After years of speculation, scientists have confirmed the discovery of salty liquid water on the surface of Mars.
It's widely believed that large oceans once covered the surface of the red planet, but recent observations have now shown that liquid water still exists on the planet today. Liquid water is essential to supporting life — at least life as we know it — so the implications of this discovery are enormous. The salt content of the water drastically reduces the freezing point, which is part of what makes it possible for it to exist as a liquid on the cold surface of Mars. Water in its frozen and gaseous states on Mars have been known for quite some time.
The full report has been published in Nature Geoscience.
"Our quest on Mars has been to 'follow the water,' in our search for life in the universe, and now we have convincing science that validates what we've long suspected," NASA's John Grunsfeld noted in a statement. "This is a significant development, as it appears to confirm that water—albeit briny—is flowing today on the surface of Mars."
Each spring, when temperatures begin to increase, dark streaks appear on the martian surface. Later in the year when things become cold again, they disappear. These seasonal formations were dubbed recurring slope linae (RSL), but it wasn't initially obvious what they were made of. Thanks to observations by the Mars Reconnaissance Orbiter and clever deduction by scientists, they have found that these features are hydrated salts.
It still isn't known exactly where the water is coming from. There aren't obvious features on the surface, so the current most likely candidate is that it is coming from underground. However, an ordinary underground aquifer still leaves too many questions unanswered.
This will likely be cleared up with further investigation, as will the possibility of potential life on the planet.
"It took multiple spacecraft over several years to solve this mystery, and now we know there is liquid water on the surface of this cold, desert planet," Michael Meyer of NASA's Mars Exploration Program explained in the statement. "It seems that the more we study Mars, the more we learn how life could be supported and where there are resources to support life in the future."
Though the salt content of the water is high, scientists are still hopeful that it could lead to the discovery of microbial life on Mars. After all, there are many organisms on Earth that thrive in a variety of extreme conditions.
Scientists are now setting their sights on collecting samples in regions most likely to harbor life. However, this has to be done extremely carefully. Though spacecraft are cleaned very carefully before launch, there is a very real possibility that microbes could persist on the equipment and contaminate samples.
Much still remains to be learned about this martian water, including how it could potentially be utilized by human astronauts seeking to explore Mars in the future. This discovery is only the beginning.
[All images via: NASA/JPL/University of Arizona]