NASA's New Horizons mission team has published the first profile of the world's foremost exploration, a planetary building block and Kuiper Belt object called 2014 MU69. 19659004] Analyzing just the first sets of data gathered during the New Horizons spacecraft's New Year's 2019 flyby of MU69 (nicknamed Ultima Thule), the mission team quickly discovered a more complex complex than expected. The team publishes the first peer-reviewed scientific results and interpretations – just four months after the flyby – in the May 17 issue of the journal Science.
In addition to being the farthest exploration of an object in history – four billion miles from Earth – the flyby of Ultima Thule was also the first investigation by any space mission of a well-preserved planettesimal, an ancient relic from the era of planet formation.
and composition. It's a contact binary, with two distinctly differently shaped lobes. At about 22 miles (36 kilometers) long, Ultima Thule consists of a large, strangely flat lobe (nicknamed "Ultima") connected to a smaller, somewhat rounder lobe (nicknamed "Thule"), at a juncture nicknamed "the neck. (19659004) The lobes probably once orbited each other, like many so-called binary worlds in the Kuiper Belt, until some process brought them together in what scientists have shown to be a "gentle" merger. For that to happen, much of the binary's orbital momentum must have dissipated for the objects to come together, but scientists still do not know whether that was due to aerodynamic forces from the gas in the ancient solar nebula, or if Ultima and Thule ejected other lobes that formed with them to dissipate energy and shrink their orbit. The alignment of the axes of Ultima and Thule indicates that prior to the merger, the two lobes must have become tidally locked, meaning that the same sides always face each other as they are orbited around the same point
"We're looking into the well-preserved remnants of the ancient past, "said New Horizons Principal Investigator, Alan Stern, of the Southwest Research Institute, Boulder, Colorado. "There is no doubt that the discoveries made about Ultima Thule are going to advance theories of solar system formation."
As the science paper reports, New Horizons researchers are also investigating a range of surface features on Ultima Thule, such as bright spots and patches, hills and troughs, and craters and pits on Ultima Thule. The largest depression is a 5-mile-wide feature, the team has a nicknamed Maryland crater – which probably formed from an impact. Some smaller pits on the Kuiper Belt object, however, may have been created by material falling into underground spaces, or due to exotic ices going from a solid to a gas (called sublimation) and leaving pits in its place
In color and composition, Ultima Thule resembles many other objects found in its area of the Kuiper Belt. It is very red – redder even than much larger, 2,400-kilometer wide Pluto which New Horizons explored at the inner edge of the Kuiper Belt in 2015 – and is in fact the reddest outer solar system object ever visited by spacecraft; its new red horizons are believed to be caused by modification of organic materials on its surface New Horizons scientists found evidence for methanol, water ice, and organic molecules on Ultima Thule's surface – a mixture very different from most ice objects previously explored by spacecraft. 19659004] Data transmission from the flyby continues, and will continue until late summer 2020. Meanwhile, New Horizons continues to carry out new observations of additional Kuiper Belt objects that passes in the distance. These additional KBOs are too distant to reveal discoveries like those on MU69, but the team can measure aspects such as the object's brightness. The New Horizons Spacecraft is now 4,1 billion miles (6.6 billion kilometers) from Earth, operating normally and speeding deep into the Kuiper Belt at nearly
The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. The MSFC Planetary Management Office provides NASA oversight for the New Horizons. The Southwest Research Institute, based in San Antonio, directs the mission through Principal Investigator Stern and leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama.
Publication: SA Stern, et al., "Initial results from the New Horizons exploration of 2014 MU 69 and a small Kuiper Belt object, "Science 17 May 2019: Vol. 364, Issue 6441, eaaw9771; DOI: 10.1126 / science.aaw9771