If you listen carefully, you can hear the sound of space nerds everywhere jumping up and down and shrieking with excitement because scientists just announced that we’ve found a giant lake on Mars!
We’ve always known that there’s been water on Mars, but the only proof we’ve had up until today has either come from seasonal lakes or evidence that water used to flow on Mars way back when it had warmer temperatures and a thicker atmosphere. It’s thought to be around -68 Celsius (-90 Fahrenheit) over there, and for liquid water to exist, it must be full of salts that lower its melting point - so much salt that it’s more like brine than water. We’ve never found a permanent body of water on Mars, or anything close to this much of it in one place.
But thanks to the European radar instrument MARSIS, we now know with absolute certainty that a giant underground lake is currently existing on Mars in the present day.
MARSIS uses radar technology to look below the surface of Mars, similarly to the radar we use to detect planes here on Earth. By sending out radio waves and measuring how they bounce back, we grasp an idea of what’s out there. We are also able to derive some properties of what those waves pass through and bounce off of, which is how the scientists made their discovery when they analyzed three years worth of data on Mars’s south pole.
It’s covered in a layer of mostly water ice, but about two kilometers (one mile) below the surface, the waves reflected off something weirdly bright, shiny, and big. As it turns out, that distinction happened to be the boundary between ice and liquid water.
The researchers looked into a few other possibilities like whether it was a layer of frozen carbon dioxide, but when they ran the numbers, liquid water was the only case that made any sense. The lake on Mars stretches across an area about twenty kilometers (twelve miles) wide, and is either in a separate layer or mixed with some sediment in what’s possibly the most exciting sludge humanity has ever found.
What makes this even cooler is that if water exists on Mars, that also indicates the huge possibility that life also exists or may have existed in the body of water.
Liquid water is essential for life as we know it, which is why practically all of our search for life on other worlds revolves around water. The problem is that the water would be an extremely harsh environment for life to thrive; it’s full of salts and extremely cold.
Another problem is the chemical composition of the salts dissolved in the lake. We aren’t talking about table salt here - we’re talking about perchlorates, which are compounds toxic to humans and basically more intense than bleach.
Martian soil is full of them. So if you ever get the chance to visit Mars’s underground lake, do not lick it!
Some especially tough microbes like tardigrades and extremophiles can technically live in environments like this. They can go decades without any water, survive in a vacuum, and even feed off perchlorates. Additionally, the water may be warmer and less salty than we think. But even for them, this would be cutting it pretty close.
So basically, humanity has accomplished one more historically groundbreaking achievement and determined another fantastic place to search for life on Mars. But of course, sending a mission to Mars to look for life deep below the surface is easier said than done - just not impossible!
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Sources: This story was originally published on SciShow.
I am republishing a lightly edited version on SkyFeed in light of interest in the subject.
Green, Hank. "A Giant Underground Lake on Mars!" SciShow, YouTube. 25 July 2018. Web video.
Halton, Mary. "Liquid Water Lake Revealed on Mars." BBC News. 25 July 2018. Web article.
Citation: Rovira, Lia N. "New Evidence Proves There's an Existing Lake on Mars." SkyFeed. 1 Aug, 2018. Web article.