• January 24, 2022
 Amy’s Everyday Astronomy: A Cosmic Snowman on the Edge of the Solar System

Amy’s Everyday Astronomy: A Cosmic Snowman on the Edge of the Solar System

On New Year’s Day the New Horizons spacecraft flew past the most distant object yet explored in our solar system, Ultima Thule. Though the flyby was quick, it will take up to 20 months for NASA to download all the data collected.

However, data that has already come in has given us interesting insight and information about this far away world. Initially thought to be a peanut or bowling pin shaped object, the truth is much more intriguing. Ultima Thule is actually two objects that began a slow waltz a couple billion years ago.

All of the planets in our solar system formed when matter left over from a long ago supernova explosion began to coalesce into larger bodies, a process known as accretion. In the Kuiper Belt, not all objects were able to complete the process to become full planets or dwarf planets, like Pluto. Instead, they remain small and irregular and are then considered planetesimals.

This was the case for Ultima and Thule, as the two bodies that make up this cosmic snowman are now being known. These two objects began their slow dance around each other until gravity eventually pulled them into a gentle contact, forever locking them into a conjoined partnership.

This new theory of its formation comes from the lack of impact evidence where the two bodies converge.

Believed to be spinning in a similar fashion to a plane propeller, it has a rotation period of about 15 hours. Interestingly, Ultima Thule is also definitively red in color, according to new images released by NASA.

This is consistent with findings of other irradiated objects in the Kuiper Belt. Images also reveal that there seems to be a lack of impact craters on the surface, though the two objects do have a mottled appearance. And Ultima Thule isn’t as reflective as one might expect from an icy world on the edge of the solar system. It only reflects about 13% of the sunlight that hits its surface.

As of now, less than 1% of all data collected by New Horizons has been downloaded and analyzed by mission scientists. So, we can expect more detailed photos and information to come throughout the year. And I’ll continue to bring you updates as they become available.


For a daily dose of Everyday Astronomy with Amy, like and follow her Facebook Page; to read previous articles, click here.

Amy Cooley

A native El Pasoan, Amy Cooley attended Parkland High School before beginning her studies in physics at EPCC. With her love of dark skies increasing, she transferred to New Mexico Tech University where she earned her degree in Astronomy. Moving back to El Paso in 2008, she now wants to share her love of the cosmos with the city she calls home.

Related post