Kuiper Belt Concepts

How I Killed Pluto and Why It Had It Coming

by Mike Brown · 7 Dec 2010 · 242pp · 81,209 words

out across the water in the same direction I was staring. Softly and conspiratorially she said, “Nobody knows it yet, but we just found the Kuiper belt.” I could tell that she knew she was onto something big, could sense her excitement, and I was flattered that here she was telling me

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building a day before it appeared on the front page of The New York Times. But when Jane told me she had just found the Kuiper belt, I didn’t know any of this. Jane explained. She had not found this vast collection of bodies beyond Neptune, exactly, but simply a

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solar system, but it turned out that it had more company than astronomers had originally thought. Over the years since I had dismissed the entire Kuiper belt as not quite interesting enough to pull my mind away from Jupiter, I had actually been thinking a bit about Pluto and about those five

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sky for a new planet since the 1930s, when Pluto itself was found, and even though astronomers knew of almost five hundred bodies in the Kuiper belt, the searches had been, of necessity, piecemeal, and no one had yet mounted a careful search like the one that had uncovered Pluto. Now,

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Jane Luu joined me on the roof overlooking the San Francisco Bay at the Berkeley astronomy department in 1992 was that the discovery of the Kuiper belt gave Pluto a context. It took me and most other astronomers a few more years to realize that Pluto is neither lonely nor an oddball

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, but rather part of this vast new population called the Kuiper belt. Just as the explosion of asteroid discoveries 150 years earlier had forced astronomers to reconsider the status of Ceres, Pallas, Juno, and Vesta and

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change them from full-fledged planets to simply the largest of the collection of asteroids, the new discovery of the Kuiper belt would certainly force astronomers to reconsider the status of Pluto. It was becoming more and more clear that if the asteroids were the schools of

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minnows swimming among the pod of whales, then Pluto and the Kuiper belt objects were simply a previously overlooked collection of sardines swimming in a faraway sea. If Ceres was to be thought of as just the largest

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with all their capabilities and thought and stared. It had been five years since that afternoon when Jane Luu had first told me about the Kuiper belt, and by this point almost a hundred small bodies were known in distant orbits beyond Neptune. It was becoming increasingly clear that the study of

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I set out to test one of the hypotheses that was floating around in the scientific community at that time: that the objects in the Kuiper belt have mottled surfaces owing to the effects of craters formed by giant impacts, just like those that I could see on the moon. Proving or

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To test the hypothesis, I was going to spend three nights at the 200-inch Hale Telescope carefully studying a few objects out in the Kuiper belt to see if their surfaces were indeed mottled. The three nights I was scheduled to be at the telescope happened to fall over Thanksgiving, a

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thought about the biggest fish. I had already been thinking by this time that Pluto might not be a solitary planet out there in the Kuiper belt; there might be others still to be found. And using the Schmidt was clearly the way to find them. There was a major problem,

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that doesn’t sound like much, in just a single month we were going to have covered more sky than all other astronomers searching for Kuiper belt objects had covered in the preceding five years. On a typical night, we would try to cover three or four fields. To do so,

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in red light, which doesn’t affect it. But these photographic plates were designed to be especially sensitive to red light, as objects in the Kuiper belt tend to be on the red side. All of the work on the plates, then, had to be done with no lights whatsoever. When

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grounds, and we had trawled it all. Looking at vastly more sky than anyone else had ever looked at for large objects out in the Kuiper belt was so immensely exciting that I could hardly contain myself. I knew that there would be big discoveries, and having new pictures come in night

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things immediately that I decided I needed help. I recruited Chad Trujillo, who was just finishing his doctoral thesis—on, conveniently, finding objects in the Kuiper belt—at the University of Hawaii. I wasn’t sure I was going to be able to convince him to come to Pasadena. He was so

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across the hall into my office and showed me that first discovery. Yes, it was somewhat small—larger things had been stumbled upon in the Kuiper belt already—but we now knew for certain that if we could find this relatively small chunk of ice so quickly, any planets hiding out there

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almost perfect but slightly askew orbit? Today we still don’t know the answer. We have elaborate theories of how the objects out in the Kuiper belt have been tossed around in their orbits by the giant planets, but all of this tossing both tilts and elongates the orbits. Tilted but circular

