New Moon

A talented duo of U.S. moon robots is making man even more familiar with his nearest neighbor in space. From the prying cameras of Surveyor 3, which landed on the moon last April, and Orbiter 4, which last week was circling the moon, scientists were provided with movies, color pictures and a wealth of new insight into ancient lunar secrets.

Blue-Green Earth. In Washington, NASA showed the first moon movies, pieced together from still pictures shot by Surveyor during its first lunar day. One film strip showed the spacecraft's claw digging a small trench in the soil. Another, taken at sunset, followed the edge of lunar night as it swallowed Surveyor's lengthening shadow and moved on across the crater until only a few high clumps of rocklike material remained lighted against a black sky.

NASA also released several Surveyor color photographs shot through red, green and blue filters by the craft's black-and-white TV camera and reconstituted on earth to give a good approximation of colors as they appear on the moon. The most striking of these showed a blue-green, cloud-mottled crescent in the dark lunar sky--Surveyor's view of the earth. A color version of Surveyor's black-and-white pictures of the earth eclipsing the sun (TIME, May 5, 1967) showed the dark disk of the earth silhouetted against a yellow-orange halo, caused by the refraction of sunlight through the earth's atmosphere.

Color photographs of the lunar surface beneath a deep black sky confirmed the findings of Surveyor I that the moon was grey. "The grey varies in shade from pale to very dark," said U.S. Geological Survey Scientist Eugene Shoemaker, "but it appears to be still basically all grey."

Sea Debris. Orbiter 4 was even more informative. Its overhead and closeup picture of the Humboldt Crater--located at the right edge of the visible face of the moon and difficult to see through terrestrial telescopes--suggested to Astrogeologist Harold Masursky that the crater is "very young" geologically and was probably created by the impact of a meteorite only a few million years ago. The event was so recent, Masursky believes, that the floor of Humboldt is still gradually rising. This "isostatic rebound," as he calls it, has produced an obvious fracture in the crater floor--evident for the first time in the Orbiter 4 photograph.

Orbiter has also revealed for the first time a large rill, or canyon, in an area near the south pole that is not visible from earth. The 200-mile-long and 10-mile-wide canyon extends from the edge of a large and still unnamed crater, and was created, Masursky believes, by the impact of the same meteorite that formed the crater. The spacecraft may also have helped determine if the lunar "seas" or flat dark areas are part of the moon's original structure or were formed by the impact of gigantic meteorites. If these lunar basins were formed by the impact of meteorites, Masursky and other scientists believe, their periphery should be littered by debris tossed outward by the collision. Orbiter pictures of the 300-mile-wide Sea of Rains show that the hummocklike structures visible through telescopes on its northern rim are indeed debris.

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