Is There Water On Mars?
On September 28, 2015, NASA scientists announced there is currently liquid water flowing on the surface of Mars. This opens the door to a myriad of other questions and thoughts. We’ve yet to send humans to the red planet nor do we have tangible proof of liquid water, so how do we know there is water on Mars? Listen to this Question Your World radio report produced by the Science Museum of Virginia to find out.
One of the grandest questions humanity has ever asked involves our place in the universe. Are we alone? Answering this massive question involves a lot of factors. Humanity has only touched two places in our solar system and they both are in the same planetary system. We’ve sent a few robots to some other places, but we’re still very new to advanced space exploration. The only way we can make guesses on the big question is by looking at what we have here. We know what it takes for life to exist here and so we look for similar situations elsewhere in hopes to get a little closer to answering that question. On Monday September 28, 2015, NASA scientists gave us a slight, but very important update on this search.
Early Egyptian and Chinese astronomers began studying Mars as early as 1000 BCE. The Greeks and Babylonians would also observe the tiny red dot in the sky for centuries. Then in 1610 we would finally have a major advance in Mars observation when Galileo Galilei pointed his telescope at our celestial neighbor. This is when we truly started to understand many of Mars’ physical characteristics like polar ice caps, ridges, valleys, its tilt, and so on.
As telescopes were improved upon so was our knowledge of the distant world. In the 1800’s the notion of Mars potentially holding life became a popular thought. Newly mapped canals and geographic landmarks filled the public’s imagination and fueled the interest for further research. As the rocket era advanced the notions of sending machines to Mars started to become a reality. Then in 1964 Mariner 4 made the first successful flyby of the planet, bringing us the first ever pictures of the surface. This mission would mark the first of many to follow which would help NASA scientists gain a more complete picture of the neighboring planet. Since then humanity has sent several orbiters, rovers, conducted surveys from Earth, the ISS, and various theoretical studies as well.
Currently, we have a very robust history of Mars thanks to robotic, telescopic, and computer generated exploration. All of these are necessary to explain how scientists now know there is liquid water flowing on the surface of that planet. Spectroscopy tools help identify the chemical finger prints of various elements, robotic sampling allows us to understand how some of the Martian terrain formed, visual evidence shows seasonal changing dark streaks (Reoccurring Sloping Lineae), samples from previous robotic missions support the theories on the formation of geologic features, and so on. There is no one quick answer here, but by taking all the evidence and putting it together scientists are able to narrow the options down to just one culprit, flowing salty water...sometimes.
Scientists announced that water only occasionally flows on the surface of Mars because this is a seasonal phenomenon. During the Martian spring and summer the reoccurring sloping lineae (RSL) advance and then disappear until the following spring. The study of the chemical signals detected here also support the theory that water is shaping these landscapes. Various chemical processes are needed to make the Martian surface the way it is at the RSL sites, but these processes would need to involve liquid water. Furthermore, many robotic missions in the past have also studied the atmosphere and soil in great detail only to conclude that without water many of these situations would not be possible. By taking all of this evidence and putting the pieces together scientists have now concluded that the red planet is currently home to seasonal liquid water flow, but only when the conditions are just right.
This conclusion is a game changer because liquid water is one of the pillars in facilitating life as we know it. Since our Earth is the only world that we can study in close detail we only have this as an example. With that said, even a little bit of water is a pretty major milestone. While a little bit of seasonal water does not seem to support a massive technology wielding civilization, it could very well be responsible for microbial life. Water, the magic life supporting ingredient, has not been a part of our understand of the red planet until now. Could this mean there is life somewhere other than Earth? Does this allow us to learn how life can exist in totally different scenarios? Will this mean we can begin to catalog the functional aspects of biology on a scale grander than just our home? All good questions, but still further down the road. Right now the big question is where is all this seasonal water coming from? Deliquescence, the process of chemically extracting and creating liquid water from the atmosphere, is one of the many ways this phenomena can be explained. Perhaps there are large frozen ice deposits that thaw out in the spring and summer thus allowing a temporary flow of water. Maybe there are aquifers beneath the surface in some places. We just don't know, yet.
Like all great discoveries in science, one answer will bring up a plethora of other questions. For now the search for the water's origin is a pretty big question. As these questions get answered we will start to see a more clear picture of Mars. After all, in humanity’s mind, Mars has gone from being a star, to a god, to a world filled with fire, to a dead planet, to a dry desolate world, to now being a place where seasonal change allows for water to flow down certain slopes. Decades of work have gone into finally understanding that water does occasionally move on Mars’s surface. This is a great example of how we can’t force scientific discovery, you really do have to just go observe the evidence and go with the flow.