Scientists have finally discovered what’s hidden inside mysterious blobs buried beneath the Red Planet’s equator, and the answer may help plan for life on Mars.
Scientists used new data from ESA’s Mars Express spacecraft to discover ice several kilometers beneath the planet’s surface.
The spacecraft has visited this part of the planet before, but this is the first time it has raised more questions than answers. Mars Express studied the wind-sculpted Medusae Fossae Formation, which now contains the ice, fifteen years ago.
Back then, Mars Express discovered massive deposits estimated to be 2.5km (1.6 miles) deep beneath the formation, but no one knew what they contained. Scientists now have an answer, and the results show that the deposits are 3.7 kilometers (2.3 miles) deeper than previously thought.
In fact, the spacecraft discovered so much ice that if it all melted, Mars would be covered in 1.5 to 2.7m (4.9 to 8.9ft) of water. That’s enough water to fill the Red Sea.
“Excitingly, the radar signals match what we’d expect to see from layered ice, and are similar to the signals we see from Mars’s polar caps, which we know to be very ice-rich,” said lead author Thomas Watters of the Smithsonian Institution in the United States.
The findings, published in the journal Geophysical Research Letters, represent the largest amount of water ever discovered in this region of the Red Planet. The water could be critical for future human missions to Mars, which would land near the equator rather than the ice-covered polar caps.
“While the discovery of layers of water ice within the dusty subsurface of Mars does not provide any new hope for finding alien life on Mars, it may help humans become the aliens on Mars in the future,” Dr. Darren Baskill, an astronomy lecturer at the University of Sussex, told BBC Science Focus.
“Mars was once a wet planet, but liquid water is no longer found there. So, while this large source of water-ice deposits is hundreds of meters underground, its proximity to the equator is convenient, and raises the prospect of mining this water-ice in the future, making human exploration of Mars a little more feasible.”
But separating the ice from its dusty surroundings could be difficult. After all, the Medusae Fossae Formation consists primarily of windswept dust piles.
This is also why it was so difficult to determine what was inside it. Rather than ice, the deposits could have simply been more dust, but new radar data has narrowed the possibilities.
“Given how deep it is, if the MFF [Medusae Fossae Formation] was simply a giant pile of dust, we’d expect it to become compacted under its own weight,” said co-author Andrea Cicchetti from Italy’s National Institute for Astrophysics.
“This would result in a much denser image than what we currently see…” And when we simulated how different ice-free materials would behave, nothing replicated the MFF’s properties; we need ice.”
The formations are most likely made of layers of dust and ice, with an outer layer of dust preventing the ice from melting.
Because the ice is at the planet’s equator, it could not have formed under Mars’ current climatic conditions. This suggests that the ice is a remnant of a previous epoch, challenging current scientific understanding of the Red Planet’s climate history and raising new questions for future research.