A handful of subglacial lakes have been drilled into on Earth, including Lake Vostok in Antarctica. These projects are not easy and it can take years to dig below several kilometers of ice. But the scientific payoff is huge – and every time we drill down, we find life.
Previously on Mars, we have found evidence for water trickling on the surface, known as recurring slope lineae (RSL). These features are short-lived, however, with the water quickly evaporating in the low-pressure environment on the Martian surface.
It’s long been theorized, though, that there may be more stable bodies of liquid beneath the surface, as evidenced in this research. And if that’s the case, it provides an exciting new habitat for microorganisms of the past or present on Mars.
“It’s very important to know if this [reservoir] is a unique thing,” said Dr Orosei. “If it’s regional, not local, then you can have a whole system of subglacial lakes similar to what you see on Earth. You would have ways for living organisms, if they existed, to have a much larger environment and perhaps move around.”
To answer this, the team hope to use more data from Mars Express over the coming years. The spacecraft is aging, though, and it’s running out of fuel, so time is of the essence.
Getting to these sources of liquid water in the future may also be difficult. Drilling operations on Earth require complicated machinery, something we simply don’t have on Mars. The upcoming European ExoMars rover in 2020 will be able to drill about 2 meters (6.6 feet) below the surface, but that may not be enough to get close to subsurface reservoirs of water like this.
There are still unanswered questions about this liquid water discovery. It’s not clear if it’s a large body, or simply water seeping in between rocks. What it does suggest, though, is that liquid water exists beneath the surface of Mars.
On Earth, liquid water almost always means life. Coupled with the recent discovery of the building blocks of life on Mars, and the possibility it once had a more habitable environment, evidence is building that the Red Planet may not be so dead after all.
“It’s likely that this is what we would describe as a habitat,” said Dr Orosei. “It has at least some of the conditions that terrestrial microorganisms would need to survive.”