Ten years to reach Plato

Wow! It takes almost 10 years for a spacecraft to fly from Earth to the planet Plato, which is located in the same solar system! The universe is really big!

The New Horizons spacecraft has completed a historic fly-by of Pluto, NASA says, making its closest pass at7:49 a.m. ET.

The unmanned, piano-sized spacecraft was traveling nearly 31,000 miles per hour when it passed about 7,750 miles above Pluto. 

New Horizons will continue traveling out into the Kuiper Belt, a region scientists think is filled with thousands of other small, icy worlds. Scientists say the probe will continue sending back data about Pluto for several months.

New Horizons was launched from Cape Canaveral, Florida, on Jan. 19, 2006, and traveled more than 3 billion miles to reach Pluto. It's the first mission for any nation to Pluto and its five moons. 

The mission completes what NASA calls its initial reconnaissance of the classical solar system. The space agency has now sent probes to Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.