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rsl

Nosotros used to think of Mars as a dry, desolate planet devoid of running h2o. Then, in 2022 astronomers discovered testify that liquid water might notwithstanding flow on the Martian surface. This gave scientists hope that life may still exist on the red planet and that humans could more than easily prepare up camp there. However, new prove suggests past observations might not have been water at all. The dark streaks on Mars could simply exist more sand.

Scientists refer to the mysterious dark streaks on Mars every bit recurring slope lineae, or RSL. They behave like you'd expect water to comport: in the warm season, the dark streaks announced by the thousands on steep slopes. They get longer and darker, until they abruptly vanish every bit winter takes concord. The leading hypothesis stated that brine (water with high salt content) locked up in the soil would run down the slopes each spring, then recede in the winter.

A new analysis of RSL has been published in Nature Geoscience, conducted by a squad from the U.s.a. Geological Survey, the Planetary Science Institute, the University of Arizona, and the Britain's Durham University. The team used data from the Mars Reconnaissance Orbiter (below), a satellite that has been observing Mars from more than than 200 miles above for the last decade. The satellite was used to written report 151 RSLs at x unlike sites, and the researchers noticed a foreign trend. All the streaks ended at similar points, no matter the length of the gradient. If this was seeping water, the streaks should be longer on longer slopes.

The team says RSL compare more accurately to granular flows here on Earth — Martian soil that'southward sliding down the slopes. This would involve petty or no liquid water in the RSL. The presence of hydrated salts on Mars could play a office, though. These molecules can pull water vapor out of the thin atmosphere, which could cause the darkening and trigger an RSL without "flowing" water.

Whatever the cause, the study notes that nosotros won't know until an RSL can be investigated kickoff-hand. Globe is the only analog to Mars nosotros accept, and at that place are too many differences to test our current hypotheses hither. Even if a future rover determines there'due south no flowing water in RSLs, we do know there's enough of water on Mars in the class of water ice at extreme latitudes. There are also other signs that liquid h2o could exist in other areas.