The latest images of the solar system's most distant object ever explored show Ultima Thule, an icy celestial object located 6.6 billion kilometers (4.11 billion miles) from Earth, taking on the form of something us Earthlings are quite familiar with. Located about 1.6 billion kilometers (1 billion miles) past Pluto, the 32-kilometer-long (20-mile-long) body consisting of two fused spheres looks like a rust-colored snowman.
Announcing their findings at a press conference (starting at the 3-hour mark) on Wednesday, scientists can confidently say the two spheres were formed billions of years ago at the beginning of the Solar System when small, icy pieces combined, slowly spiraling closer to each other until ultimately becoming stuck together. The lower, larger lobe is officially named Ultima and the other Thule because, you know, scientists only have so much time on their hands.
NASA’s New Horizons spacecraft first snapped photos of the mysterious object on New Year’s Day, sending back fuzzy images that made the out-of-this-world object look like a blurry peanut. At the time, researchers weren’t able to confirm Ultima Thule’s exact parameter and other relevant planetary features.
The new data shows the bi-lobe rotates with a period of about 15 hours, give or take an hour. When combined with the light curve and reflectivity of the surface, scientists were able to determine that the surface is so dark it is comparable to potting soil. The “neck” where the two lobes connect is the brightest and is consistent with having fine-grain materials that have settled there due to gravity.
According to co-investigator Carly Howett, the red coloring is consistent with other objects in Ultima Thule’s class, such as the coloration observed in parts of Pluto’s large moon Charon, and is probably the result "of the irradiation of exotic ices”. No obvious impact craters were seen in the images currently available, but a resolution of about 150 yards per pixel revealed suggestions of hills and ridges as well as changes in elevation greater than 1 kilometer (0.6 miles).
Other datasets will be downloaded over the course of the next two years, revealing more to scientists about other, smaller scale variations. More information will be released in the following days and weeks.
“Think of New Horizons as a time machine that has brought us back to the very beginning of our Solar System, to a place where we can observe the most primordial building blocks of the planets,” said Geology and Geophysics Lead Jeff Moore.