apparent conflicting lines of evidence, and now findings from the Curiosity rover have only added to the mystery. Curiosity has revealed a paradox of sorts – it has found abundant evidence for ancient lakes in now-dry Gale crater, but at the same time has not found evidence for a previous thicker atmosphere with more carbon dioxide, which normally would be needed for water to remain liquid on the surface. These two lines of evidence seem to contradict each other, so how to resolve this puzzle?