The cosmic body is farther from Earth than any other that's had a close encounter with a NASA probe, scientists believe.
Just hours before a historic rendezvous with Ultima Thule, the most distant object ever visited by a spacecraft, scientists with NASA's New Horizons mission are getting a first tantalizing glimpse of their target.
Previously, New Horizons swooped by Pluto in 2015, capturing the icy, mountainous world in unprecedented detail. Measurements taken Saturday showed that the spacecraft was within 20 miles of its intended flyby distance from Ultima Thule, and that the timing of the encounter will be within 2 seconds of what was expected.
Hurtling through space at a speed of 32,000 miles per hour, the spacecraft aims to make its closest approach within 2,200 miles of the surface of Ultima Thule. "This flyby is the culmination of years of careful planning and hard work, and we can't wait to transform Ultima into a real world".
On Monday, scientists at the Johns Hopkins Applied Physics Laboratory repeatedly underscored how little anyone still knows about Ultima Thule.
We do know that Ultima Thule has a reddish colour, probably caused by exposure of hydrocarbons to sunlight over billions of years.
"Young craters could provide a window to see the composition of the subsurface of Ultima Thule".
"We set a record".
USA citizen arrested in Moscow on suspicion of spying
Department of State confirmed that Moscow notified them of the alleged arrest, but did not confirm the arrest or the man's name. Chief Financial Officer Meng Wanzhou, who was arrested in Canada this month as part of a US extradition effort.
The Queen guitarist, 71, is releasing New Horizons, his first solo work in over two decades, as a "tribute" to the spacecraft of the same name. "We're a billion miles further than Pluto, and now we're going to keep going into the Kuiper Belt".
The encounter comes almost 50 years after Apollo 11 astronauts Neil Armstrong and Buzz Aldrin took the first steps on the moon in July 1969.
Ultima Thule - which means "beyond the known world" - is located in the Kuiper belt in the outermost regions of the solar system, beyond the orbit of Neptune.
The collected data on the Ground will continue through the fall of 2020.
NASA says the spacecraft's objective is to grab samples of gravel from the asteroid in 2020 and return them to Earth by 2023 - a manoeuvre described as a "gentle high-five".
It will take an estimated 10 hours for flight controllers to find out whether the spacecraft has survived the close encounter - and will find out if the pass was successful at about 3pm United Kingdom time. This is known as the Kuiper belt, and Pluto is considered to be the largest member, followed by Eris, Haumea, 2007 OR10, Makemake and Charon (Pluto's binary planet pair-bond, or its largest moon, whichever you prefer). As such, it is "probably the best time capsule we've ever had for understanding the birth of our solar system and the planets in it", Stern said.
John Spencer, from the Southwest Research Institute, added: "Now it is just a matter of time to see the data coming down".
According to a report in Digital Trends, NASA has already known that Ultima Thule's shape is not spherical, but that rather it boasts a kind of elongated shape, suggesting it could also be two objects which move close together. "We'll find out Tuesday".