Arrokoth is one of thousands of ‘icy worlds” in the Kuiper Belt, or the outer zone of the solar system that lies beyond Neptune. It is the farthest object in space that has been explored by a human space-craft. It was discovered in 2014 using the Hubble Space Telescope. Arrokoth is a double-lobed object and resembles a snowman. It is believed it may have ancient ‘gaseous ice’ stored deep within it from when the object first formed billions of years ago.

The New Horizons space craft launched in January 2006 flew past Pluto on July 2015. In 2019, New Horizons continued on its journey and explored Arrokoth, which is about a billion miles from Pluto. Arrokoth is located in the Kuiper belt and translates to “sky,” a term from the language of the Native American Powhatan tribes.

Recently scientists proposed a model to explain Arrokoth’s ice core. This model suggests that this feat of perseverance isn’t unique to Arrokoth but to many objects in the Kuiper Belt, which formed around 4.6 billion years ago. The model suggests that these primitive ices can be locked deep within the interiors of these objects for aeons.

Arrokoth is so cold that for more ice to sublimate - or go directly from solid to a gas, skipping the liquid phase within it - the gas it sublimates into first has to have travel outwards through its porous, sponge-like interior. To move the gas, the ice must also sublimate and this causes a domino effect. As it gets colder within Arrokoth, less ice sublimates, less gas moves, it gets even colder, and so on. Eventually, everything just effectively shuts off, and you’re left with an object full of gas that is just slowly trickling out.

From the Science Pages