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’s surface, since it is one of the main components of the surface of Pluto, but it had never been seen anywhere else in the Kuiper belt, and the signature of methane was not overwhelmingly convincing. If methane was there at all, it was in extremely small amounts. A few years

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for why Titan and Pluto both had methane. Her final explanation was deceptively simple and explained not just these objects but the rest of the Kuiper belt as well. Object X, it turned out, formed with methane—as did Pluto and Titan—but Object X was just a little too small,

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Craters on Mercury have to be named for deceased poets; moon of Uranus are named for Shakespearean characters. For this type of object in the Kuiper belt, the rules said that the name had to be a creation deity in a mythology. After some quick thought, Chad and I decided that we

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. Chad said something like, “Hi, I’m an astronomer from Caltech, and we just discovered something big in this region of space called the Kuiper belt and were hoping to name it after a Tongva creation myth and wanted to talk to you about it,” at which point the chief probably

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Alabama, just two hours from my hometown, and we decided to make the announcement there. Chad submitted a paper with the innocuous-sounding title “Large Kuiper Belt Objects.” In his talk, he discussed everything that we had learned: Quaoar’s oddly circular yet inclined orbit, its diameter about half the size of

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thing: what did this discovery mean for whether or not Pluto was a planet? What, indeed? Even as more and more objects in the Kuiper belt were being found, Pluto still stood out as being significantly larger than any of the rest—but it was larger than Quaoar by only a

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throwing away only 10 percent of the haystack. On one of those late nights when I was sorting through recent data, I found a bright Kuiper belt object; and then five minutes later, one more; and then five minutes later, a third. Again, they were not the biggest or the brightest

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distance from the earth to the sun—would be more than three times the distance of Pluto and well beyond anything ever found in the Kuiper belt. Chad wrote back almost immediately: If that one is real I’ll be buying the champagne. Chad and I eventually drank that champagne. We

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strong enough slingshot to propel something out of the solar system, so when it tries, the objects always come back. Many objects in the Kuiper belt thus have orbits that take them close to the orbit of Neptune but then much, much farther away from the sun. These objects have been

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called “scattered” Kuiper belt objects, as Neptune appears to have scattered them to those looping orbits. Only small things get scattered. The large planets are on nice circular orbits

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distant point in its scattered orbit and would soon be making its way back toward the sun to show that it really belonged to the Kuiper belt region. Its orbit would be a clue to its potential planethood. As we had with Quaoar before, we eagerly looked for pictures of Dutch

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times farther away. Nothing was supposed to act like this in the solar system. It was neither a normal-seeming planet nor a normal scattered Kuiper belt object. There was nothing like it known anywhere else in the universe. It’s sometimes hard to picture all of these orbits and what they

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think that at one moment early in the history of the solar system, a much larger Haumea was smashed by another icy object in the Kuiper belt traveling at something like ten thousand miles per hour. Luckily for Haumea and for astronomers today, the impact was only a glancing blow. Had

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than Pluto. None of this was obvious when Santa/Haumea was first discovered. It just looked like a normal, albeit extra-bright, object in the Kuiper belt. David was the first to notice something strange: It got brighter and fainter every two hours, a fact that he quickly surmised was due to

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, is that the sunlight bouncing off Xena contained within it the unmistakable signature of a surface covered in solid frozen methane. Nothing else in the Kuiper belt looked like this, with one exception: Pluto. It was one thing to make the quick calculation to know that Xena was bigger than Pluto.

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them both planets?” I went over my usual litany: Pluto was simply the largest—now the second largest!—member of a huge population in the Kuiper belt. Singling it out for special planetary status really made no sense at all. “Okay, but think about your daughter.” Huh? “Having her father discover

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wanted to know about Santa, which he called K40506A, the name my computer program had automatically assigned it on the day of discovery (K for Kuiper belt, 40506 for 2004, May 6, and A for the first one found that day). A colleague across the country was interested in studying K40506A, and

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by David and one by Chad, each talking about something that they called K40506A and which they declared to be the brightest object in the Kuiper belt. I, being on family leave, had no intention of attending any conferences anytime soon, but I was nonetheless listed as a coauthor on both

