had a very happy New Year when its New Horizons spacecraft successfully flew by mysterious Ultima Thule, a space rock located a billion miles past Pluto in the Kuiper Belt. We now know a lot more about that cosmic body, and it looks like a snowman.
New Horizons principal investigator Alan Stern called the mission "a technical success beyond anything ever attempted before in spaceflight." Stern described Ultimate Thule as being about the size of Washington DC and as reflective as garden-variety dirt.
Ultima Thule was once two separate space rocks that joined together, known as a contact binary. The New Horizons team has named the individual lobes, calling the smaller one Thule and the larger one Ultima.
NASA shared a graphic showing how an object like Ultima Thule forms: "as a rotating cloud of small, icy bodies started to combine. Eventually, 2 larger bodies remained & slowly spiraled closer until they touched, forming the bi-lobed object we see today."
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The spacecraft will send back much more data on Ultima Thule, helping NASA learn more about how planets form. We can also look forward to higher-resolution images giving us an even better look at this epic space snowman.