Image of the Month: Tycho Crater’s spectacular central peak

The peak at the centre of Tycho Crater on our Moon has been imaged by the Lunar Reconnaissance Orbiter spacecraft. Let’s take a look at this spectacular mountain of the Moon.

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Majestic Moon mountain (Image credit: NASA/GSFC/Arizona State University)

One of the best-known lunar craters, Tycho is not especially large at some 85 km across. However it is very clearly visible on the Moon’s southern face. Bright and with prominent rays of material radiating from it, Tycho is a young crater; there has been little time for the slow and steady rain of micrometeorites to erode it. We are fairly certain that Tycho is about 108 million years old, whereas most lunar craters are much older, dating pact to the Late Heavy Bombardment of 3.9 billion years ago. How can we be so sure of Tycho’s age? The impact event which formed it was so violent that debris was hurled across thousands of kilometres. Samples of glass found by the crew of Apollo 17 who landed 2000 km away are believed to be ejecta from Tycho and have been radiometrically dated to 108 mya.

NASA’s LRO recently took this evocative image of the steep slopes of Tycho’s central peak illuminated by the morning Sun. This mountain, rising 2 km (1.2 miles) above the crater floor, is believed to be made of material from deep below the lunar surface that rebounded back up after being compressed in the impact. The peak is casting great black shadows across the  floor of the crater. This floor is covered in “impact melt”, the cooled residue of a sea of molten rock which bubbled in the crater basin immediately after the impact event. Since then all has been quiet. I wonder when spacesuited humans will disturb this silence.