In July 2017, Ultima Thule passed in front of a star as seen from Earth, allowing astronomers to determine that its shape is most likely a contact binary (two bodies that are touching) or a close binary system (two objects that are orbiting each other).
The Kuiper Belt object was discovered with the Hubble Space Telescope in 2014.
United States space probe New Horizons flew past 2014 MU69 Ultima Thule asteroid at the very edge of the solar system, making it the farthest from the Earth ever visited by a probe from our planet, NASA said on Tuesday.
"As you celebrate New Year's Day, cast an eye upward and think for a moment about the incredible things our country and our species can do when we set our minds to it", Stern wrote in the New York Times on Monday. 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 aimed to make its closest approach within 2,200 miles of the surface of Ultima Thule.
The Johns Hopkins University Applied Physics Laboratory, which built and operates the spacecraft, said Tuesday it had "zipped past" the object known as 2014 MU69, or Ultima Thule. Instead, hundreds of team members and their guests gathered nearby on campus for back-to-back countdowns.
The crowd ushered in 2019 at midnight, then cheered, blew party horns and jubilantly waved small U.S. flags again 33 minutes later, the appointed time for New Horizons' closest approach to Ultima Thule.
From that distance, Ultima Thule will appear as big as the full moon does in the sky here on Earth.
"We set a record".
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The New Horizons probe was slated to reach the "third zone" in the uncharted heart of the Kuiper Belt at around 9 am UAE time.
After closely studying the asteroid for several weeks, Osiris-Rex fired its thrusters to bring it into orbit around Bennu at 7.43pm United Kingdom time on New Year's Eve.
Project scientist Hal Weaver of the Johns Hopkins Applied Physics Laboratory said humans didn´t even know the Kuiper Belt - a vast ring of relics from the formation days of the solar system - existed until the 1990s.
The collected data on the Ground will continue through the fall of 2020. Detailed images won't be available immediately, as it takes around six hours for the data to arrive back on Earth.
"In the coming days New Horizons will go down in history!"
This is truly unlike any object we've explored, elsewhere in our solar system!
To the ancient Roman and Greeks, Ultima Thule was originally the most northerly part of the Earth, but the name was used to refer to anywhere which was outside the known world.
"We know it's not round", John Spencer, a New Horizons deputy project scientist, told reporters today (Mon, Dec 31).
Not long after the stroke of midnight on New Year's Day, as 2018 gave way to 2019, NASA's New Horizons spacecraft flew by the far-out space rock Ultima Thule.
"Who knows what we might find?". This time, however, the spacecraft will fly three times closer to the target than it did to Pluto.