486958 Arrokoth is a small, icy trans-Neptunian object located in the Kuiper Belt.

It is the most distant and most primitive object ever explored by a spacecraft.

Key Mission & Discovery

Discovery:

It was discovered on 26 June 2014 by astronomer Marc Buie and the New Horizons Search Team using the Hubble Space Telescope.

Flyby:

NASA's New Horizons spacecraft flew past Arrokoth on 1 January 2019 at a distance of approximately 3,500 kilometres from its surface.

Significance:

It is a "time capsule" from the early solar system, offering a pristine record of how planetesimals formed approximately 4.5 billion years ago.

Physical Characteristics

Shape:

It is a contact binary, consisting of two distinct lobes joined by a narrow neck, often described as looking like a "partially flattened snowman".

Dimensions:

The object is approximately 36 km (22 miles) long. The larger lobe is nicknamed "Ultima" and the smaller "Thule".

Color & Composition:

It has an notably red surface, likely due to complex organic molecules called tholins.

Methanol ice has also been detected on its surface.

Density:

Scientists estimate it has an extremely low density, similar to fluffy snow on Earth, suggesting it formed through a very gentle merger of two objects.

Nomenclature

Official Name:

Formerly nicknamed Ultima Thule, it was officially named Arrokoth in November 2019.

Meaning:

"Arrokoth" is a word from the Powhatan/Algonquian language meaning "sky" or "cloud".