Arrokoth Is a Snowman Made by Gentle Collision

Arrokoth, an object in the Kuiper Belt, is about 35 kilometers (22 miles) long and shaped like a partly flattened snowman. NASA’s New Horizons flew past it on January 1, 2019, coming within 3,538 kilometers (2,198 miles). Arrokoth orbits about 6.5 billion kilometers (4 billion miles) from the Sun.

Its two lobes formed separately, circled each other, then touched and merged gently inside a cloud of particles early in the history of the solar system. A hard crash would have crushed or scattered them. The smooth, intact shape shows that planet building began with soft contacts between small bodies. At the time of the flyby, Arrokoth was the most distant object ever explored up close.