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seen the announcement and were already starting to take notice. They wanted comments from the guy who usually found these large objects out in the Kuiper belt, and they wanted to know how someone had beaten me to it. Diane woke up and came in the room, and I told her

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I sent one more e-mail to Ortiz: Jose— Along with 2003 EL61, which you discovered this week, we have also been tracking two larger Kuiper belt objects. After the 2003 EL61 announcement someone tapped into an online database to see where we had been pointing our telescopes and, in doing so

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, reconstructed the positions of these two other Kuiper belt objects. They have now made these positions public. Because of all of this, we have had to announce these discoveries this morning. I am

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Xena, and Easterbunny. One particularly nice feature of that telescope in Chile was that for routine observations, like taking pictures of the positions of our Kuiper belt object, we didn’t have to fly to Chile each time we wanted a picture, but instead a person permanently stationed in Chile would take

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is the story as I envision it. I think that Ortiz and Santos-Sanz really were engaged in a legitimate search for objects in the Kuiper belt, even though they had not yet been successful. My guess is that they had never gotten around to writing the computer software to help

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amateur astronomers who are familiar with comet and near-earth asteroid observation protocols. We can only assume that this familiarity led them to their misconceptions. Kuiper belt objects are not quickly changing phenomena. Astronomers will be intensively studying Xena for a long time to come. We hope to discover a few more

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faster than new creation gods, the rule began to be applied more and more loosely. Recently someone even got away with calling something in the Kuiper belt Borasisi, which is a god from a fictional story by Kurt Vonnegut. For all of its preparedness for endless contingencies and countercontingencies, the IAU had

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.” It was a new definition by simple fiat. And it would lead to something like two hundred new planets, most of them out in the Kuiper belt. I explained all of this to the person writing the press releases. “Why bother writing this one up? It sounds crazy. No one would

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the mocking. Six days later, still on crutches, I headed to Italy to give a talk at an international conference on the Kuiper belt. We talked about the formation of the Kuiper belt, the surfaces and atmospheres of the objects there, and what they might be made of, but the question of what to

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. No one was going to let Pluto be killed, were they? But still, it was interesting. Within the field of people who studied the Kuiper belt for a living—people who had devoted their careers to the outer solar system and its many, many denizens—it was almost not worth having

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its own estimate and come up with its own number: twelve. Why would Charon and the asteroid Ceres be added, but not the dozen known Kuiper belt objects that were larger than Ceres? And the hundreds that were smaller but almost certainly round? It was as if the International Arboreal Union were

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8. Resolution 5B implies at least 11 and soon several dozen. Both Pluto and Ceres become planets, and probably several main belt asteroids and several Kuiper belt objects as well. Resolution 5B not only removes a fundamental dynamical distinction for a planet, it is confusing and internally inconsistent. In my view it

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wrong with our current classification of the solar system as a collection of eight planets and then a swarm of asteroids and a swarm of Kuiper belt objects is that it ignores the fundamental distinction between the terrestrial planets—Mercury, Venus, Earth, Mars—and the giant planets—Jupiter, Saturn, Uranus, Neptune.

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a place consisting of eight planets—or, better, four terrestrial planets and four giant planets—and then a swarm of asteroids and a swarm of Kuiper belt objects, you have a profound description of the local universe around us. Understanding how such a solar system came to be is one of the

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as a way of getting things restarted. Ah, Easterbunny. I had been thinking about it now for years. The names Sedna and Orcus (another large Kuiper belt object that we had turned up) had fit the characteristics of the objects’ orbits, and the names Eris and Haumea had practically fallen out of

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of the island of Rapa Nui. Rapa Nui was first visited by Europeans on Easter Sunday, 1722, precisely 283 years before the discovery of the Kuiper belt object now known as Makemake. Because of this first visit, the island is known in Spanish (it is a territory of Chile) as Isla

Chasing New Horizons: Inside the Epic First Mission to Pluto

by Alan Stern and David Grinspoon · 2 May 2018 · 323pp · 94,156 words

Kuiper and others had, Pluto was not just an oddball outlier but our first glimpse of what would later come to be known as the Kuiper Belt. In 1991, Alan took this idea further, publishing a research paper called “On the Number of Planets in the Outer Solar System: Evidence of

