New Horizons mission reveals entirely new kind of world

Studying it could offer insights to how Earth and the other planets formed.

The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, designed, built and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. "Objects in the universe are the same way... they're dynamic".

The first color image of Ultima Thule, taken at a distance of 85,000 miles (137,000 kilometers) at 4:08 Universal Time on January 1, 2019, highlights its reddish surface.

Early exploration of its topography also suggests the two lobes - the big one called Ultima, the small one named Thule - came together so slowly that if two cars in a parking lot collided at the same speed, "you wouldn't even fill out the insurance forms", New Horizons' geology and geophysics lead, Jeff Moore, said. But puzzling through the origins of the Solar System using only the final products, like our own Earth, is like trying to discern a recipe from a loaf of fully baked bread: numerous components have already been substantially, and often irreversibly, altered by heat and time. The best bet for sussing out the ingredients is sifting through the unbaked scraps left at the bottom of the mixing bowl-the basic building blocks from which the planets may have formed.

Ultima Thule measures around 31km long and 19km wide at its widest point, which is located on larger sphere "Ultima".

Ultima Thule is a tiny, icy body known as a Kuiper Belt Object (KBO). For example, comets that visit Earth from the Kuiper belt have had a peanutlike profile similar to MU69, prompting debate about whether they were sculpted by the sun's heat or looked that way from the start.

The mutual gravity of Ultima Thule's lobes appears to be holding the pair together, and scientists theorise that smaller objects have settled in the valley, or "neck", where the lobes meet, giving a brighter appearance. That's because the New Horizons spacecraft, which has now traveled some 4 billion miles through our Solar System, finally made its flyby of the most distant object ever studied up close. This "localized swarm", he says, created two separate orbs, each around 10 miles in diameter.

We also now know that Ultima Thule has a reddish/brown tint to its surface. It resembled something of a pixelated peanut, or a celestial bowling pin. But now, "that image is so 2018", Stern quipped during the press conference.

As the spacecraft transmits dozens more data sets to Earth, "we'll write new chapters in the story of Ultima Thule-and the Solar System", according to New Horizons Project Manager Helene Winters.

Moving forward, the team will continue analyzing evidence from the New Year's Day flyby; much higher resolution images are expected in the coming weeks and months.