Arrokoth is a binary space object consisting of two lobes attached by a bright, narrow neck. The two lobes were likely once two objects that had merged in a slow collision. It is, and it is a trans-Neptunian object located in the Kuiper belt. It is 36 km long and composed of two planetesimals nicknamed Ultima (21 km across) and Thule (15 km across) that are joined along their principal axes. It is the first pristine planetesimal visited by a spacecraft, and the most distant object ever visited.
Ultima Thule was the binary’s former name, metaphorical meaning of any distant place located beyond the “borders of the known world.”
In Germany, Nazis believed in the historical Thule as the ancient origin of the “Aryan race.” This led to the name of the binary being changed last November into 486958 Arrokoth, which in the Native American language it means “sky.”
Oldest Known Space Object In The Solar System Reveals More Details On Planetary Formation
Three new studies on the ancient space objects reveal relevant data about its origin, formation, geology, composition, color, and temperature. The data gathered will give input on planetesimals. Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. They formed 3.8 billion years ago in the solar system, which makes them valuable in studies of the formation of it.
By the looks of it, Arrokoth didn’t change in the billions of years that passed since it formed. It is red, very cold, covered in methanol ice and unidentified complex organic molecules, and its surface is smooth. “Arrokoth looks the way it does not because it formed through violent collisions, but in more of an intricate dance, in which its component objects slowly orbited each other before coming together,” said William McKinnon, a New Horizons co-investigator.
In the beginning, they were two separate bodies. But gravitation and patience got them to become thermodynamically stable. But only in this icy region of Kuiper’s belt, far from the hot temptations of the Sun. They got closer and closer, 7 miles per hour until they’ve become one.