Some curious formations on Mars were believed to be lava flows. Tens of thousands of conical hills, most with crater-like tops, surrounded by deep outer channels where some mysterious flowing liquid forged a path, all lead researchers to think these could be volcanoes on the Red Planet.
Scientists have now uncovered what these flows may be — and it's not quite as exciting as bright red lava. Think more in terms of brown, gooey mud. That's what is believed to ooze out of these volcanic formations.
The findings of the study were published in Nature Geoscience on Monday.
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It's hard to know exactly what's going on on Mars. Through close observation and replication of certain conditions, scientists can discern a pretty close and good idea of what happens up on the Red Planet.
We have mud volcanoes here on Earth, so it's not such a huge surprise that they could be forming on other planets too. Scientists from Lancaster University in the U.K., and the Institute of Geophysics at the Czech Academy of Sciences, have found out that under Mars' very low atmospheric pressure and temperature conditions, mud can flow just like lava would on Earth. Thus, mud volcanoes on Mars.
"We performed experiments in a vacuum chamber to simulate the release of mud on Mars," said planetary scientist Lionel Wilson of Lancaster University.
Wilson continued "This is of interest because we see many flow-like features on Mars in spacecraft images, but they have not yet been visited by any of the roving vehicles on the surface and there is some ambiguity about whether they are flows of lava or mud."
Moist sediments stuck beneath Mars' surface may have been pushed up through underground pressure, which in turn creates these mud volcanoes. This is what the researchers set out to find out.
The team's experimental set up included a low-pressure cylindrical chamber, which was carefully pressurized at seven millibars to simulate Mars' atmospheric pressure for the team's 15 experiments.
Mud was then poured over sand that then cooled to a temperature similar to Mars' surface, -20 degrees Celcius (-4 degrees Fahrenheit). The way mud flowed was then observed by the scientists.
The team found that the effect of the mud flows in their simulated Mars experiments were fascinating. The water in the mud began to boil and evaporate, in doing so latent heat from the vapor is absorbed. Ultimately, this cools the mud and a crust freezes on its surface.
As geophysicist Petr Brož of the Czech Academy of Sciences explained, "our experiments show that even a process as apparently simple as the flow of mud - something that many of us have experienced for ourselves since we were children - would be very different on Mars."