New Horizons visited Arrokoth earlier this year NASA/JHUAPL/SwRI/Thomas Appéré

Goodbye Ultima Thule, hello Arrokoth. The space rock that NASA’s New Horizons probe sped past earlier this year has been given a new name: Arrokoth, which means “sky” in the Powhatan and Algonquian languages.

The rock’s official designation is 2014 MU69, but the New Horizons team nicknamed it Ultima Thule, a mythological reference to a distant and mysterious land. The nickname faced a significant backlash after a reporter at Newsweek pointed out that the Nazi party used the phrase to refer to the mythical homeland of the Aryan people.

Read more: Distant space rock Ultima Thule formed in a slow and gentle collision

On 12 November, NASA held a naming ceremony to give MU69 its new official name Arrokoth. The name was chosen based on the local Native American culture in Maryland, where the New Horizons mission control centre is based.


As New Horizons flew past Arrokoth, it took a wealth of data, which is still being sent back from the spacecraft to Earth for analysis. So far, we know that it has a strange shape like a pair of pancakes stuck together on the pan, which indicates that its two lobes merged in a relatively gentle collision. It also appears to be covered in methane or nitrogen ice, giving it a red tinge.

Objects like Arrokoth were the building blocks that made our solar system’s planets, so researchers hope that studying these frigid rocks could help us understand how planets form.

Discover more about NASA’s missions: Explore four NASA space centres on a New Scientist Discovery tour