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The Cassini spacecraft’s radar sweep of Saturn’s largest moon Titan in January revealed a portion of what appears to be a 110 mile (180 kilometer) diameter impact crater.

If its impact origin is confirmed it would only be the fourth such crater discovered on Titan, a surprisingly small number.

Impact cratering is pervasive in our solar system, and the number of craters on the surface of a moon or planet can reveal its age in just the same way the accumulation of potholes on a highway reveals how long ago the asphalt was laid.

Earth's Moon remains heavily pockmarked because it has no significant weather or geological processes to wipe its face clean. Earth, similarly bombarded over the eons, shows many scars from relatively recent impacts that have not had time to weather away. Craters are common on several other satellites of Saturn.

“If Titan's surface had the same density of craters that other Saturnian moons have, there should be thousands of craters,” said Ralph Lorenz of the Johns Hopkins University Applied Physics Laboratory. ”With radar having examined about 10 percent of Titan's surface, we have only three definite craters, and perhaps a half-dozen probables.”

Far too few

The trio of impact craters confirmed to date are named Menrva, Sinlap and Ksa and have diameters of 273 miles (440 kilometers), 50 miles (80 kilometers) and 17 miles (28 kilometers), respectively.

Titan’s thick nitrogen atmosphere hinders the formation of impact craters less than about 12 miles (20 kilometers) in diameter, because smaller space rocks burn up before they reach the surface. This is one reason the shrouded moon’s crater count is so modest.

As Cassini continues to map up to 30 percent of Titan’s surface at radar wavelengths the crater tally is set to grow.

“We've seen three craters on 10 percent of the surface, so we will probably find another 10 to 30. Maybe there are 30-100 in total, although we will need a follow-on mission to Titan to find and document them all,” Lorenz told SPACE.com.

Still, researchers consider the surface nearly pothole free when it should be on the road to ruin. Something yet to be determined must be keeping the crater count down.

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See some of our TPODs on Titan:  Titan versus Venus, Titan's Strange Atmosphere and Seen Through Titan's Haze  
 

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