Climate models show that with the ice-cold temperature in Mars, the Red Planet never had the capability to have liquid water.
This, however, presents a conundrum because geological features, such as deltas, lake basins and river valleys found on the Martian surface, suggest the existence of flowing water at some points of the planet's history. Now, a new study published in Nature Geoscience on Nov. 17 is bridging the gap between climate models and geological evidence of liquid water.
Study researchers Itay Halevy from the department of earth and planetary sciences at the Weizmann Institute of Science in Israel and James Head III from the department of earth, environmental and planetary sciences at Brown University in Rhode Island posited that the discrepancy could have something to do with the large-scale eruption of ancient Martian volcanoes more than 3.7 billion years ago.
Martian volcanic activities could be attributed to the warmth that made flowing water possible on the planet's surface and both liquid water and warm temperature probably occurred episodically on the Red Planet.
The researchers posit that powerful eruptions of a series of volcanoes in the planet's history spewed the greenhouse gas sulfur dioxide into the atmosphere; the emission brought about temporary warmth on the planet's surface, which resulted in brief periods when the temperature became favorable enough for the planet's frozen water to thaw. This period could have lasted decades and even possibly centuries.
"We find that volcanism can bring the temperature on early Mars above the melting point for decades to centuries, causing episodic periods of stream and lake formation," Head said.
Although widespread volcanic activities on Earth often cools the temperature because sulfuric acid particles and ash reflect the rays of the sun, the researchers thought that the effects of sulfur would be different in the dusty Martian atmosphere.
Halevy and Head created a model that simulated how sulfuric acid particles would react given Mars' dusty atmosphere. They found that sulfuric acid formed thin coating around the dust particles reducing the latter's ability to reflect the rays of the sun. This resulted in a modest greenhouse effect that brought about a temperature just warm enough to allow water to flow.
"In our simulations, strong greenhouse warming by SO2 is accompanied by modest cooling by sulphate aerosol formation in a presumably dusty early Martian atmosphere. The simulated net positive radiative effect in an otherwise cold climate temporarily increases surface temperatures to permit above-freezing peak daily temperatures at low latitudes," the researchers wrote.