Last updated on April 20, 2014 at 21:20 EDT
The Moons Largest Impact Basin
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The Moon's Largest Impact Basin

November 30, 2012
The South Pole-Aitken (SPA) basin is the largest and oldest recognized impact basin on the moon. It's diameter is roughly 2,500 km or 1,550 miles. The moon's circumference is just under 11,000 km, meaning the basin stretches across nearly a quarter of the moon. In the LROC WAC mosaic below, which is centered on the middle of the basin, you can see SPA as an area of relatively low reflectance extending from the crater Aitken in the north and all the way down to the South Pole. Topographic data from LOLA can also help to give a sense of the enormous effect the SPA impact had on the moon - the basin is more than 8 km (5 miles) deep. A crater within a crater within a basin: the interior of the South Pole-Aitken basin is one of the most compelling destinations on the moon. NAC image M103196768LE; scene width is 520 m [NASA/GSFC/Arizona State University].