576 Megapixel View of the Moon from NASA (Public Image) by TheShot

Public-domain image.

A new 24,000-pixel-square mosaic from NASA's Lunar Reconnaissance Orbiter shows the Moon's nearside as never before. Acquired during a two-week period in December 2010, the 1,300 black-and-white frames create a full-disk mosaic measuring 24,000 pixels across.

"As the Moon rotated under LRO's orbit," explains LROC team leader Mark Robinson (Arizona State University), "the ground track progressed from east to west (right to left in this mosaic)." The image run was timed to keep the Sun high up in the lunar sky but not straight overhead (its altitude varied from 69° to 82°). This created enough shadowing to define crater rims and other topography crisply, unlike the shadow-free view that we see during a full Moon. The combined image shows slight banding where the 1,024-pixel-wide swaths were stitched together.

The image looks dark because Robinson and his team have kept the Moon as it really is: dark. On average, the lunar surface reflects only about 12% of the sunlight that strikes it. So a full Moon really isn't dazzlingly bright — it only looks that way to our eyes because of the contrast with the black sky around it.