Go Climb a Mountain ... on the Moon!

 

The Apennine Mountains will stand out boldly tonight (Oct. 24) on the 8-day-old moon. All you need to see them is a pair of binoculars and a partly cloudy sky. The mountain range defines the southeastern "shore" of Mare Imbrium, the Sea of Showers. You may also notice the 68-mile-wide crater Plato on the sea's northern shore. Bob King 

I'm not a technical mountain climber. I don't use rope, only hands, legs and occasionally my rear end to clamber up and down the rocks. I don't mind expending the extra energy to hike to a hilltop because the wide-open view makes me feel happy inside and reminds me that I'm just a particle in the great stream of being. 

A small telescope will show the Apennines, two additional mountain ranges and several prominent craters in the region tonight (Oct. 24). Mt. Hadley, located at the northeastern end of the chain, is the moon's highest peak. Bob King

With a small telescope and a little imagination, you can experience similar vistas without even putting on boots. Tonight the 8-day-old waxing gibbous moon reveals one of the best known lunar mountain ranges, the Apennines, named for the Apennine Mountains in Italy. The range curls around the southeastern "shore" of the Sea of Showers, also known as Mare Imbrium, one of the moon's most prominent seas.

An orbital view from 1971 shows the Apennines and Apollo 15 landing site. NASA 

Easily visible in binoculars tonight, look for a partially-shadowed arc above the center of the lunar disk that curves upwards toward Mare Serenitatis (Sea of Serenity), a big, dark circle that forms one of the eyes of the Man in the Moon. Because the sun is just rising on the range, its many peaks are beautifully highlighted against the shadows they cast. To fully experience how rugged the terrain is here, use a small to modest telescope and a magnification between 40x and 150x.

An asteroid slammed into the moon 3.9 billion years ago and excavated the Imbrium Basin which later flooded with lava to become the present-day Mare Imbrium (Sea of Showers). Bob King

The range extends for about 370 miles (600 km), nearly the same length as the state of South Dakota.  Based on rocks gathered by the Apollo 15 mission we know that it formed about 3.85 billion years ago when an asteroid struck the moon and punched out the Imbrium Basin, an enormous impact crater. Later, dark, basaltic lavas from below the surface filled the basin layer by layer and then cooled and solidified into the lunar sea we know today. For a while it was a true sea but one composed of molten rock the consistency of boiling honey.

An asteroid more than 150 miles (240 km) across slammed into the moon to create the 720-mile-wide (1,160 km) Imbrium Basin.  LPI, Leanne Woolley, David A. Kring

The Apennines, along with several other nearby mountain ranges, were formed when the impact uplifted and crumpled the moon's crust. Together they now trace a series of concentric rings centered on Mare Imbrium. The arc of the Apennines — evident even in binoculars — traces out part of that ring.

Its highest peak, Mt. Hadley, towers over the moonscape at 18,000 feet (5,486 meters), just 2,000 feet shy of Alaska's Denali. The Apollo 15 mission landed within a short distance of the peak in July 1971 at a site called Hadley Rill, a ancient groove that once channeled lava. They collected 170 pounds (77 kg) of moon rocks there including the famous Genesis Rock, one of the oldest found on the moon with an age of 4.1 billion years. 

One of the Apollo 15 astronauts took this photo of Mt. Hadley. This image is just part of a much larger panorama. Tracks left by the lunar rover are visible in the foreground. Lunar mountains have smooth contours due to bombardment by micrometeorites. With no atmosphere to slow them down, the particles strike the moon at many thousands of miles an hour and slowly grind away the craggy peaks over billions of years. NASA

From Hadley's summit we could gaze out across the silent lava plain and imagine the cataclysm that happened here so long ago that's still stamped into the rocks at our feet.

As the moon fills out in the coming nights the Apennines range will brighten, whiten and lose its shadowy edge. It remains in view through Nov. 6. There are more than 3,000 peaks here, providing lots of exciting (and safe) climbing opportunities.