How important is the presence of liquid water?
It is now widely believed that Mars holds a reasonably large amount of water.
However, the surface of the planet is so cold that this water exists only as ice.
For life to exist on a planet, many scientists believe that it is essential for the world to possess liquid water.
Ever since technology has allowed humanity to stare at Mars in detail, humans have been looking for indications that there was water on the red planet.
Did water float on the surface of Mars?
The Mariner 9 mission revealed traces of water erosion in river beds and ravines, as well as evidence of weather fronts and nebulae on Mars in 1971.
Later missions from Viking orbiters, first launched in 1975, revealed even more details about how water flowed on the surface and carved valleys.
Several studies have examined the presence of liquid water for decades. In 2000, the first evidence of liquid water on Mars was discovered.
It was claimed that the gorges seen on the surface of the planet should be formed by flowing water.
Scientists cited the remains and mud deposits left as evidence of moving water that existed at some point in the history of the red planet.
However, the formation of these gaps has been hotly debated in subsequent years.
Evidence of ice in geological samples from Mars
Spirit and Opportunity, the twin robbers, found evidence of the presence of water trapped in the rock in 2007 when one of Spirit’s wheels broke and put a piece of rock to pieces.
Analysis of the silica-rich layer detected in the scratch indicated that it was formed in the presence of liquid water.
In 2008, the Phoenix lander collected geological samples and they disappeared after a few days.
Scientists thought it was ice cubes. This assessment was confirmed when the lander later discovered water vapor in a sample.
In 2012, Curiosity meandered over an ancient ocean floor on Mars as it studied a series of rocks that were exposed to liquid water billions of years ago.
In 2012, Curiosity (pictured) meandered over an ancient ocean floor on Mars as it examined a series of rocks that were exposed to liquid water billions of years ago
Recurring sloping lines and debate cause it
Features known as recurring slope lineae (RSL) were first identified in 2011.
These dark stripes populate the areas of Mars with a sharp slope.
Scientists speculated that these may be caused by the intermittent flow of liquid water down the steep shores of the planet.
In June 2013, Curiosity found strong evidence that water good enough to drink once flowed on Mars. In September of that year, the first scoop of soil analyzed by Curiosity revealed that fine materials on the planet’s surface contain two weight percent water.
In 2015, Nasa claimed to have discovered the first evidence of liquid water on Mars today.
The space agency said its Mars Reconnaissance Orbiter (MRO) provided the strongest evidence yet that liquid water is flowing intermittently on today’s Mars.
In 2017, Nasa issued yet another statement reprimanding its initial findings.
Features known as recurring slope lineae (RSL) were first identified in 2011 (pictured). These dark stripes populate the areas of Mars with a sharp slope. Researchers wondered if these could be caused by the intermittent flow of liquid water
It said that the dark features that run down steep climbs on the red planet were actually granular streams where sand grains and dust grains slide downhill to make dark streaks, instead of the ground being darkened by seeping water.
Pictures from the MRO revealed that the streaks only exist on slopes that are steep enough for dry grains to fall down, as they do on faces of active dunes.
Also in 2017, scientists provided the best estimates for water on Mars, claiming that it once had more liquid H2O than the Arctic Ocean – and the planet held these oceans for more than 1.5 billion years.
The results suggest that there was plenty of time and water for life on Mars to thrive, but over the last 3.7 billion years, the red planet has lost 87 percent of its water – leaving the surface barren and dry.
An underground lake
In a study published in the journal Science, ESO scientists have now discovered the first concrete evidence of liquid water on Mars.
Using radar images from the Mars Express probe, the ESO team has found a 12-mile-long underground lake filled with liquid water.
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