Watch Tonight's New Horizon's Flyby of Ultima Thule Right Here

Christopher Davidson
January 2, 2019

At 12:33 am ET on New Year's morning, the spacecraft passed Ultima Thule, a Manhattan-sized rock a billion miles farther out and essentially straight ahead from its Pluto passage in 2015.

This composite image shows the Kuiper Belt object nicknamed Ultima Thule indicated by the crosshairs at center, with stars surrounding it on August 16, 2018, made by the New Horizons spacecraft.

Joining the celebrations of enthusiastic scientists was Brian May, who is a guitarist with rock band Queen and also an astrophysicist.

The live broadcast can be followed at

On the left, Ultima Thule is imaged by New Horizons at the start of December 2018, from a distance of 38.7 million kilometres.

Now a billion miles beyond Pluto, New Horizons will fly by Ultima just 2,200 miles (3,500 kilometers) from the object's surface, providing the first close-up look at what scientists consider to be one of the ancient building blocks of the planets.

"The object is in such a deep freeze that it is perfectly preserved from its original formation", he said.

It is the furthest exploration of any object in the Solar System.

Mission operations manager Alice Bowman added: "The spacecraft is healthy and we're excited!" By the time the first images and data stream back to Earth, the borders of the known world will have expand once more.

Scientists at NASA are celebrating after receiving messages from its New Horizons probe, 6.5 billion km away.

NASA announcement: New Horizons set for historic flyby TOMORROW
This explains why, in earlier images taken before Ultima was resolved, its brightness didn't appear to vary as it rotated. Seeing Ultima, then, is like witnessing our solar system origins, long before the first life even evolved on Earth.

What does it look like?

An image of Thule, sent overnight and barely more detailed than previous images, deepens the mystery of whether Thule is a single rock shaped like an asymmetrical peanut or actually two rocks orbiting each other, "blurred together due to their proximity", Stern said.

It was discovered in 2014 with the help of the Hubble Space Telescope, and is believed to be up to 32km in size. Even clearer images should arrive over the next three days.

Launched in January 2006, New Horizons embarked on a four billion mile journey toward the solar system's frigid edge to study the dwarf planet Pluto and its five moons. The highest-resolution images won't be received on Earth until February, but this week's data is expected to reveal the basic structure of Ultima.

"We know it's not round", John Spencer, a New Horizons deputy project scientist, told reporters today (Mon, Dec 31).

The flyby will be fast, at a speed of nine miles per second. "The exploration at Ultima Thule is a fitting way to honor the brash exploration and boldness that was Apollo", Stern wrote in an opinion piece in The New York Times. Although not the official name for MU69, the title Ultima Thule was selected from an online naming contest that translates to "beyond the known world".

Engineers at Johns Hopkins Applied Physics Laboratory in Maryland cheered when the spacecraft's first signals came through the National Aeronautic and Space Agency's Deep Space Network at (1528 GMT 11:28 p.m. Tuesday in Manila).

"This is the frontier of planetary science", said Weaver.

"We finally have reached the outskirts of the solar system, these things that have been there since the beginning and have hardly changed - we think". "What we'll very soon learn about this primordial building block of our solar system will exponentially expand our knowledge of this relatively unknown third region of space".

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