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.
For about the past 30 months, the Opportunity rover has been exploring Cape Tribulation on Mars, a towering ridge on the rim of Endeavour crater. Now, Opportunity has finally left that location, to continue its journey southward down the western side of the crater rim. The views have been scenic from the top of Cape Tribulation, but now it is time to move on, and head to the next major target, an ancient gully not too far to the south-east, also on the crater rim. This gully is thought to have been carved by running water millions or billions of years ago, so scientists are very interested in examining it up close, and the rover is now almost there.
With thousands of images taken by various probes sent to Mars, it would seem inevitable that unusual or puzzling objects might be seen in some of them. And of course, there have been, most notably the famous “Face on Mars” first seen in low-resolution Viking orbiter images in the 1970s. Higher-resolution images taken later by other orbiters with better cameras showed it, and nearby interesting formations, to be just natural hills and mesas. Despite that, other curious things are seen in both orbital and ground images from time to time, although they almost always have a simple prosaic explanation. Another such oddity was just recently seen in an image taken by the Mars Reconnaissance Orbiter (MRO), which has attracted some attention. Most likely it is a natural rock formation, but it’s also not, as described by the tabloid Daily Mail, a “spherule” either.
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.