Tampa (AFP) – A NASA spaceship races toward a historic New Year's flyby of the remotest planetary object ever studied, a frozen relic of the early solar system called Ultima Thule.
Four billion miles (6.4 billion) kilometers away is the unmanned spacecraft New Horizons on January 1 at 12:33 (0533 GMT) at a distance of only 3,500 kilometers from Ultima Thule.
This is more than three times closer than New Horizons came to Pluto when he was taken by the dwarf planet in 2015.
What is this strange object named after a mythical, far north island in medieval literature and its own rock hymn by Queen guitarist Brian May?
"This is truly the most primitive object a spaceship has ever encountered," said Hal Weaver, a project scientist at the Johns Hopkins Applied Physics Laboratory.
Scientists are relatively small in its exact size.
But they are. Lieve is about 100 times smaller than Pluto, which has a diameter of nearly 2,400 kilometers.
Ultima Thule is also in an icy room, suggesting he can stay well.
"Really a remnant of the formation of the solar system," said Weaver.
– "Attic" of the Solar System –
Ultima Thule (pronounced TOO-Lee) lies in the Kuiper Belt, a vast cosmic disc left over when planets formed for the first time.
Astronomers sometimes call it the "attic" of the solar system.
Scientists did not even know that the Kuiper belt existed before the 1990s.
The Kuiper Belt begins at about three billion miles (4.8 billion kilometers) behind the Sun, past Neptune's orbit furthest from the Sun.
"There are literally billions of comets, millions of objects like Ultima, called planetsimals that make up planets, and a few – a handful of dwarf planets the size of a continent like Pluto," said Alan Stern, chief investigator at New Horizons.
"It is important to us in planetary science because this region of the solar system, which is so far from the Sun, preserves the original conditions four and a half billion years ago," added Stern.
"So, as we fly past Ultima, we'll be able to see how things were in the beginning."
– High Speed, Close Encounter –
The New Horizons spacecraft is racing Speed of 51,000 kilometers per hour through space, driving nearly one million miles per day.
At this rate, a piece of debris hits a small as a rice pellet, the spaceship could be destroyed immediately.
"We do not want that to happen," Stern said.
If New Horizon survives this flyby, it will do so while capturing hundreds of images from Ultima Thule, hoping to reveal its form and geology for the first time.  New Horizons sent stunning images of Pluto in 2015 – including a never before seen heart shape on its surface.
This time "we will try to play Ultima at the triple resolution we had for Pluto," Stern said.
But the flyby "requires extremely precise navigation, more accurate than ever, we could understand it, and maybe not," added Stern.
– Answers to come –
Ultima Thule was first discovered in 2014 by the Hubble Space Telescope.
Scientists discovered in 2017 that Ultima Thule is not spherical but may be elongated, it can even be two objects.
It does not project the repetitive, pulsating light that scientists expect from a spinning cosmic object and pose puzzling questions.
Could it be surrounded? cosmic dust? Wrapped in many tiny moons? Aligned so that its pole faces the approaching spaceship?
NASA hopes the flyby will reveal the answers.
The first pictures are expected on the evening of January 1st. Publication expected on 2 January.
More high-resolution images should follow.
Although no live images are possible at this distance, NASA plans to conduct online broadcasts during the flyby, with an animated video and music by Queen guitarist Brian May, who holds a degree in astrophysics and publishes one musical homage to accompany the event.
"I was inspired by the idea that this is the furthest one the Hand of Man has ever achieved," May said.
And Stern hopes this was won for New Horizons, which launched in 2006 and by Plutonium is driven, that's not the end.
"We hope to hunt another KPO (Kuiper Belt Object) and make an even more remote flyby in the 2020s," said Stern