The planet Mars has many similar features to Earth, but one unique feature stands out given the abundance of craters across the Martian surface known as recurring slope lineae (RSL), which are dark streaks that have been observed to occur within craters and have been previously attributed to extra salty water, also called brines. Now, a team of researchers challenges these longstanding notions while proposing another hypothesis for the creation of RSL. This study, which was published in Nature Communications, has the potential to help researchers better understand the current processes on Mars, which consist of the water cycle, dust cycle, and carbon cycle.
For the study, the researchers used machine learning algorithms to analyze a global map of RSL candidates ranging from approximately 600,000 to almost 2.5 million, depending on the confidence level of the algorithms. The goal of the study was to ascertain the processes responsible for creating RSL, whether it’s from brines another geological process. In the end, the researchers found that dust is responsible for creating RSL, as they estimate that less than 0.1 percent of the Martian surface is modified from RSL, they are still responsible for transporting the equivalent of several global dust storms annually, meaning they greatly influence the Martian dust cycle.
Image of dark streaks obtained by the CaSSIS camera aboard European Space Agency (ESA) ExoMars Trace Gas Orbiter, (Credit: NASA)
“A big focus of Mars research is understanding modern-day processes on Mars — including the possibility of liquid water on the surface,” said Dr. Adomas Valantinas, who is a postdoctoral researcher at Brown University and co-author on the study. “Our study reviewed these features but found no evidence of water. Our model favors dry formation processes.”
Going forward, this study could help alleviate concerns about contaminating potential lifeforms in brines with Earth microbes during future space exploration missions to Mars, also called planetary protection. Additionally, this could open doors for expanding Mars exploration opportunities while still searching for potential signs of past or present life.
What new discoveries about RSL will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: Nature Communications, EurekAlert!
