A photograph showing what Arrokoth looks like. Credit: NASA/Johns Hopkins APL/SwRI.

Unraveling the Secrets of Arrokoth: NASA’s New Horizons Sheds Light on Distant Kuiper Belt Object’s Structure

NASA's New Horizons mission has unveiled fascinating discoveries about the enigmatic Kuiper Belt Object, Arrokoth. The spacecraft's detailed analysis of Arrokoth's major lobe reveals a unique structure comprised of large mounds, which are believed to be the very building blocks of the lobe itself. As scientists delve deeper into these findings, they uncover new clues about the formation of planetesimals, the building blocks of planets, and ultimately, the early stages of our solar system's development.


NASA’s New Horizons mission has provided valuable insights into the Kuiper Belt Object Arrokoth’s major lobe, revealing that its large mounds could be the very building blocks of the lobe. Arrokoth, the most distant and primitive object ever explored by a spacecraft, is considered a “contact binary,” meaning it consists of two objects or lobes that once orbited each other before smoothly merging long ago.

Examining Arrokoth’s Unique Structure

Mission instruments observed that the lobe is made up of 12 distinct mounds clustered around a larger central mound. Researchers examined the shape, size, orientation, reflectance, and colors of each mound, using stereoscopic images to identify depressions, scarps, pit chains, and patches of bright material that indicated where the mounds actually met.


Alan Stern, New Horizons principal investigator from the Southwest Research Institute in Boulder, said, “We found that the mounds are similar in many ways, including their sizes, reflectivities, and colors.” Stern presented these results at the 54th Lunar and Planetary Science Conference in Texas.

A Surprising Discovery About Planetesimal Formation

The findings suggest that the mounds were likely individual components that existed before Arrokoth’s assembly, indicating that bodies of the same size formed as precursors to Arrokoth itself. “This is surprising and a new piece in the puzzle of how planetesimals, the building blocks of planets like Arrokoth and other Kuiper Belt objects, come together,” Stern added.

A Brief Introduction to Arrokoth

Arrokoth is a trans-Neptunian object located in the Kuiper Belt, a region of the solar system beyond Neptune’s orbit. Discovered in 2014, Arrokoth was visited by NASA’s New Horizons spacecraft in January 2019, providing scientists with valuable data on its composition and structure. Its unique “contact binary” formation offers important clues about the early stages of the solar system’s formation and the processes involved in the creation of planetesimals, the building blocks of planets.


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Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

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