LAUREL, Md. — Ultima Thule, an icy world 4 billion miles from the sun, looks like a big snowman.
At a news conference on Wednesday, scientists working with NASA’s New Horizons mission released several images that the spacecraft took as it flew by on Jan. 1.
The scientists now say with confidence that Ultima Thule long ago was two bodies that got stuck together, what they call a “contact binary.”
“Two completely separate objects that are now joined together,” said S. Alan Stern, the principal investigator for the mission.
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It also looks pristine, almost unchanged since it formed out of a disk of dust and gas that orbited the sun more than 4.5 billion years ago. Studying it could offer insights to how Earth and the other planets formed.
A day ago, scientists released a blurry picture of the small body also known by its official designation 2014 MU69 taken from a distance of half a million miles, taken before the flyby.
The object looked sort of looked like a fuzzy bowling pin.
The first batch of science data from the flyby arrived on Earth on Tuesday afternoon. More than 100 scientists, including Heidi B. Hammel, a planetary scientist and a media liaison for the science team, gathered at 8 p.m. for a look.
“Everybody was there,” Dr. Hammel said. “They all wanted to see it. The picture goes up and everybody applauds and cheers. Immediately, the chatter starts.”
A second shift of scientists worked on the data overnight, presenting more detailed analysis during a science team meeting on Wednesday morning.
New Horizons Glimpses the Surface of Ultima Thule
NASA’s New Horizons spacecraft flew past the most distant object ever visited.
Planetary scientists have never before seen a close-up of an object like Ultima Thule. It is likely an icy fragment that coalesced more than 4.5 billion years ago and which has remained in a deep freeze of the solar system’s Kuiper belt ever since, some 4 billion miles from the sun.
If it is indeed a pristine planetesimal, a building block of the planets, studying it will offer clues to how our planet and its neighbors formed.
Even clearer pictures are arriving on Earth in another transmission. The full set of data will be a long time coming — trickling across the solar system over the next 20 months.
Kenneth Chang has been at The Times since 2000, writing about physics, geology, chemistry, and the planets. Before becoming a science writer, he was a graduate student whose research involved the control of chaos. @kchangnyt
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