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.
Europa is one of the most fascinating places in the Solar System, and is considered to be at or near the top of the list of worlds to search for possible evidence of life. Beneath its outer ice crust lies a deep and dark salty ocean, thought to be quite to Earth’s own oceans. Could that ocean be inhabited, even if just by microbes? Scientists want to know, and now a new proposal calls for a joint orbiter/lander mission between NASA and ESA (European Space Agency), to try to answer that question.
Just recently, an exo-planetary system called TRAPPIST-1, with seven known planets close in size to Earth, was announced by astronomers. Some of those planets are in the star’s habitable zone, meaning that they could potentially be habitable for some kind of life. Then, another Earth-sized world was found orbiting the star GJ 1132b, and may have water and methane in its atmosphere. Now, another similar planet has been found orbiting another nearby star. It is also close in size to Earth and resides in the star’s habitable zone. According to scientists, it is another prime candidate in the search for alien life and may even be the best one yet.
There is an interesting new paper out about the seven near-Earth-sized exoplanets orbiting the star TRAPPIST-1. According to the study, four of the planets may be true water worlds, although just what form those may take isn’t clear. All seven planets are close in size to the Earth, with some of them in the star’s habitable zone, where temperatures could allow liquid water on rocky surfaces.
For those who are hoping to find evidence of life somewhere else in the Solar System, there was some exciting news this week. Two moons, Europa and Enceladus, were already thought to be among the best places to search, since both have liquid water oceans beneath their outer icy shells. And now, new data from the Cassini spacecraft and the Hubble Space Telescope has increased the potential for some form of living organisms to be found.