If my dog Pluto were sitting on that planet July 14, would he be likely to catch a glimpse of New Horizons as it zooms by?

The closest New Horizons will get to Pluto is about 7,770 miles (12,500 kilometers) above the surface. At this distance, the spacecraft would be only 45 arcseconds across, around the size of Jupiter as viewed from Earth. New Horizons will be traveling at 8.6 miles per second (13.8 km/s) relative to Pluto, meaning it will zip through the sky at 3 arcminutes per second. That’s much slower than an International Space Station pass on Earth, but still fast enough that the spacecraft will go from horizon to horizon in a couple of hours.

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