Mars is covered with spooky little grooves, some of which have been attributed to flowing water. Unfortunately, it seems scientists might have been a little off in their understanding of some of Mars’s lines — and it’s potentially a bummer for astrobiologists.

Historically, seasonal dark streaks on the Red Planet have been the source of some debate. Some scientists have suggested that these lines — called recurring slope lineae (RSL) — were caused by once-flowing water on the planet. Others have posited the grooves were created by the flow of something else, such as sand.

But a new study published Monday in Nature Geoscience bolsters the latter idea — that flowing sand and dust from avalanches could have created these dark streaks.

“The RSL (recurring slope lineae) on Mars behave in a similar way to laboratory experiments on Earth,” Planetary Science Institute Senior Scientist Jim McElwaine, a co-author on the paper, said in a statement. “What is still not understood is where the supply of fresh material comes from, though we do have some speculative ideas.”

If Mars’s RSL are indeed formed by sand — not water — that could be a sign that the Red Planet has been dry for a really long time. That doesn’t bode well for astrobiologists and other scientists hoping to find microbes on Mars.

Of course, we have a lot more searching to do before we know what the RSL are for sure. Hopefully we still find tiny traces of life no matter what.


Photos via NASA/JPL, NASA/JPL/University of Arizona