Lab Experiment Emulates Mars’s Boiling Water
We all know that Mars is a dry and dusty planet that, nonetheless, has hidden sources of water. None of it flows on the surface in a stable way — that is, it doesn’t move in rivers or pool in lakes anymore. The water that DOES exist is underground. When it somehow reaches the surface, the temperatures and pressures produce boiling water. The action of the water is so intense that it can set off dry avalanches and blast sediments out to the surface.
How can Mars water boil if the surface temperatures are cold? As anybody who has taken a physics or chemistry class would immediately recognize, water’s boiling point isn’t just dependent on temperature. It is also affected by atmospheric pressure. Here on Earth, the atmospheric pressure at sea level allows water to boil at 100 C (212 F). Where I live (at 9200 feet or 2818 meters), the water boils at 90 C (194 degrees F). The higher the altitude, the lower the air pressure, and the lower the temperature needed to boil water on Earth.
On Mars, the atmospheric pressure is so low that water can boil at as low as 0 C (32 F). Most of Mars’s water is frozen underground, but it can be warmed up enough during the Martian summer and spring that water will start to flow from underground and boil when it reaches the surface. And, according to some research done here on Earth by a group of scientists in Paris, France, the boiling action may be enough to explain some Martian surface features seen in high-resolution images.
Reproducing Mars on Earth
The scientists used a decompression chamber to simulate various atmospheric conditions where water flows. The flows produced in conditions that we see here on Earth produced water flows that simply seeped into sand. Once the water dried, there was no trace it had ever been there. However, when they dialed in the conditions for Mars and plugged in a small ice cube beneath the sand, the water produced by the melting ice started to boil as soon as it reached the surface. It also released gases, which caused the ejection of sand grains. They formed small ridges at the front of the flow. Over time, those ridges became unstable and actually produced avalanches of dry sand. The process was even more violent at lower pressures. The entire process left behind a series of ridges very similar to what is seen on Mars.
Of course, the action of boiling water is only one way that ridges form on the Red Planet. The wind plays a role in creating dunes and ridges, as well. However, this experiment also shows that more than one process is at work on Mars, and there are likely others, too.
Until we can actually get to Mars ourselves and do more in-depth chemical and physical studies of the ridges and dunes scattered across the planet, experiments such as these help us understand what we’re seeing on the Red Planet. For a planet without surface water, it does seem that the appearance of Mars really does owe a lot to the action of water.
