WASHINGTON — The first pictures from the unseen side of Mercury reveal the wrinkles of a shrinking, aging planet with scars from volcanic eruptions and a birthmark shaped like a spider.
Some of the 1,213 photos taken by NASA’s Messenger probe and unveiled Wednesday help support the case that ancient volcanoes dot Mercury and that it is shrinking as it gets older, forming wrinklelike ridges.
But other images are surprising and puzzling.
The spidery shape captured in a photo is “unlike anything we’ve seen anywhere in the solar system,” said mission chief scientist Sean Solomon of the Carnegie Institution of Washington.
The last time a NASA spacecraft went to Mercury was Mariner 10 in 1975.
It took pictures of just 45 percent of the planet.
