September 29, 2015

Liquid Water On Mars: All the Facts

NASA has shared some strong facts and evidence that liquid water flows intermittently on present-day Mars. Using an imaging spectrometer on NASA's Mars Reconnaissance Orbiter (MRO), researchers detected signatures of hydrated minerals on slopes where mysterious streaks are seen on the Red Planet. The detection of hydrated salts on these slopes means that water plays a vital role in the formation of these streaks. Here in in this post we take a look at some of the facts NASA shared as evidence.




The Darkish Streaks (RSLs)
The darkish streaks appear to ebb and flow over time. They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons. They appear in several locations on Mars when temperatures are above minus 10 degrees Fahrenheit (minus 23 Celsius), and disappear at colder times. These downhill flows, known as recurring slope lineae (RSL), often have been described as possibly related to liquid water.

The Hydrated Salts (Percholates)
Spectrometer observations show signatures of hydrated salts at multiple RSL locations. Spectral signatures are believed to be caused by hydrated minerals called perchlorates. The hydrated salts most consistent with the chemical signatures are likely a mixture of magnesium perchlorate, magnesium chlorate and sodium perchlorate. Some perchlorates have been shown to keep liquids from freezing even when conditions are as cold as minus 94 degrees Fahrenheit (minus 70 Celsius). On Earth, naturally produced perchlorates are concentrated in deserts, and some types of perchlorates can be used as rocket propellant.

Relationship between dark streaks & the hydrated salts
The new findings of hydrated salts on the slopes point to what that relationship may be to these dark features. The hydrated salts would lower the freezing point of a liquid brine, just as salt on roads here on Earth causes ice and snow to melt more rapidly. The detection of hydrated salts on these slopes means that water plays a vital role in the formation of these streaks

These dark, narrow, 100 meter-long streaks called recurring slope lineae flowing downhill on Mars are inferred to have been formed by contemporary flowing water. (Image Source: NASA)

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