Ultima Thule Is More Pancake Than Snowman

Ultima Thule's crescent shape

Our first impressions of Ultima Thule weren’t entirely accurate. As new data makes the more than four-billion mile journey to Earth, the Kuiper belt object’s shape is coming into well, shape. The latest images were stitched together into a “departure movie.” Let’s take a look.

The imaging team on New Horizons were able to trace the part of Ultima Thule not illuminated by the Sun as the spacecraft executed its flyby. What they found surprised them. Ultima Thule isn’t spherical. The initial idea of two round lobes is giving way to two much flatter lobes.

Here’s how the mission team thought Ultima Thule looked based on images captured before its flyby.

And here’s the new look ten minutes after closest approach.

“We had an impression of Ultima Thule based on the limited number of images returned in the days around the flyby, but seeing more data has significantly changed our view,” says Principal Investigator Alan Stern. “It would be closer to reality to say Ultima Thule’s shape is flatter, like a pancake. But more importantly, the new images are creating scientific puzzles about how such an object could even be formed. We’ve never seen something like this orbiting the Sun.”

Because Kuiper belt objects are believed to be undisturbed remnants of our solar system’s formation, this new view of Ultima Thule raises new questions.

Hal Weaver, New Horizons project scientist, had this to say about the new shape of Ultima Thule. “This will undoubtedly motivate new theories of planetesimal formation in the early solar system.”

New Horizons is continuing to beam back all its data from its recent close flyby. One of the satellite dishes at the Goldstone facility is receiving data right now. Here are a couple of cool data points from the transmission happening this morning:

Round-trip light time: 12.31 hours.

Data rate from New Horizons to Goldstone: 1.68 kb/sec.

Check out the Deep Space Network website and look out for the NHPC designation. That’s New Horizons.

The spacecraft will spend the better part of 20 months beaming data back to Earth from the Ultima Thule flyby. Later this month, we should see the best images (including color and detailed geologic) yet.

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