Traces of ancient rivers and lakebeds on Mars seem to show Mars was once flowing with water, but new research suggests moisture was most likely episodic and related to periods of volcanic activity.
Recent climate models have suggested Mars' atmosphere is too thin to heat the planet enough for water flow, Brown University reported. The Sun is also believed to have been dimmer and cooler billions of years ago than it is today.
"These new climate models that predict a cold and ice-covered world have been difficult to reconcile with the abundant evidence that water flowed across the surface to form streams and lakes," said James W. Head, professor of earth, environmental and planetary sciences at Brown University and co-author of the new paper with Weizmann's Itay Halevy. "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."
The water flow patterns on Mars suggest water flow on the planet occurred about 3.7 billion years ago, which is also believed to be the same time there was a massive volcanic outpour. This suggests the water flow and volcanic activity on Mars were connected. On Earth volcanic activity actually cools the atmosphere due to the thick ash particles, but the researchers believe it may have had the opposite effect on the early red planet.
Researchers created a climate model that predicted how sulfuric acid would react with dust in the Martian atmosphere. The results suggest the sulfuric acid particles would have latched onto dust particles, reducing the atmosphere's ability to deflect the Sun's rays. The sulfur dioxide would also produce a modest greenhouse effect, which would have warmed the planet's equator.
"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 findings suggest as volcanism decreased in the Red Planet's older years so did the water flow. The findings could provide insight into where potential clues to ancient life could be found on the planet.
"Life in Antarctica, in the form of algal mats, is very resistant to extremely cold and dry conditions and simply waits for the episodic infusion of water to 'bloom' and develop," Head said. "Thus, the ancient and currently dry and barren river and lake floors on Mars may harbor the remnants of similar primitive life, if it ever occurred on Mars."
The findings were published in a recent edition of the journal Nature Geoscience.
