A Giant Red Snowman in Space? New Horizons Returns First Color Images of Ultima Thule

The New Horizons spacecraft returned the first the first-ever pictures of Ultima Thule, the most distant object ever visited by a spacecraft, and it looks like a giant red snowman. The first images of that body have just been released to the public.

Ultima Thule lies in the Kuiper Belt, a collection of icy and rocky bodies beyond the orbit of Pluto. Researchers hope examination of the body will unravel mysteries of processes which formed our solar system more than four billion years ago.

“New Horizons is like a time machine, taking us back to the birth of the solar system. We are seeing a physical representation of the beginning of planetary formation, frozen in time. Studying Ultima Thule is helping us understand how planets form — both those in our own solar system and those orbiting other stars in our galaxy,” said Jeff Moore, lead investigator of the New Horizons Geology and Geophysics team.

Ultima Thule, the most distant object ever visited by a spacecraft, resembles a large red snowman.
Ultima Thule seen in color, in images taken by the New Horizons Spacecraft, January 1, 2019. The picture on the left shows color, without much detail. The middle picture brings out detail in black and white. The image on the right combines the two into the first color picture ever returned from this distant body.
Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The pair of bodies likely collided when the solar system was just one percent of its current age, at speeds around that of two cars in a fender-bender. Astronomers are calling the larger of the pair Ultima, and the smaller Thule. Ultima is approximately 19 km (12 miles) in diameter, and Thule stretches 14 km (nine miles) from side-to-side. The band where the two halves meet is lighter in color, although the reason for that is unclear.

Ultima Thule
This photo of Ultima Thule was taken just 30 minutes before closest approach, at a distance of 28,00 km (18,000 miles). Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Many comets form in the Kuiper Belt, and are nudged by collisions into orbits which bring them closer to the Sun. During the trip, they can heat up, ejecting material, which is pushed away from the body into tails that can (occasionally) be seen from Earth. Many comets have shapes similar to snowmen (or peanuts), leading astronomers to question whether they formed that way, or if the formation was an artifact of being heated by the Sun. This new observation suggests such objects can develop into that shape from collisions, without the influence of heating.

This idea also lends credence to the theory that the terrestrial planets in our solar system – Mercury, Venus, Earth, and Mars – formed through the collision of small pieces of rocky, a process known as pebble accretion.

To celebrate the occasion, Brian May, famous for his role as the guitarist for the band Queen, released a video of a song he wrote about the New Horizons mission. Following the death of lead singer Freddie Mercury in 1991, May concentrated on investigating and popularizing astrophysics and astronomy, and is currently highly-respected in the field.

New Horizons made history as the first spacecraft to visit Pluto, and now it is the first robotic explorer to examine an object in the Kuiper Belt. The vehicle passed within 28,000 km (18,000 miles) of the enigmatic object on New Year’s Day.

The New Horizons spacecraft took dozens of additional photos of Ultima Thule, which will be transmitted back to Earth during the next few weeks. Enjoy the science – and the music!

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