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.
As incredible as it is to believe, NASA’s Opportunity rover is still going strong on Mars, nearly fourteen years after landing in January 2004. And now once again, it has just passed the shortest daylight time of the Martian year, the worst part of the Martian winter, with pretty clean solar panels to boot. Unlike the newer Curiosity rover which uses nuclear power, Opportunity, and its now-dead twin Spirit, uses solar panels for energy. At the same time, the rover continues to study an ancient gully thought to have been carved by water in the distant past.
Does Mars, or did it ever, have life? We still don’t know the answer to that question, but scientists have found new evidence that at least one region had ancient sea-floor hydrothermal activity, a discovery that increases the chances that microbial life may have once existed, and could also provide clues as to how life started on Earth.
The new findings are based on observations by NASA’s Mars Reconnaissance Orbiter (MRO) of a basin in the southern hemisphere called Eridania. The basin contains huge deposits which scientists think were formed by hot water which entered the bottom of a large sea about 3.7 billion years ago. The water was heated by volcanic activity, but today, the volcanoes are no longer active and the sea has long since evaporated.
“Even if we never find evidence that there’s been life on Mars, this site can tell us about the type of environment where life may have begun on Earth,” said Paul Niles of NASA’s Johnson Space Center in Houston. “Volcanic activity combined with standing water provided conditions that were likely similar to conditions that existed on Earth at about the same time – when early life was evolving here.”
This undersea hydrothermal activity would likely have been similar to what still occurs on Earth today, and at about the same time when life is thought to have started here. As such, this sea could have been a “cradle for life” on Mars.
“This site gives us a compelling story for a deep, long-lived sea and a deep-sea hydrothermal environment,” Niles said. “It is evocative of the deep-sea hydrothermal environments on Earth, similar to environments where life might be found on other worlds – life that doesn’t need a nice atmosphere or temperate surface, but just rocks, heat and water.”
There is still much debate as to whether Mars once had a larger ocean in the northern hemisphere, but even a smaller sea could have provided very habitable conditions. This sea is estimated to have contained 210,000 cubic kilometres (50,000 cubic miles) of water, nine times more than all of the Great Lakes on Earth. Minerals found in the deposits by MRO include serpentine, talc and carbonate.
“Ancient, deep-water hydrothermal deposits in Eridania basin represent a new category of astrobiological target on Mars,” according to the report. “Eridania seafloor deposits are not only of interest for Mars exploration, they represent a window into early Earth.”
There is also now evidence for current hydrothermal activity on the bottom of Enceladus’ global subsurface ocean, and perhaps Europa as well, which makes these moons prime targets in the search for life elsewhere in the Solar System.
The new hydrothermal findings add clue to the growing knowledge that Mars was once a very wet place, with rivers, lakes, deltas, seas, groundwater and hot springs.
This article was first published on AmericaSpace.
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.
NASA’s Opportunity rover has been busy examining the entranceway to Perseverance Valley, a long, shallow gully-like channel on the rim on Endeavour Crater which was likely created by flowing water millions or billions of years ago. This feature has been a major target of interest for mission scientists since, if confirmed, this would be the first such gully seen up close by any rover. A new panoramic image just released shows the view on the crater rim just above the valley itself, which includes a possible “spillway” where water once flowed over the rim and into the crater down below.