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and its vast cohort lie. By the time of Voyager 2’s Neptune encounter, Earthbound telescopes and detectors had improved to the point that such “Kuiper Belt Objects” (KBOs), if they were indeed there, could in principle be detected. It took a few years of searching, but the new tools of

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discovered. Ultimately in the 1990s, more than a thousand KBOs were found, distributed in the wide zone beyond Neptune that came to be called the Kuiper Belt. Most were small, perhaps the size of just counties, but others were much larger, and a handful even rivaled Pluto in size—the size of

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ones. Fran Bagenal recollects how these discoveries added fuel to the fire for a Pluto mission: Interest just exploded once we started to see the Kuiper Belt Objects. It was as if it had just been a bunch of Pluto people who were interested in this lone, fascinating object at the edge

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go and explore them. What’s out there?” I realized that he was right, and it got me really fired up. The discovery of the Kuiper Belt provided the additional scientific motivation to raise the priority of Pluto exploration back to the top. To emphasize that their hoped-for mission was now

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PKE, and to prepare for issuing a call for the mission’s scientific instrument proposals, Huntress formed a Science Definition Team (SDT) of Pluto and Kuiper Belt experts. The SDT was charged with defining formal goals for a Pluto mission and basic specifications for the instruments it would carry to achieve these

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team included Alan and many old members of the Pluto Underground and OPSWG, and also new faces who were experts in the science of the Kuiper Belt. Lunine’s SDT worked for almost a year to craft a tight mission rationale, a list of necessary and nice-to-have scientific instruments,

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many different everythings had we put up with? Big missions, little missions, micro-missions, Russian missions, German missions, nonnuclear missions, Pluto-only missions, Pluto-plus-Kuiper-Belt missions, and more; Weiler’s move just threw it all away. It was the end. He’d killed it. It felt like we’d survived

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.” Names came and went: dull, forgotten acronyms like COPE, ELOPE, POPE, and PFM. Some slightly better ones came in, such as PEAK (“Pluto Exploration And Kuiper-Belt”), or APEX (for “Advanced Pluto EXploration”). But none was particularly inspiring, strong, sufficiently catchy, or memorable. Along the way, Alan’s team learned that one

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and it just hit me. We could call it “New Horizons”—for we were seeking new horizons to explore at Pluto and Charon and the Kuiper Belt, and we were pioneering new horizons in how to run the first-ever PI-led outer-planets mission. Nobody, I thought, could find a black

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review process took two months. When the announcement of NASA’s down-select decision came, Alan was in Paris, at an international Kuiper Belt meeting. Many in the Pluto/Kuiper Belt community were there and knew that the announcement was imminent. Near midnight on the evening of June 6, Alan got back to his

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concept study report, “New Horizons: Shedding Light on Frontier Worlds,” submitted in response to the awarding of a Phase A study contract for the Pluto-Kuiper Belt (PKB) mission, has been selected to proceed. If only the letter had stopped there. But as Alan kept reading, his smile straightened and then was

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Horizons in 2002 and early 2003, they also had to wage an intensive campaign to make the case why the exploration of Pluto and the Kuiper Belt should be the very highest priority of the Decadal Survey. Project members spoke to individual members of the Decadal Survey, wrote scientific white papers for

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seemingly endless era of studies, funding battles, and politics. Ahead was a spaceflight project—building, launching, and flying New Horizons to explore Pluto and the Kuiper Belt—the final planetary frontier of our solar system. ALABAMA After the Decadal Survey battle was won and after killing off Weiler’s cumbersome solar electric

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been part of the original Pluto Underground. His background was instead primarily in the study of comets. But Hal had long been fascinated with the Kuiper Belt as the region of the solar system where certain comets originate. He had known Alan since the 1980s and they had collaborated together on some

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be safer. So, late on the night of September 24, the world’s first and only spacecraft charged with the exploration of Pluto and the Kuiper Belt was flown from Andrews Air Force Base outside Washington, DC, to NASA’s Kennedy Space Center launch site at Cape Canaveral. Alan and Glen and

