Back in the 1970s, NASA’s Viking mission identified – among many other fascinating things – some curious dark streaks following downward slopes on Mars’s surface.

Though we have yet to discover what those streaks actually were, some scientists purported that they could be running water on the Red Planet’s surface, leading to widespread hope that our neighboring planet could share some habitable conditions with Earth.

In the time since, scientists have debated what these dark streaks could actually be; now with international space programs targeting people on Mars in the near future, the possibility of surface water seems more pressing than ever.

However, a new study from planetary scientists at Brown University and the University of Bern, Switzerland, has dashed hopes with the revelation that these dark streaks are unlikely to be running water after all.

Their research, which has been recently published in the journal Nature Communications, used machine learning to recreate the dark streaks and fully understand them.

But their results – which suggested that rather than water, they are more likely evidence of dust falling down some of Mars’s steep slopes – will be disappointing to some, as Brown’s Adomas Valantinas explained in a statement:

“A big focus of Mars research is understanding modern-day processes on Mars — including the possibility of liquid water on the surface. Our study reviewed these features but found no evidence of water. Our model favors dry formation processes.”

To reach their conclusions, Valantinas and Bern colleague Valentin Bickel used algorithms to scan 86,000 satellite images of these slope streaks on the Red Planet, concluding in a catalogue of over 500,000 slope streaks in total. This catalogue helped them to truly understand these mysterious formations, as Bickel continued:

“Once we had this global map, we could compare it to databases and catalogs of other things like temperature, wind speed, hydration, rock slide activity and other factors Then we could look for correlations over hundreds of thousands of cases to better understand the conditions under which these features form.”

With this information in mind, the team were able to conclude that contrary to previous suggestions, these sloped areas are unlikely to be suitable for human habitation, saving space programs considerable time and money in research, as Valantinas noted:

“That’s the advantage of this big data approach. It helps us to rule out some hypotheses from orbit before we send spacecraft to explore.”

Though the researchers have ruled out liquid water falling down those slopes, their data does give the space science community considerably more information about the terrain and environment on Mars, since these slope streaks are likely to only form in windy and dusty places.

They note that they are also common near craters, telling us even more about how Mars’s surface reacts to things like meteor strikes and potential seismic activity – all important factors if people are to live on the planet one day.

It might not be the answer we were hoping for, but its interesting nonetheless.

If you thought that was interesting, you might like to read about a quantum computer simulation that has “reversed time” and physics may never be the same.