Dec. 28 (UPI) -- Mercury's poles are marked by large craters. Icy deposits hide inside. Now, scientists think they know how the ice got there.
Researchers at the University of Maine modeled the glaciation process on the planet closest to the sun.
Most of Mercury is rather hot. But a few of its polar craters remain in permanent shadow, allowing for temperature low enough to sustain ice deposits. The glaciers are thought to be less than 50 million years old and 165-feet thick in some places.
Scientists used data collected by Earth-based radar to characterize the shape, thickness and distribution of Mercury's polar ice.
Mercury has no atmosphere that could generate snow or ice deposits. The simulations designed by the University of Maine research team showed a comet impact was the most likely original source of ice.
The model found little evidence of flow, suggesting the ice deposits have remained still and stable over the last several million years.
"We expect the deposits [on Mercury] are supply limited, and that they are basically stagnant unmoving deposits, reflecting the extreme efficiency of the cold-trapping mechanism" of the polar terrain, researchers said in a news release.
Researchers used the University of Maine Ice Sheet Model to run their simulations. The model was designed to recreate the movement and evolution of ice sheets and glaciers on Mars and Earth.
James Fastook, a professor of computer science and researcher at the Climate Change Institute, and his colleagues shared the results of their simulations in the journal Icarus.