Exploratory missions to Mars, such as NASA’s Curiosity Rover, have provided more and more evidence that Mars at one time was warm enough for water to flow on its surface.
Now a new study published in the journal “Nature Geoscience” has found that those ancient, warm periods on the Red Planet probably took place in brief and sporadic spurts of time.
“This new analysis provides a mechanism for episodic periods of heating and melting of snow and ice that could have each lasted decades to centuries,” said James W. Head, the study’s co-author and a professor of earth, environmental and planetary sciences at Brown University, in a university press release.
The researchers from Brown University in the U.S. and Israel’s Weizmann Institute of Science, suggest that the periods that saw warmth and flowing water on Mars some 3.7 billion years ago may have been the result of the expulsion of gases due to volcanic activity.
The U.S./Israeli study combined the impact of volcanic activity with fresh climatic data that gathered by the various Mars probes to create and update new Mars climate models.
Studying those newer climate models, researchers found several factors that would make it difficult for a warmer and wetter Red Planet to exist.
They said the Mars atmosphere was so thin it would be difficult, if not impossible, for the planet to retain enough heat to allow for water to flow freely on its surface. They also suggested that many years ago our sun wasn’t quite as powerful as it is today.
But ongoing research of the Red Planet’s geological features has suggested that when water flowed some 3.7 billion years ago, there was a lot of volcanic activity taking place, with gigantic volcanoes spewing out large amounts of lava.
Along with lava, ash and other , volcanoes also pumps out a good amount of sulfur dioxide into the atmosphere.
While atmospheric sulfur dioxide here on Earth has been linked to the production of acid rain and global cooling, the researchers in this study believe that this gas may have affected the atmosphere of Mars differently.
To reach their findings the research team generated a model that examined how sulfuric acid might react with the extensive amounts of dust in the ancient Martian atmosphere.
The models suggested that the particles of sulfuric acid attached themselves onto the dust particles in the Martian atmosphere. The combined particles of dust and sulfuric acid would have reduced the ability to reflect the rays of the sun.
And they also found that the sulfur dioxide gas pumped into the atmosphere by the volcanoes would also have created a slight greenhouse effect that provided just enough warmth to the equatorial region of Mars to allow water to flow.
Professor Head, who spent a number of years conducting research in Antarctica, said that he thinks the climate of ancient Mars may have been comparable to the frigid, desert-like conditions Antarctica’s McMurdo Dry Valleys.
“The average yearly temperature in the Antarctic Dry Valleys is way below freezing, but peak summer daytime temperatures can exceed the melting point of water, forming transient streams, which then refreeze,” Head said. “In a similar manner, 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.”
The researchers said that warm Martian temperatures and flowing water on its surface ended with the cessation of the Red Planet’s volcanic activity.