Little Pluto Bigger Than Scientists Thought As Flyby Looms

Little Pluto is a little bigger than anyone imagined. On the eve of NASA's historic flyby of Pluto, scientists announced Monday the New Horizons spacecraft has nailed the size of the faraway icy world. Measurements by the spacecraft set to sweep past Pluto on Tuesday indicate the diameter of the dwarf planet is 1,473 miles, plus or minus 12 miles. That's about 50 miles bigger than previous estimates in the low range. Principal scientist Alan Stern said this means Pluto has a lower density than thought--which could mean an icier and less rocky interior.