Asteroid Ultima Thule Christened ‘Arrokoth’ In Native American Tribute

Composite image of the primordial contact binary Ultima Thule now named Arrokoth taken by NASA’s New Horizons spacecraft. A contact binary is made of two smaller, ice-rich asteroids that became joined at the hip so to speak during a previous slow collision. Together they’re 22 miles (36 km) long and currently about 4 billion miles from Earth. NASA / JPL-Caltech / JHUAPL

Remember Ultima Thule? That was the temporary name given to the remote asteroid New Horizons flew by on January 1, 2019. The name referred to the distant unknown, an idea or object at the limit of our understanding. And indeed the 22-mile-wide contact binary asteroid fits the bill, orbiting the sun every 298 years with an average distance of half a billion miles beyond Pluto.

In a fitting tribute to the farthest flyby ever conducted by spacecraft, the Ultima Thule has been officially named Arrokoth (AR-uh-koth), a Native American term meaning “sky” in the Powhatan/Algonquian language. NASA’s New Horizons team proposed the name to the International Astronomical Union after getting permission from the Powhatan tribal elders. Earlier this month, Powhatan elders joined team members at NASA’s headquarters in a ceremony to make the name official.

Rev. Nick Miles, of the Pamunkey tribe, plays a drum and sings a traditional Algonquin song at the opening of the Arrokoth naming ceremony. NASA / JHUAPL / Southwest Research Institute

“The name ‘Arrokoth’ reflects the inspiration of looking to the skies and wondering about the stars and worlds beyond our own,” said Alan Stern, New Horizons principal investigator. “That desire to learn is at the heart of the New Horizons mission, and we’re honored to join with the Powhatan community and people of Maryland in this celebration of discovery.”

New Horizons launched in January 2006, conducted a historic flyby of Pluto on July 14, 2015 and swung by Arrokoth on New Year’s Day 2019 in the farthest flyby ever conducted. Arrokoth is not alone in the great emptiness of the Kuiper Belt, a vast region beyond Neptune where thousands of small, icy asteroids slowly circuit around the sun. But it’s damn cold out there. The surface temperature on the sunny side of Arrokoth rises to a bone-chilling –351° F (–213° C) with nighttime lows around 438° F below zero (–261° C).

Illustration showing how Arrokoth may have formed. NASA / JHUAPL / SwRI / James Tuttle Keane

It’s thought that contact binaries like Arrokoth form when two separate asteroids in close orbit slowly merge into one but in a relatively gently way that preserves their distinct shapes. And by the way, the name Ultima Thule won’t be going away just yet. Ultima remains the nickname for the larger of the two bodies and Thule the smaller.

New Horizons’ had a lot of miles to cover so it took years to arrive at Pluto and more than 3 years longer to reach Arrokoth. KBOs stands for Kuiper Belt Objects. NASA / JHUAPL

In accordance with IAU naming conventions, the discovery team earned the privilege of selecting a permanent name for the asteroid. Both the New Horizons mission and the Hubble Space Telescope, the instrument used to discover the asteroid in 2014, operate out of Maryland, which is also the ancestral homeland region of the Powhaten people. That made Arrokoth a perfect fit. I like the sound of it, at once ancient and yet with Star Trekky overtones.

No matter who you are or what you believe, we all seek meaning in the universe and a connection to the stars. When you can combine culture and science in a name, it’s a recognition of many paths we might take to get there.