See the moon's marvels in 3-D
NASA / GSFC / ASU / N. Burton-Bradford
A "natural bridge" on the moon looks unnaturally cool when the red-blue image is seen through 3-D glasses.
Alan Boyle writes:NASA’s moon orbiter is sending back shots of lunar curiosities that look even curiouser when you see them through 3-D glasses.
One of the most curious sights is the natural bridge you're looking at right here, near King Crater on the moon's far side. The two-dimensional view may look like nothing more than two black spots at the left edge of the frame — but through red-blue specs, it's clear that a wedge of sunlight is shining down to the bottom of the chasm below.
The bridge is about 20 meters (65 feet) across and roughly 8 meters (25 feet) wide. Based on interpretations of the slanting shadows, the depth of the chasm ranges from 6 to 12 meters (20 to 40 feet).
This is just one of several natural bridges spotted by NASA's Lunar Reconnaissance Orbiter during its survey of the moon. The team in charge of the Lunar Reconnaissance Orbiter Camera says in its image advisory that such features are formed when material from the surface falls into an empty lava tube beneath. The case of King Crater is even more unusual in that the bridge is not formed out of volcanic basalt, but rather out of rock that was melted by an ancient impact.
Paul Spudis, a senior staff scientist at the Lunar and Planetary Institute, discusses the bridge's origins on his "Once and Future Moon" blog and notes that the formation is transitory, just as natural bridges on Earth are.
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