Curiosity Rover Discovers Clue in 'Rock Stripes' That Mars Has Its Own Water Cycle
As it approaches 5,000 Martian days on the Red Planet, the Opportunity has proven once again that wondrous discoveries can lurk anywhere, even in a bunch of gravel and sand: its recent exploration of Perseverance Valley has revealed that the slopes seem to have "rock stripes," which are generally formed by wet soil freezing and thawing here on Earth. These seemingly innocuous formations of gravel, sand, and soil may mean that the Red Planet still sees occasional snow and ice.
Opportunity's mission was originally intended to last only about 90 Martian days, but in the 14 years since it landed, the rover has lasted much longer than anyone expected, allowing NASA scientists to make several breakthrough discoveries about Mars, including discovering evidence of ancient water and geothermal vents. This complements the discoveries made by the younger Curiosity rover, which proved that the planet may have once supported life (and that the radiation on the surface is much more intense than expected). This new discovery from Opportunity proves that there's even more to learn. Like potentially discovering microbial alien life; after all, we've already proven life survives for millions of years on the Red Planet.
"Perseverance Valley is a special place, like having a new mission again after all these years. We already knew it was unlike any place any Mars rover has seen before, even if we don't yet know how it formed, and now we're seeing surfaces that look like stone stripes. It's mysterious. It's exciting," said Ray Arvidson, one of the scientists attached to the Opportunity mission.
The rock stripes could be formed by wind, or may be ancient enough that the processes that formed them are no longer happening, but the most exciting hypothesis is that Mars' poles are still dusting the planet with frozen water:
"Other lines of evidence have convinced Mars experts that, on a scale of hundreds of thousands of years, Mars goes through cycles when the tilt or obliquity of its axis increases so much that some of the water now frozen at the poles vaporizes into the atmosphere and then becomes snow or frost accumulating nearer the equator."
If this is the case, then Mars could be a lot more like Earth, with water playing a much larger role than previously thought. As far as extraterrestrial discoveries go, it's not bad for an old-timer like Opportunity.