The good news is that there is an ocean of water beneath the surface of Mars, large enough to cover the entire planet to a depth of one mile (1.6 km). The bad news is that this reservoir is so deep and inaccessible that it might as well be in another galaxy.
Mars is one of the most frustrating planets humanity has ever encountered. Over the last two centuries, there has been a constant pendulum swing as evidence of life there or abundant water for future Earth colonies has been found, only to have hopes repeatedly dashed by more data.
A new study by a UC Berkeley-led team has combined hope and disappointment in the same paper Proceedings of the National Academy of Sciences.
Using seismic data collected by NASA's Insight lander, scientists were able to analyze this using computer rock physics models similar to those used to map aquifers and oil fields on Earth. What they found was that the readings collected by Insight were best explained by the presence of a deep layer of fractured igneous rock saturated with liquid water beneath the Red Planet's surface.
James Tuttle Keane/Aaron Rodriquez, courtesy of Scripps Institution of Oceanography
There's an ocean's worth of water locked up in that rock, but the problem is that it's inaccessible. According to the team, the layer is 11.5 to 20 km (7 to 13 miles) below the surface, meaning that reaching that massive aquifer, much less exploiting it, would be a major engineering challenge on Earth, to say the least, not to mention the harsh environment of Mars.
But there's some good news. For one, all that water means there's another place where microbial life could theoretically exist. For another, it helps explain the geological history of Mars.
Three billion years ago, Mars was a watery world with an ocean dominating one hemisphere. Over thousands of years, the planet's atmosphere diminished due to the lack of a magnetic field to protect it from solar winds. As the atmosphere diminished, most of the water evaporated into space, leaving only ice caps and some permafrost deposits.
At least that's the accepted theory. If the Berkeley analysis is correct, it's possible that much of this ancient sea seeped through cracks in the rocks and settled deep down.
“Understanding the Martian water cycle is critical to understanding the evolution of the climate, surface, and interior,” says Vashan Wright, a former UC Berkeley postdoctoral researcher. “A useful starting point is to determine where there is water and how much of it there is.”
Source: UC Berkeley