Spacecraft flies by little Pluto, finding it bigger than thought

An unmanned spacecraft, New Horizons, flying past Pluto after a decadelong journey, has proved that the planet is larger than all other known objects beyond the orbit of Neptune, the US space agency NASA said.

Measurements by the spacecraft as it swept past Pluto on Tuesday indicated the diameter of the dwarf planet was 2,370 kilometers, plus or minus 19 km. That's about 80 km 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.