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for their baby to take flight after so many years of hard work proposing and building and planning for its journey to Pluto and the Kuiper Belt. Science team geology and geophysics team lead Jeff Moore was there with his daughter and his mom. Geologist Paul Schenk was with his husband,

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them a bonus to put in their pocket, either for an asteroid flyby in June, or for more Kuiper Belt exploration after Pluto. Alan chose the bird in the bush—saving the fuel for the Kuiper Belt, a mission objective—which an asteroid flyby, though soon and seductive, was not. To fine-tune the

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Astronomical Union (or IAU) was held in Prague. At that meeting the definition of the word “planet” came up for a series of votes. The Kuiper Belt was turning out to be full of small icy planets that were much like Pluto and were neither gas giants like Jupiter, ice giants like

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discovered around distant stars in coming years. Many planetary scientists had long been referring to the rich harvest of newly discovered small planets in the Kuiper Belt as “dwarf planets,” a term Alan coined in a 1991 research paper mathematically calculating that the solar system might contain as many as one thousand

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“dwarf stars,” like the Sun, that are the most common type of stars in the universe. Then, in 2005, the discovery was reported of a Kuiper Belt planet later named Eris that was thought by its discoverer, Caltech scientist Mike Brown, to be slightly larger than Pluto (later this turned out to

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gravity to make round but not so massive that it ignites in nuclear fusion to become a star. In this scheme, dwarf planets in the Kuiper Belt were recognized as a new class of small planets in line with what many planetary scientists thought. But what happened next was more than just

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on, taking data while in hibernation so they could trace out the solar system’s dust and charged-particle environment all the way to the Kuiper Belt, a scientific bonanza en route to Pluto. 11 BATTLE PLAN PLUTO PLANNING THE INVASION Early in 2008, project manager Glen Fountain laid out a Pluto

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had originally targeted at Jupiter flyby, which was a bonus because Alan also wanted to save fuel for flybys of bodies farther out in the Kuiper Belt after Pluto. After settling on July 14 as the encounter date, Leslie’s team then began looking at flyby closest-approach distances. The most

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APPROACH HUNTING FOR STILL FURTHER DESTINATIONS As the Pluto flyby approached, the New Horizons team intensified a search it began in 2011 to find a Kuiper Belt Object that the spacecraft could intercept and study after Pluto. This opportunity to study ancient bodies beyond Pluto—particularly small ones that were the building

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blocks of small planets like Pluto—was a key part of the Decadal Survey’s motivation for its top endorsement of a Pluto Kuiper Belt mission back in 2003. By 2013, John Spencer and Marc Buie, who were leading the search for this flyby target using the world’s

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time it needed, with John leading the effort. Their proposal was turned down. They were incredulous. The Decadal Survey had directed New Horizons to study Kuiper Belt Objects. Only Hubble could enable the New Horizons mission to undertake this study. Would NASA allow them to fail to have a

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Kuiper Belt mission after Pluto for want of a couple of weeks of Hubble time, 2 percent of Hubble’s efforts that year? After all, there was

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in the next several decades, except with New Horizons—and if they didn’t get Hubble time, their mission was not going to have a Kuiper Belt flyby target. Alan appealed to NASA Headquarters, and after a second John Spencer proposal to the Hubble project in the spring of 2014 and some

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s your greatest concern?” There was also great interest in the finer details of the flyby mechanics, the team members’ personalities, the science of the Kuiper Belt, and much more. Nothing like this—the first exploration of a new planet—had occurred in a generation, and the media picked up on the

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a major organizing principle of their lives—some, for half or more of their careers. Now, each day, in images beamed to Earth from the Kuiper Belt, Pluto was growing in size. And it would continue to grow, day by day, until, in almost no time at all, it would be

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a half just watching and making occasional small talk while the flight controllers sent the command load from Earth out toward New Horizons in the Kuiper Belt. He thought a lot about all the years it had taken to make this happen, how much was riding on the successful operation of

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predicted. Alan then took pleasure in pointing out that this meant Pluto was, after all, larger than any other of the small planets in the Kuiper Belt, laying to rest the hope by some that dwarf planet Eris was larger than Pluto. As to those hoping Pluto was the second-largest body

