A recent study led by Brown University researchers sheds new light on the formation of canyon-like channels known as canyons on Mars, suggesting that water from melting ice may have played a significant role.
Martian craters bear a striking resemblance to the craters formed by water erosion of melting glaciers found in the dry valleys of Antarctica. The research team, including Brown planetary scientist Jim Head, developed a model to simulate conditions that could lead to liquid water on Mars’ surface, experiencing periods of above-freezing temperatures.
The team discovered that when Mars is tilted on its axis by about 35 degrees, its atmosphere thickens enough to allow brief episodes of melting in rocky places. The researchers compared the data from their model to periods in Martian history when craters in the Terra Sirenum region expanded rapidly downward from higher elevations, and found that the presence of water was necessary to explain this phenomenon.
„Early in the history of Mars, we know from a lot of our research and the research of others that water was running on the surface with valley networks and lakes. But about 3 billion years ago, all that liquid water was lost, and Mars became a very dry or what we call a polar desert. Even after that, „Here we show that even though Mars’ axis has tilted 35 degrees in recent times, the ice and snow have warmed enough to melt, bringing liquid water back up to the temperature. Drop, it refreezes,” said Jim Head, professor of geological sciences at Brown.
Previous theories suggested that Martian craters were carved by freezing carbon dioxide evaporated from the soil. However, the height and erosion of the craters has led many scientists to hypothesize the involvement of meltwater from glaciers. Confirming the existence of liquid water on Mars is challenging because of the planet’s generally cold temperatures, 70 degrees below freezing.
The new findings indicate that gully formation was driven by periods of ice melt and the evaporation of carbon dioxide from the freeze-thaw during other parts of the year. The researchers suggest that this process may have repeated itself over the past several million years, with the most recent event occurring around 630,000 years ago.
Despite doubts about the possibility of meltwater, researchers believed that the theory of meltwater on Mars was accurate due to direct observations of similar features in Antarctica.
The study, published in the journal Science, builds on previous research conducted by the team decades ago, studying the Martian planets.
„Everyone is always looking for environments that are conducive not only to the formation of life, but also to its preservation and continuation. Any microbes that might have evolved early on Mars would be in places where they could be comfortable in the ice. Comfortable or thriving in liquid water. In the cold Antarctic environment, for example, the few organisms that do exist often occur in stasis, waiting for water, „Chairman explained.