Pluto's Tiny Dumbbell Moon and a New Target for New Horizons

A new image from the New Horizons spacecraft finally completes the entire Pluto family portrait, showing Pluto's smallest (known) moon, Kerberos. And surprise! It's double-lobed! That's actually only mildly surprising; a lot of small asteroids and comets are not single, lumpy objects, but are instead shaped like bowling pins (or dumbbells, or dog bones). Something like 10-15 percent of all near-Earth asteroids are double-lobed (we have decent statistics on that particular group because they get ...