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in the Kuiper Belt, Alan declared to the combined in-person and broadcast audience, “Well, now we can dispose of that.” Then the program was opened up to

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for—a scientific treasure trove of data that would revolutionize knowledge about Pluto, its moons, and the nature of all the small planets in the Kuiper Belt. A BONFIRE IN MARYLAND New Horizons was speeding away from Pluto, but its work was far from finished. Just about the time NASA Administrator Bolden

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system, New Horizons was approved by NASA for a five-year, extended mission to study other bodies in the Kuiper Belt. The centerpiece of that mission will be the flyby of an ancient Kuiper Belt Object (KBO) that represents the building blocks of small planets like Pluto. (The flyby’s target is one

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its flyby of Pluto. In addition to mapping MU69, studying its composition, and searching for moons and any atmosphere, as it travels outward through the Kuiper Belt, New Horizons will also study another two dozen or more KBOs from afar using its LORRI telescope/imager. Those studies will be used to search

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in better context. During this extended mission, New Horizons will also be used to conduct a five-year-long study of the environment in the Kuiper Belt by continuously monitoring the charged particles and dust there as it crosses out to a distance of fifty times as far from the Sun as

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the Pluto system in more depth will one day be funded. In addition, we think it’s likely that the other small planets of the Kuiper Belt will also likely be explored by spacecraft later in this century. If we humans are nothing else, we are an inquisitive and restless species, explorers

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at heart. For that reason, we’re also optimistic that even humans will one day travel to the Kuiper Belt to explore it in person, making footfall on Pluto and other Kuiper Belt worlds, as we have already done on the Moon and will soon do on Mars, and then no doubt on

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volcanoes, glaciers, evidence for flowing (and even standing) liquids in the past, and more. This little red planet perched 3 billion miles away in the Kuiper Belt packed more punch than any other known small world explored, and indeed more punch than many much larger worlds. The variety of terrains, its complex

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so is the subject of intense scientific debate and modeling, and it portends that we can expect more surprises when other small planets in the Kuiper Belt are explored. THE VAST, 1,000-KILOMETER-WIDE SPUTNIK PLANITIA NITROGEN GLACIER Among the varied and active terrains discovered on Pluto, probably the most remarkable

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mission bids by Jupiter Gravity Assist magnetosphere radiation of NASA missions to New Horizons’ study of Jupiter Encounter Science Team, (JEST) New Horizons KBOs. See Kuiper Belt Objects Kennedy Space Center, Cape Canaveral, Florida New Horizons’ launch from as wildlife sanctuary Kerberos (Pluto moon) discovery of shape/rotation of Krimigis, Stamatios “Tom

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” Kubrick, Stanley Kuiper Belt Eris’s discovery in New Horizons’ mission objectives for Kuiper Belt Objects (KBOs) 2014 MU69 New Horizons’ flyby of Kuiper, Gerard Lappa, Linda Levison, Hal Lewis and Clark Lockheed Martin LORRI (

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New Horizons’ launch by New Horizons’ Pluto flyby operations and and New Horizons’ post-Pluto objectives New Horizons’ project development and Pioneer missions by Pluto/Kuiper Belt missions, future, by Pluto mission competitions by Pluto mission study by standardization of spacecrafts by Viking missions by Voyager missions (Mariner Jupiter-Saturn) by National

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media/public engagement plan for mementos sent on mission control for naming of navigation, in-flight objectives, for interstellar space objectives, for Jupiter objectives, for Kuiper Belt objectives, for Pluto planetary science’s birth propelling Pluto 350 Study on Pluto flyby during project crew sizes during publicity/press on Russian collaboration interest

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Phobos launch by Sputnik launch by Space Daily space debris hazards Space Research Institute, Moscow SpaceShipOne spacecraft Space Telescope Science Institute, Baltimore, Maryland Spencer, John Kuiper Belt object search by New Horizons’ “hazards campaign” research by on Pluto flyby findings Spielberg, Steven Sputnik mission (Soviet Union) Sputnik Planitia (Pluto glacier) SSES. See

