Holy planetesimal formation, Batman! Ultima Thule's no snowman - it's a friggin' pancake

New images of the distant Ultima Thule object have surprised scientists

New images of the distant Ultima Thule object have surprised scientists

Based on the new images, the larger lobe (nicknamed Ultima) appears to more closely resemble a giant 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", he added.

Though these are not last Ultima Thule images, as many more are to come- but these images are the final view of New Horizons captured of the KBO (officially named 2014 MU69) as it raced away at over 31,000 miles per hour (50,000 kilometers per hour) on January 1. The image to the left is an "average" of ten images. The probe aced this encounter in July 2015, revealing the dwarf planet to be a spectacularly diverse world of surprisingly varied and rugged landscapes.

It's not that easy to get accurate photos of the complete form of Ultima Thule, considering factors like distance from the sun, the side facing the light, and New Horizon's 50,000 km/h speed. This object is about 21 miles (34 kilometers) long and lies 1 billion miles (1.6 billion km) beyond Pluto's orbit. The bottom view is the team's current best shape model for Ultima Thule. But that impression changed shortly before closest approach, which occurred just after midnight on New Year's Day and brought the probe within 2,200 miles (3,540 km) of the mysterious body.

Ultima Thule first seemed to be an amalgam of two vaguely spherical objects, but the new image is telling us that appearances can be deceiving, especially at 4.1 billion miles away.

The incredible images confirmed some predictions and dispelled others, revealing MU69 to be a snowman-shaped world with a rusty red hue that spins end-over-end like a propeller.

At 4 billion miles from Earth, MU69 (also nicknamed Ultima Thule) is the farthest-away object a human spacecraft has ever visited. The direction of Ultima's spin axis is indicated by the arrows. Most of the time, we can only make guesses based on images our terrestrial telescopes and a few orbital satellites have captured of celestial objects few spacecraft have reached.

"The shape model we have derived from all of the existing Ultima Thule imagery is remarkably consistent with what we have learned from the new crescent images", said Simon Porter, a New Horizons co-investigator from the Southwest Research Institute, who leads the shape-modeling effort.

Scientists' understanding of Ultima Thule has changed as they review additional data. By noting which of these stars went dark as Ultima blocked them out, mission scientists were able to map out the object's (surprisingly flat) shape.

"While the very nature of a fast flyby in some ways limits how well we can determine the true shape of Ultima Thule, the new results clearly show that Ultima and Thule are much flatter than originally believed, and much flatter than expected", said Hal Weaver, New Horizons project scientist from the Johns Hopkins Applied Physics Laboratory.

"Nothing quite like this has ever been captured in imagery", said Stern.