Gravity is a spherically symmetric force, so everything large enough to be held together by its own gravity is roundish.
So next season of Ancient Aliens Pluto will be the home of our ancestors?...But seriously this is really awesome
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New Horizons' Next Target Just Got a Lot More Interesting Could the next flyby target for NASA’s New Horizons spacecraft actually be two targets? New Horizons scientists look to answer that question as they sort through new data gathered on the distant Kuiper Belt object (KBO) 2014 MU69, which the spacecraft will fly past on Jan. 1, 2019. That flyby will be the most distant in the history of space exploration, a billion miles beyond Pluto. The ancient KBO, which is more than four billion miles (6.5 billion kilometers) from Earth, passed in front of a star on July 17. A handful of telescopes deployed by the New Horizons team in a remote part of Patagonia, Argentina, were in the right place at the right time to catch its fleeting shadow — an event known as an occultation – and were able to capture important data to help mission flyby planners better determine the spacecraft trajectory and understand the size, shape, orbit and environment around MU69. Based on these new occultation observations, team members say MU69 may not be not a lone spherical object, but suspect it could be an “extreme prolate spheroid” – think of a skinny football – or even a binary pair. The odd shape has scientists thinking two bodies may be orbiting very close together or even touching – what’s known as a close or contact binary – or perhaps they’re observing a single body with a large chunk taken out of it. The size of MU69 or its components also can be determined from these data. It appears to be no more than 20 miles (30 kilometers) long, or, if a binary, each about 9-12 miles (15-20 kilometers) in diameter. “This new finding is simply spectacular. The shape of MU69 is truly provocative, and could mean another first for New Horizons going to a binary object in the Kuiper Belt,” said Alan Stern, mission principal investigator from the Southwest Research Institute (SwRI) in Boulder, Colorado. “I could not be happier with the occultation results, which promise a scientific bonanza for the flyby.” The July 17 stellar occultation event that gathered these data was the third of a historic set of three ambitious occultation observations for New Horizons. The team used data from the Hubble Space Telescope and European Space Agency’s Gaia satellite to calculate and pinpoint where MU69 would cast a shadow on Earth's surface. “Both of these space satellites were crucial to the success of the entire occultation campaign,” added Stern. Said Marc Buie, the New Horizons co-investigator from SwRI who led the observation campaign, "These exciting and puzzling results have already been key for our mission planning, but also add to the mysteries surrounding this target leading into the New Horizons encounter with MU69, now less than 17 months away.” jhuapl.edu
NASA’s New Horizons Spacecraft Captures Its First Photo of Ultima Thule, Its Next Target Though it’s still 107 million miles from its target, the New Horizons spacecraft has caught a first glimpse of Ultima Thule, a mysterious Kuiper Belt object. With Pluto now firmly in its rearview mirror, NASA’s New Horizons spacecraft is steadily chugging towards Ultima Thule, a Kuiper Belt object located, on average, about 44 AU from the Sun (one AU is the average distance of the Earth to the Sun). By comparison, Pluto’s orbit is around 33.63 AU. On August 16, and at a distance of 107 million miles from Ultima Thule, New Horizons used its telescopic Long Range Reconnaissance Imager (LORRI) to snap four dozen images. The data was transmitted back to Earth, where NASA scientists, to their delight, managed to create a composite image and discern the dim object from all the background noise produced by stars. Happily, the location of Ultimate Thule, or (486958) 2014 MU69 as it’s officially known, was exactly where NASA scientists had predicted. That means New Horizons is right on track. “The image field is extremely rich with background stars, which makes it difficult to detect faint objects,” Hal Weaver, a New Horizons project scientist and LORRI principal investigator, said in a statement. “It really is like finding a needle in a haystack. In these first images, Ultima appears only as a bump on the side of a background star that’s roughly 17 times brighter, but Ultima will be getting brighter—and easier to see—as the spacecraft gets closer.” This picture is significant for several reasons. First and foremost, it’s super cool—it’s an actual photograph of a 19-mile-wide (30-kilometer) object located 4 billion miles (6.5 billion kilometers) from Earth. Secondly, these images are now the most distant ever taken from Earth (New Horizons just broke its own record). And lastly, New Horizons proved that it’s now able to visually detect its target, which means mission planners can adjust the spacecraft’s trajectory if needed. According to NASA’s itinerary, New Horizons will zoom past Ultima Thule on January 1, 2019 (yep, New Year’s Day) at 12:33 a.m. EST. (It boggles the mind to think that, after traveling for billions of miles, NASA knows its its arrival time down to the minute. I only wish my own navigation skills were that accurate.)