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running/standing liquid in past as Pluto’s small moons’ rotations/spin axes as Trafton, Larry Triton (Neptune moon) Tvashtar volcano, Io Twitter 2014 MU69 (Kuiper Belt Object) Tyler, Len United States Geological Survey University of Arizona University of Colorado University of Texas Uranus discovery of NASA missions to U.S. Postal

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) ABOUT THE AUTHORS DR. ALAN STERN is principal investigator (PI) of the New Horizons mission, leading NASA’s exploration of the Pluto system and the Kuiper Belt. A planetary scientist, space-program executive, aerospace consultant, and author, he has participated in over two dozen scientific space missions and has been involved at

The Planets

by Dava Sobel · 1 Jan 2005 · 190pp · 52,570 words

in the first zone or the gas and ice giants in the second, they have been given their own new designation of “ice dwarfs,” or “Kuiper Belt objects (KBOs).” The eponymous Gerard Kuiper first conceived of these bodies in 1950. Born and educated in the Netherlands, Kuiper emigrated to the United States

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Kuiper’s myriads began to materialize in the trans-Neptunian deep, astronomers recognized them as his hypothesis come real. The steadily increasing census of the Kuiper Belt counts Quaoar, Varuna, and Ixion, all discovered in 2001 and 2002, among its larger constituents. Their names reflect a modern ethic of ethnic awareness: Quaoar

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is the creation force recognized by the Tonga tribe, the original inhabitants of what is now Los Angeles. Pluto, the premier object in the Kuiper Belt, follows a steeply inclined and highly elliptical orbit. Over a period of 248 years, Pluto alternately soars above the plane of the Solar System and

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from that of any other planet, helped brand Pluto as an oddball from its earliest days. By the standards of the Kuiper Belt, however, the orbit appears common. Some 150 other Kuiper Belt objects trace the same course, and they all avoid collision with Neptune thanks to the resonance agreement among them: Neptune circles

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journey. Now, after the disappointing cancellations of projects such as “Pluto Express” and “Pluto Fast Flyby,” Plutophiles finally have a scout being readied for the Kuiper Belt. NASA’s minimalist “New Horizons,” equipped to map and image Pluto, Charon, and at least one other KBO at close range, should see its promised

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of known KBOs may have increased exponentially, from the several identified to date, to the hundreds of thousands more anticipated. Already the demographics of the Kuiper Belt hint at great waves of migration that characterized early Solar System history. All the KBOs, it seems, were exiled to their present locations, from positions

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also participated in this planetesimal diaspora, they lacked the power to hurl objects entirely beyond the Sun’s reach, and relegated them instead to the Kuiper Belt. As a result of these displacements, Jupiter lost some of its orbital energy and moved in closer to the Sun. Saturn, Uranus, and Neptune, in

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, the ultimate expatriate, to follow an ever more tilted, more elliptical course. Pluto and the other Kuiper Belt residents have thus been worked over by events in the Solar System. Although scientists had hoped the Kuiper Belt might preserve pristine material, unchanged since the formation of the Sun, they now see it as a

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genealogical roots of the solar family must be pursued at a still further remove. Today, ever more distant worldlets are swimming into view beyond the Kuiper Belt. The planetoid Sedna, discovered in 2003 and named for the Inuit goddess of the icy sea, is currently the coldest, most distant known member of

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, as in the Solar System’s home galaxy, the Milky Way. Igneous—a term used to describe rocks formed from once-molten magma or lava. Kuiper Belt—a donut-shaped region beyond the orbit of Neptune, named for Gerard Kuiper, containing hundreds of thousands of icy planetoids. Some of these objects, when

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-looking heavenly object, such as the disk in which a star is born. Oort Cloud—a spherical region of the outer Solar System, beyond the Kuiper Belt, named for Dutch astronomer Jan Oort (1900–1992). Comets from the Oort Cloud follow extremely long-period orbits, and may leave the Solar System after

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one astronomical unit (AU), Jupiter is stationed at 5 AU and Neptune at 30, while Pluto and more than one hundred other members of the Kuiper Belt travel between 30 and 50 AU. The 17-degree tilt of Pluto’s orbit carries it by turns 8 AU above the plane of the

