Video: New Horizons animation

Five years ago Tuesday, NASA’s New Horizons spacecraft barreled by Pluto for a high-speed encounter that gave humanity its first close-up look at a distant world that puzzled astronomers and planetary scientists for nearly a century. Scientists are now planning how to go back.

The final days before NASA’s New Horizons probe barrels in on its next destination on Jan. 1, 2019, should prove eventful, with scientists trying to sort out whether a distant mini-world detected by the Hubble Space Telescope more than three years ago may actually be a swarm of icy objects.

Maps of Pluto charted using data from NASA’s New Horizons mission appear to show two huge mountains scientists said Monday could be ice volcanoes, a discovery that would set the distant dwarf planet apart among its neighbors in the outer solar system.