Photo shows the largest of the newly detected graben found in highlands of the lunar farside. The broadest graben is about 500 meters (1,640 feet) wide and topography derived from Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) stereo images indicates they are almost 20 meters (almost 66 feet) deep. Credit: NASA/Goddard/Arizona State University/Smithsonian Institution)
The Moon isn’t what it’s cracked up to be! It is more a stretch, according to new data from NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft.
Imagery taken by LRO has shown the Moon’s crust is being stretched, forming minute valleys in a few small areas on the lunar surface.
This activity – geologically speaking – is “recent” – less than 50 million years ago. And given the Moon’s age of more than 4.5 billion years, that’s like yesterday!
In scanning the Moon, the Lunar Reconnaissance Orbiter Camera (LROC) has found small, narrow trenches typically much longer than they are wide. This indicates the lunar crust is being pulled apart at these locations.
“Graben” systems
These linear valleys are known as graben. They form when the Moon’s crust stretches, breaks and drops down along two bounding faults. A handful of these graben systems have been found across the lunar surface.
“This pulling apart tells us the Moon is still active,” said Richard Vondrak, LRO Project Scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “LRO gives us a detailed look at that process.”
The thought now is that the Moon is in a general state of global contraction because of cooling of a still hot interior.
“It’s exciting when you discover something totally unexpected and only about half the lunar surface has been imaged in high resolution,” said Mark Robinson of the School of Earth and Space Exploration at Arizona State University. He is also principal investigator of LROC.
“There is much more of the Moon to be explored,” Robinson concluded.
By Leonard David