Reading about these chance discoveries...Imagine the day we use machine learning to map the skies instead of just astronomers. Would be like putting on glasses for the first time.
NASA spacecraft hurtles toward historic New Year's flyby A NASA spacecraft is hurtling toward a historic New Year's Day flyby of the most distant planetary object ever studied, a frozen relic of the early solar system called Ultima Thule. Four billion miles (6.4 billion kilometers) away, the unmanned spaceship, New Horizons, is poised to zoom by at 12:33 am (0533 GMT) on January 1, at a distance of just 2,200 miles (3,500 kilometers) from Ultima Thule. That's more than three times closer than New Horizons came to Pluto when it zipped by the dwarf planet in 2015. So what is this strange object, which is named after a mythical, far-northern island in medieval literature and has its own rock anthem performed by Queen guitarist Brian May? "This is truly the most primitive object ever encountered by a spacecraft," said Hal Weaver, project scientist at the Johns Hopkins Applied Physics Laboratory. Relatively small, scientists aren't sure about its exact size. But they believe it is about 100 times tinier than Pluto which measures almost 1,500 miles (2,414 kilometers) in diameter. Ultima Thule is also in a freezing area of space, suggesting it may remain well preserved. "Really, it is a relic from the formation of the solar system," said Weaver. 'Attic' of the solar system Ultima Thule (pronounced TOO-lee) lies in the Kuiper Belt, a vast cosmic disc left over from the days when planets first formed. Astronomers sometimes call it the "attic" of the solar system. Scientists didn't even know the Kuiper Belt existed until the 1990s. The Kuiper Belt begins some three billion miles (4.8 billion kilometers) beyond the Sun, past the orbit of Neptune which is the furthest planet from the Sun. "It is teeming with literally billions of comets, millions of objects like Ultima which are called planetesimals, the building blocks out of which planets were formed, and a smattering—a handful of dwarf planets the size of continents, like Pluto," said Alan Stern, principal investigator on New Horizons. "It is important to us in planetary science because this region of the solar system, being so far from the Sun, preserves the original conditions from four and a half billion years ago," Stern added. "So when we fly by Ultima, we are going to be able to see the way things were back at the beginning." High-speed, close encounter The New Horizons spacecraft is speeding through space at 32,000 miles (51,500 kilometers) per hour, traveling almost a million miles per day. At that pace, if it strikes a piece of debris as small as a rice pellet, the spacecraft could be destroyed instantly. "We don't want that to happen," said Stern. If New Horizon survives this flyby, it will do so while furiously snapping hundreds of pictures of Ultima Thule, in the hopes of revealing its shape and geology for the first time. New Horizons sent back stunning images of Pluto—including a never before seen heart shape on its surface—in 2015. This time, "at closest approach we are going to try to image Ultima at three times the resolution we had for Pluto," Stern said. But the flyby "requires extremely precise navigation. Much more precise than we have ever tried before. We might get it, and we might not," Stern added. Answers to come? Ultima Thule was first discovered by the Hubble Space Telescope in 2014. Scientists figured out in 2017 that Ultima Thule is not spherical but possibly elongated in shape. It may even be two objects. It does not project the repeated, pulsing light scientists expect to see from a rotating cosmic object, raising puzzling questions. Could it be surrounded by cosmic dust? Enveloped by many tiny moons? Oriented in such a way that its pole is facing the approaching spacecraft? NASA hopes the flyby will reveal the answers. The first images are expected by the evening of January 1, with release planned for January 2. More, higher resolution shots should follow. Though no live images are possible at this distance, NASA plans to broadcast online during the flyby, featuring an animated video and music by Queen guitarist Brian May, who holds a degree in astrophysics and is releasing a musical tribute to accompany the event. "I was inspired by the idea that this is the furthest that the Hand of Man has ever reached," May said. And Stern hopes this won't be the end for New Horizons, which launched in 2006 and is powered by plutonium. "We hope to hunt down one more KPO (Kuiper Belt Object), making an even more distant flyby in the 2020s," Stern said. https://phys.org/news/2018-12-nasa-spacecraft-hurtles-historic-year.amp
