ARC-1990-A91-2007

Range : 350,000 miles This image of the western hemisphere of the Moon was taken through a green filter by Galileo at 9:35 am PST. In the center is the Orientale Basin, 600 miles in diameter, formed about 3.8 billion years ago by the impact of an streroid-size body. Orientale's dark center is a small mare. To the right is the lunar near side with the great, dark Oceanus Procellarum above and the small, circular, dark Mare Humorum Below. Maria are broad plains formed mostly over 3 billion years ago as vast bassaltic lava flows. To the left is the lunar far side with fewer maria, but, at lower left, the South-Pole-Aitken basin, about 1200 miles in diameter, which resemble Orientale but is much older and more weathered and battered by cratering. The intervening cratered highlands of both sides, as well as the maria, are dotted with bright, young craters. This image was 'reprojected' so as to center visibility of small features.