Liquid Water and Mars

We have long known that there was once water on Mars – the real question was whether liquid water still exists on the Red Planet, or whether it long ago dissipated into space.

This week, using instruments from theMars Reconnaissance Orbiter (MRO), NASA confirmed that there is strong evidence that there is still liquid water on Mars. The evidence can actually be seen in the image below as the dark streaks (called lineae) on the slopes of Hale Crater. These streaks are seasonal, they are darker and more prevalent in the warmer seasons, and recede in the cooler seasons – exactly what you would expect of liquid water.


Here is an nice flyby animation of these same sites:

Similar lineae have been observed on a number of other craters on Mars.

While this is water – it is not in the form that most people would easily recognize. It is water that is bound to salts and minerals forming a compound called perchlorate. Since this water is bound to the perchlorate, it may not freeze in the cold Martian atmosphere, and instead exist as a think brine.

Here is a really great video from the folks at SciShow:

So why then is the discovery of liquid water on Mars so important? After all, recent discoveries have indicated that there is water on comets and the moons of Jupiter and Saturn, so why is this such a big deal?

It all comes down to the search for life in the solar system. As you can see from our video below, the chemical properties of water have a special relationship with life.

While there is life in other locations in the solar system – these places are either too far away (planets and moons) or the water is definitely in a frozen state (comets). But Mars is close, and a number of countries, including the US,  have a host of missions either currently at the planet, or soon to be on their way. There are even plans to send humans to Mars in the next few decades.

Now that water has been identified, NASA has a focal point for their search for the chemical signatures of life, or at least the building blocks of life. The search for life has just entered an entirely new, exciting phase, and the next few years should change our perception of our place in the Universe.

Additional Resources

Image Credits

  • Mars image: NASA/JPL/University of Arizona
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