2014 MU69

Ultima Thule (nickname)


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    March 18, 2019: The farthest object ever explored up close is slowly revealing its secrets, as scientists piece together the puzzles of 2014 MU69–the Kuiper Belt object NASA's New Horizons spacecraft flew past on New Year's Day, four billion miles from Earth.

    two frames showing object from two slightly different angles
    This brief animation "flickers" between New Horizons spacecraft views of Ultima Thule, the spacecraft's New Year's 2019 flyby target in the Kuiper Belt. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/National Optical

    Analyzing the data New Horizons has been sending home since the flyby, mission scientists are learning more about the development, geology and composition of this ancient relic of solar system formation. At 22 miles (35 kilometers) long, MU69 consists of a large, flat lobe (nicknamed "Ultima") connected to a smaller, rounder lobe (nicknamed "Thule").

    This strange shape is the biggest surprise, so far, of the flyby. "We've never seen anything like this anywhere in the solar system," said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colorado. "It is sending the planetary science community back to the drawing board to understand how planetesimals–the building blocks of the planets–form."

    Read more about the latest findings


    Billions of miles away, you can find some of the best-preserved fossils of the beginnings of our solar system. 2014 MU69, also known as Ultima Thule, is one of those relics that has been in a deep freeze all this time, with its orbit virtually unchanged over 4.5 billion years. Circling the Sun in a distant region of icy, rocky bodies called the Kuiper Belt, MU69 may represent the building blocks of Pluto and other planet-like worlds beyond Neptune.

    10 Things to Know About MU69

    10 Things to Know About 2014 MU69


    Discovered in 2014

    NASA’s Hubble Space Telescope pinpointed MU69 on June 26, 2014.



    About 40 people suggested the nickname Ultima Thule, and the
    New Horizons team chose it.



    Ultima Thule’s name signifies “beyond the borders of the known world.”

    Artist's Concept (Binary)


    Very Far

    MU69 is about 4.1 billion miles (6.6 billion kilometers) from Earth.


    Long Way Round

    It takes about 296 Earth years for MU69 to make one trip around the Sun. 


    Might be Two Objects

    1. MU69 may turn out to be two objects orbiting each other or even touching.



    If MU69 is a single object, it is seems to shaped like a typical baking potato.


    New Name

    The New Horizons team will recommend a formal name after the 2019 flyby, and determining whether it is one object or two.


    A True Relic

    This small world's orbit may have been virtually unchanged since the dawn of the solar system.


    Happy New Year

    New Horizons will fly by MU69 on Jan. 1, 2019 (UTC).

    Artist's Concept (Single)


    Very Far

    MU69 is about 4.1 billion miles (6.6 billion kilometers) from Earth.

    Did You Know?

    Did You Know?

    NASA’s New Horizons team picked the nickname Ultima Thule in homage to a far-northern island in medieval literature and cartography.

    New Horizons will be the first mission to visit an object that was discovered after the spacecraft launched.

    MU69 is the most distant object explored to date.

    Additional Resources

    Additional Resources

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