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.
Last week there was the exciting news that Mars still has flows of briny water occurring now, and this week there is more water-related news: additional findings from the Curiosity rover that the huge Gale crater was once a lake or series of lakes a long time ago. Curiosity had already found evidence that there used to be shallow lakes and streams in this area, but the new data confirms this and suggests that the lake(s) once filled Gale crater and were long-lasting, explaining the formation of Mount Sharp in the middle of the crater and also providing a potentially habitable environment for life.
The Curiosity rover, still roaming in Gale crater, has discovered the first evidence for a potential ancient “continental crust” on Mars, which would be a very significant finding regarding Mars’ early history and to what degree it may have paralleled Earth’s.
As the Curiosity rover currently inspects a rock outcrop called Cooperstown, this rock seems to be baring its teeth. Some interesting pointed protrusions can be seen near the middle and lower right of the image. Below is a closeup of one of these teeth-like protrusions. Fossilized Martian shark teeth? No, probably not, but they are an intriguing feature for sure.
This is an interesting rock seen recently by the Curiosity rover on sol 402 (left navigation camera) while making its way toward Mount Sharp in Gale crater. A seat for the weary Martian traveller? 🙂
For any future astronauts who land on Mars, there is one piece of advice that shouldn’t even need to be said: keep your helmet on! Mars has an atmosphere, like Earth, but it is much thinner than ours (and mostly carbon dioxide), and so is unbreathable by humans. However, evidence has continued to grow that Mars’ atmosphere was once a lot thicker than it is now, early on in the planet’s history. Recent findings from the Curiosity rover have added to that evidence, as well as showing not only how Mars has lost most of the atmosphere that it once had, but also that the atmosphere which remains is still very active.