Mountains on Pluto, chasms on Charon thrill scientists

Post-flyby images from NASA's New Horizons probe show Pluto is a surprisingly active world in the deep freeze of the outer solar system, with jagged 11,000-foot-high mountains of frozen water dusted with a veneer of nitrogen, methane and carbon monoxide ice amid smooth plains and jumbled terrain that defies easy explanation, scientists reported Wednesday.

A distinct paucity of impact craters implies processes at work now or in the geologically recent past that have resurfaced large areas of Pluto, smoothing out the pockmarks so familiar on other small bodies. What powers that resurfacing is not yet known, but scientists are hopeful New Horizons eventually will provide the answer.