A new study suggests that ice clouds over early Mars could provide heat to allow running water on the Red Planet.
U.S. researchers have used a computer model to predict that ice clouds in Mars’ atmosphere may have had a greenhouse effect. The earth also experiences a greenhouse effect, which occurs when gases in the atmosphere retain heat from the sun.
Today, Mars enjoys a cold, desert climate. It is believed that all existing water is in the form of ice due to the extremely low temperatures on the planet. However, there is ample evidence to suggest that rivers, lakes, and even oceans once existed on Mars.
In fact, scientists announced in February that they had created a new map designed to identify the best sources of water ice on Mars.
Scientists have long been trying to explain what allowed Mars to have the great rivers and lakes that they believe existed in the ancient past of the planet.
The researchers involved in the latest study were interested in possible explanations. They created a three-dimensional, or 3D, a model of the Martian atmosphere.
The study was led by Edwin Kite, a professor and planetary scientist at the University of Chicago. He said the study led to a major discovery – that ice on the surface of Mars may have caused the greenhouse effect. The study was published recently in Notices of the National Academy of Sciences.
When water or ice on the planet’s surface evaporates – which happens when it turns from solid to steam – creates humidity. Humidity is formed when there is a high level of water vapor in the atmosphere. Money helps clouds form.
Researchers say that high clouds provide more of a warming effect than low clouds. High clouds are more likely to form if only small areas are covered with ice, such as poles or mountain tops. They believe this was the case on Mars.
Kite said past research has looked at similar theories, but the research is based on ideas related to the behavior of our own planet. “In the model, these clouds behave in a very different way from Earth,” Kite said in a statement.
“Building models based on the Earth” understandings will simply not work, he said, adding, “this is not at all like the Earth’s water cycle, which moves water rapidly between the atmosphere and the surface.”
Kite said his team model suggests that once the water moved into the early Martian atmosphere, it probably stayed for a much longer time. “And that creates the conditions for long-term high-altitude clouds.”
The team said it hoped the new theory could help scientists resolve a huge “gap” between existing evidence for Mars water and the ability to support it with physics and chemistry.
Kite added that the persistence of NASA’s Mars explorer should be able to test the theory in several ways. For example, small rock material can be collected and studied in an attempt to recreate the past atmospheric pressure on Mars.
Recent research and future research on how Mars has gained and lost heat can also help scientists identify other inhabited worlds, Kite said. “Mars is important because it is the only planet we know of that had the ability to sustain life – and then lost it.”
I’m Brian Lynn.
Brian Lynn wrote this story for VOA Learning English based on reports from the University of Chicago and Proceedings of the National Academy of Sciences. Caty Weaver was the editor.
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Words in this story
3D – adj. having or appearing to have length, depth and height
steam – n. small drops of liquid in the air
inhabited – adj. able to sustain life