In images released last Thursday by NASA's New Horizons spacecraft, dwarf planet Pluto features breathtaking views of majestic icy mountains, streams of frozen nitrogen and and haunting low-lying hazes. But what has scientists so stunned? The scenes are a little too familiar. "We did not expect to find hints of a nitrogen-based glacial cycle on Pluto operating in the frigid conditions of the outer solar system," said Alan Howard, a member of the mission's Geology, Geophysics and Imaging team from the University of Virginia, Charlottesville.