On the first day of the new year, NASA's New Horizons spacecraft flew past and photographed the "snowman-shaped" Ultima Thule, the most distant and possibly the oldest cosmic body ever observed by a spacecraft.
The image: The object, which looks a little like a snowman, is what's known as a "contact binary", a body consisting of two connected spheres measuring 19 miles (31 kilometers) in length.
Pictured: The first colour image of Ultima Thule, taken at a distance of 137 000km at 4:08 Universal Time on 1 January 2019, highlights its reddish surface.
The two spheres spiralled closer to each other and eventually got stuck together. After it coasted through, NASA selected Ultima Thule as the next observational target and set a course.
Scientists have ascertained that the object takes about 15 hours to make a full rotation.
It's no simple matter to reach the outer solar system, so NASA is making the most of the opportunity it has with the New Horizons probe. Frozen in time, the object may allow NASA to collect data that it hopes can give us further insight into the history and formation of our solar system.
In March, NASA and the New Horizons team announced their decision to use Ultima Thule as a nickname for the second stop on their solar system tour, which is officially known as 2014 MU69, a formula that designates when it was discovered.
Flyby data solved one of Ultima's mysteries, showing that the Kuiper Belt object is spinning like a propeller with the axis pointing approximately toward New Horizons. Before Ultima Thule was intercepted by the New Horizons spacecraft, scientists knew nearly nothing about it, but they were eager for a glimpse of what's thought to be an nearly unchanged relic from our solar system's earliest days. While Earth anxiously sucks in a deep breath of anticipation, scientists have finally determined the color of Ultima Thule.
Ultima was chosen as a follow-up object for study, coming after New Horizons' 2015 flyby of Pluto and its moons.
Less than 1 percent of all the data gathered by New Horizons during the flyby has been downlinked to Earth.
The team has dubbed the larger sphere "Ultima" (19km across) and the smaller sphere "Thule" (14km across). "New Horizons has set a new bar for state-of-the-art spacecraft navigation", said Stern.
"I don't think we have stressed enough, so I really want to say, what this spacecraft and this team accomplished is unprecedented.
He added: "It is going to revolutionise our knowledge of planetary science".
Though they do not appear to have impact craters, there could be hills and ridges, with the neck connecting the two lobes being one of the steepest slopes.
As a preserved relic from that original time, Ultima Thule also promises to shed light on the so-called Kuiper Belt, or Twilight Zone, in which hundreds of thousands of objects reside well beyond Neptune.