Ultima Thule, floating in the moonlit sky

Early on New Year’s Day, the New Horizons probe, which has already lived up to its name by obtaining the most detailed pictures yet of Pluto, continued its tour of the Kuiper Belt Objects (KBOs) at the fringes of the solar system by visiting Ultima Thule, at 4 billion miles from Earth the most distant object yet visited by one of humanity’s emissaries. Pronounced “Tu-lay” (to the surprise of The Engineer), Ultima Thule orbits the sun at more than a billion miles beyond Pluto, and New Horizons returned a photograph to Earth taken a distance of around 18,000 miles from the object.

Existing images of Ultima Thule suggested that the space rock was shaped approximately like a bowling pin, but New Horizon’s images reveal that this was mistaken. About 21 miles long and 10 miles wide, the KBO is dark red and consists of two roughly spherical lobes joined at a narrow neck. “That bowling pin is gone. It’s a snowman if anything at all,” commented mission principal investigator Alan Stern.