There is something new on the moon: valleys.

The moon's crust is being stretched and that has resulted in the formation of minute valleys in a few small areas on the lunar surface, reports NASA after scientists viewed new images from NASA's Lunar Reconnaissance Orbiter spacecraft.

It is thought this geologic activity occurred less than 50 million years ago, which is considered recent compared to the moon's age of more than 4.5 billion years.

The images captured by the camera aboard the Lunar Reconnaissance Orbiter show small, narrow trenches that are typically much longer than they are wide. This indicates the lunar crust is being pulled apart at these locations.

These linear valleys, known as graben, form when the moon's crust stretches, breaks and drops down along two bounding faults. These graben systems have been found across the lunar surface.

"We think the moon is in a general state of global contraction because of cooling of a still hot interior," said lead study author Thomas Watters of the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum in Washington, D.C. "The graben tell us forces acting to shrink the moon were overcome in places by forces acting to pull it apart. This means the contractional forces shrinking the moon cannot be large, or the small graben might never form."

The weak contraction suggests that the moon, unlike the terrestrial planets, did not completely melt in the very early stages of its evolution. Rather, observations support an alternative view that only the moon's exterior initially melted forming an ocean of molten rock.

The takeaway: The pulling apart of the lunar crust means the moon is still active, and thanks to the Lunar Reconnaissance Orbiter, we can see that process up close.

The study findings were published in the journal Nature Geoscience.

--From the Editors at Netscape