Composite of two images (left) taken by New Horizons' high-resolution Long-Range Reconnaissance Imager (LORRI) and an artist's impression (right) of Ultima Thule's appearance.
Color may seem trivial, but for the New Horizons team, it's critical information that will help the researchers determine what ices and minerals decorate the object's surface, says Silvia Protopapa, a co-investigator of the New HorizonsKuiper Belt Extended Mission.
We now know the basics of this odd object, the most distant solar system body ever explored by a spacecraft. The mission scientists believe that 4.5 billion years ago, a rotating cloud of small, icy bodies coalesced.
The two spheres spiralled closer to each other and eventually got stuck together.
He added: "These are the only remaining basic building blocks in the back yard of the solar system that we can see that everything else that we live on, or receive through our telescopes, or visit with our spacecraft, were formed from. We are seeing a physical representation of the beginning of planetary formation, frozen in time", Jeff Moore, New Horizons Geology and Geophysics team lead, said in a statement.
"You can see they're clearly two separate objects that have come together", said Cathy Olkin, the mission's deputy project scientist.
Before the new picture, the only image scientists had showed a peanut-shaped blur. Now, May has combined both of his loves on "New Horizons", his first solo song in more than two decades. This image was taken by the craft's Multispectral Visible Imaging Camera (MVIC), which combines light from the infrared, red and blue channels. The images, she said, also showed some brightness variations on the surface, including a brighter area in the neck where the two bodies meet.
The probe won't start sending back most of its Ultima Thule info until next week, when the sun stops blocking its transmissions to Earth.
The mission team has made a decision to call the larger lobe "Ultima" and the smaller lobe "Thule".
"This is the first object that we can clearly tell was born this way" Stern said, instead of evolving as a sort of "bi-lobe".
After it coasted through, NASA selected Ultima Thule as the next observational target and set a course.
New Horizons principal investigator Alan Stern (centre) of the Southwest Research Institute celebrates the breakthrough with other mission team members.