Shadow of a Doubt
The lofty structures surprised selenologists because pictures from Lunar Or biter I and Surveyor 1 had revealed smoother plains broken primarily by high mountains and crater rims but not by sharp outcroppings.
"They might be blocks of material ejected from a crater by the impact of some object," speculates Dr. Thor Karlstrom, one of the USGS scientists who studied the pictures for NASA's Langley Research Center. Or the rocks could be volcanic material ejected through faults in the moon's crust - a view which adds to the impressive evidence already accumulated by Lunar Orbitcr I that the moon has had the same turbuleut geological past as the earth. The structures might also be eroded cones of old volcanoes. "Any of these possibilities could conceivibly be correct," says Karlstrom.
In any case, the formations probably will have little effect on the first U.S. lunar-landing plans. All the outcroppings are in an area that has already been given low priority as a possible landing site.