It’s a strange little world.
At 4 billion miles from Earth, MU69 (also nicknamed Ultima Thule) is the farthest-away object a human spacecraft has ever visited. For the past few years, scientists have labeled MU69 as an unknown, mysterious “puzzle.” After the 13-year-old New Horizons spacecraft eventually swooped by the frozen rock on New Years Day 2019, the object graduated to a snowman-shaped frozen rock.
Now, after receiving new images of MU69, planetary scientists suspect that both of its “lobes” are flattish, too.
“The larger lobe, nicknamed ‘Ultima,’ more closely resembles a giant pancake, and the smaller lobe, nicknamed ‘Thule,’ is shaped like a dented walnut,” the Johns Hopkins Applied Physics Lab (where the mission is headquartered) detailed online.
These latest observations, which revealed the object in a new light, create more puzzles. Other solar system objects similar to MU69 — like comets, for instance — have rounder, though still imperfect, forms.
“It would be closer to reality to say Ultima Thule’s shape is flatter, like a pancake,” Alan Stern, who heads the New Horizons mission, said in a statement. “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.”
New Horizons — the legendary spacecraft that captured these images of MU69 — shot the latest sequence of pictures on Jan. 1, 2019, as the spacecraft departed MU69 at 31,000 mph and hurtled deeper into the black abyss of space, toward still-unknown destinations.
These certainly aren’t the last images we’ll see of MU69, nor are they the closest. But they are the final views New Horizons captured of this far-off, icy world.
MU69 is a place of major scientific intrigue. It’s preserved in a ring of ancient frozen objects, called the Kuiper Belt, that form a ring around the solar system. Out here, temperatures drop to nearly absolute zero, or negative 460 degrees Fahrenheit, which is as cold as it can get naturally.
Scientists believe that out here in this remote frigid realm, objects like MU69 have been frozen in pristine condition since the onset of the solar system some 4 billion years ago.
It’s an artifact of our ancient cosmic past.
As New Horizons beams more images through the solar system, we’ll almost certainly continue seeing weird, unprecedented stuff.