In September last year, NASA announced that it found evidence that liquid water flows on the surface of planet Mars.

Hydrated Salts In RSL Sites

Scientists took cue from recurring slope lineae (RSL), darks streaks that seasonally appear and vanish on steep slopes on the surface of the Red Planet. Data from the Mars Reconnaissance Orbiter indicated the presence of hydrated salts in RSL sites, which was initially speculated as sign of flowing liquid water.

The discovery of the hydrated salt and the idea of the arid planet having flowing liquid water today generated excitement because these suggest of the possibility that Mars may be capable of supporting alien life.

The U.S. space agency has been sending missions to planet Mars in the hopes of findings signs of past or present life. The presence of liquid water would also be helpful in future manned missions to the Red Planet. The plan to visit Earth's neighboring planet isn't just for astronauts. In September this year, SpaceX CEO Elon Musk also unveiled the plans of his company to bring humans to Mars.

RSL Salts May Have Come From Mars' Atmosphere

Findings of a new study, however, may extinguish some of the excitement of flowing water on Mars.

It is possible that the water that the RSL salts have originated from the planet's atmosphere and not from liquid water at or near the surface of the planet so researchers conducted experiments to probe into this.

Raina Gough and Margaret Tolbert, both from the University of Colorado, Boulder, exposed anhydrous (dry) salts to atmospheric conditions comparable to that of Mars and discovered that some of these salts, which include calcium chloride and calcium perchlorate, became hydrated. Interestingly, the RSL salts detected on Mars are a kind of perchlorates as reported by the researchers who found them.

"The hydrated salts most consistent with the chemical signatures are likely a mixture of magnesium perchlorate, magnesium chlorate and sodium perchlorate," NASA has said. "This study of RSL detected perchlorates, now in hydrated form, in different areas than those explored by the landers. This also is the first time perchlorates have been identified from orbit."

It is still possible that liquid water indeed plays a part in the formation of hydrated salts within the RSL sites on Mars. The findings, however, raised concerns that need to be addressed and investigated through future experiments.

"Hydrated salts are not always evidence of liquid water," Gough said.

The findings were presented at the American Geophysical Union meeting on Dec. 13.

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