As people all over the world nursed their hangovers from the night before, the members of NASA’s staff that have continued to work despite the partial government shutdown rang in the new year by making history.

“Congratulations to NASA’s New Horizons team, Johns Hopkins Applied Physics Laboratory, and the Southwest Research Institute for making history yet again,” said NASA Administrator Jim Bridenstine. “In addition to being the first to explore Pluto, today New Horizons flew by the most distant object ever visited by a spacecraft and became the first to directly explore an object that holds remnants from the birth of our solar system. This is what leadership in space exploration is all about.”

In the early hours of 2019, NASA’s New Horizons spacecraft flew past Ultima Thule, the most distant celestial object ever reached by a manmade device—more than a billion miles past Pluto.

At left is a composite of two images taken by New Horizons’ high-resolution Long-Range Reconnaissance Imager (LORRI), which provides the best indication of Ultima Thule’s size and shape so far. An artist’s impression at right illustrates one possible appearance of Ultima Thule based on the image at left. The direction of Ultima’s spin axis is indicated by the arrows. (NASA)

At that distance, it will take more than two years for NASA to receive the full breadth of data collected by New Horizons, but blurry images of the distant celestial body taken during New Horizon’s approach (which closed to within approximately 2,200 miles of the rock) appear to show a bowling pin-shaped body that measures around 2o miles long and 10 miles wide.

“New Horizons performed as planned today, conducting the farthest exploration of any world in history—4 billion miles from the Sun,” said Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. “The data we have look fantastic and we’re already learning about Ultima from up close. From here out the data will just get better and better!”


The Kuiper belt is a ring of icy objects orbiting the sun at such a distance that temperatures hover only 30 or 40 degrees above absolute zero (approximately –459.67°F). At that distance, the dim light of the sun is nearly indiscernible from other stars. The resulting deep freeze hinders or completely prevents all chemical reactions within the rock, keeping it exactly as it was shortly after the solar system first formed.

“Everything that we’re going to learn about Ultima—from its composition to its geology, to how it was originally assembled, whether it has satellites and an atmosphere, and that kind of thing—is going to teach us about the original formation conditions in the Solar System that all the other objects we’ve gone out and orbited, flown by, and landed on can’t tell us because they’re either large and evolve, or they are warm. Ultima is unique,” Stern said.