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?
The Curiosity rover has now resumed its journey toward Mount Sharp after experiencing some delays due to a faulty drill mechanism. The rover conducted a short drive over the past weekend toward a new location with “plenty of science targets to choose from.” Being on the road again is of course a relief to mission engineers and scientists, although the problems with the drill are still being diagnosed. As has come to be expected, Curiosity again made some exciting science observations in 2016, which continue to show that this region on Mars was once a lot more habitable in the ancient past, and perhaps bringing us closer to answering the question of whether life ever actually did exist there.
NASA held another press briefing this week about the latest findings from the Curiosity rover on Mars, detailing new evidence that this former lake environment was once quite hospitable for possible life. The findings were announced from the fall meeting of the American Geophysical Union in San Francisco. In a related development, there is also new evidence from Curiosity that organics have not only been definitively found by the rover, but that they may be more widespread on Mars than previously thought.
Ever since first landing in August 2012, the Curiosity rover has helped to revolutionize our understanding of Mars and has seen some incredible scenery along the way. It has travelled across an ancient lakebed and gazed at towering sand dunes and buttes, and now it is ready to begin the next phase in its mission: gradually ascending the lower slopes of Mount Sharp, the massive mountain sitting in the middle of Gale crater. The layers in the mountain will provide more clues as to how the Martian environment changed from being much wetter than it is now, to the dry but cold desert we see today. This next chapter in the rover’s mission is part of a two-year extension which began Oct. 1, 2016.
Mars has often been compared to deserts on Earth, and for good reason: it is pretty much a barren landscape with a lot of sand and rocks everywhere. Sometimes, the similarities can be quite striking, and the terrain in Gale crater where the Curiosity rover is roaming around is a good example. The rover is currently in a region of stunning scenery – buttes and mesas which are very reminiscent of ones on Earth. This area could easily be mistaken for the American southwest if it weren’t for the dusty, pinkish sky and complete lack of vegetation. Curiosity is now getting a close-up look at these formations, which are not only beautiful but record a long and fascinating geological history.