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of Astronomy, Hawaii) and Jane Luu (University of Leiden), while working together at the University of Hawaii’s telescope on Mauna Kea, discovered the first Kuiper Belt Object, which they called “Smiley,” after the spy in the novels of John LeCarré, though its official name remains 1992 QB1. Quaoar, Varuna, and Ixion

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approved KBO names, following IAU guidelines, from among the worldwide catalog of underworld deities. Gerard Kuiper based his prediction of what is now called the Kuiper Belt on the motions of short-period comets such as Comet Halley and Comet Encke. Calculated orbits for these bodies suggested they originated in the

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Kuiper Belt region, and returned to it whenever they disappeared from view. In 1950, the same year Kuiper published this idea, Dutch astronomer Jan Oort used a

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similar argument to predict another, more distant reservoir of comets at 50,000 AU. While the Kuiper Belt is shaped as a torus (donut), the “Oort Cloud” forms a spherical shell. The orbits of short-period comets from the

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Kuiper Belt rarely incline more than twenty degrees from the plane of the ecliptic. Long-period comets from the Oort Cloud, on the other hand, may travel

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Uranus, 197–98 Ice dwarfs, 219 Ingersoll, Andy, 229–30 Io (moon of Jupiter), 157–59 Ishtar (Chaldean goddess), 55 Ishtar Terra (Venus), 64 Ixion (Kuiper Belt object), 220 Juliet (moon of Uranus), 203 Jupiter, 140–62 in astrology, 141–45, 150–51, 155–56 bands of, 146–47 chemical composition of

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, 159 satellites of, 146, 157–59 size of, 145, 204 winds of, 155 Kepler, Johannes, 38–39, 88n, 157n, 165–66 Klaproth, Martin Heinrich, 188n Kuiper Belt objects (KBOs), 219–20, 225–27 Kuiper, Gerard, 207, 219–21, 225–27 Lacus Timorus (Moon), 108 Lada Terra (Venus), 64 Larissa (moon of Neptune

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atmosphere of, 223–24 discovery of, 209, 214–16 formation of, 17 as frozen planet, 20, 224–25 Pluto (cont.) illumination by Sun, 224 in Kuiper Belt, 219–21, 225–27 moon of, 8–9, 217, 221–23 New Horizons, 225 orbit of, 220–21 rotation of, 221 status as planet, 9

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), 41 Proteus (moon of Neptune), 207 Protoplanetary disks, 179 Proto-solar nebula, 15–16 Ptolemy, 33–34, 40, 71–75 Pythagoras, 164–65, 175 Quaoar (Kuiper Belt object), 220 Ring systems and cosmic design, 179 Jupiter, 178 Neptune, 178, 207–8 Saturn. See Saturnian rings Uranus, 178, 181–204, 209 Roche, Edouard

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rings of, 178, 201–4, 209 rotation of, 205–6 size of, 204 Uranus telescope, 185n Utopia (Mars), 133 Valles Marineris (Mars), 127, 134 Varuna (Kuiper Belt object), 220 Venera, 69 Venus, 49–70 acid rain of, 61–62 ancient concept of, 55–56 atmosphere of, 59–60, 61–62, 70 brightness

Catching Stardust: Comets, Asteroids and the Birth of the Solar System

by Natalie Starkey · 8 Mar 2018 · 284pp · 89,477 words

and asteroids Figure 1 The objects in the Solar System. A schematic illustration to show the relative positions of the eight planets, the Asteroid Belt, Kuiper Belt and Oort Cloud, including a scale in Astronomical Units (AU). The size of the Solar System, and the problems in visiting its farthest corners, mean

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distance from the others, but all looking similar in nature. The closer comet neighbourhood is the Kuiper Belt, sometimes known as the Edgeworth-Kuiper Belt, which is still 10 times further from the Sun than the asteroid belt. The Kuiper Belt acts much like the outer suburbs of the city, not quite the very edge, but

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a journey into the city would be a long and arduous one. The Kuiper Belt was first observed in 1992, with its existence having been predicted in 1951 by the Dutch-American astronomer Gerard Kuiper. It was found to be

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made up of hundreds of millions of icy objects which inhabit a region 30 to 55AU from the Sun. The Kuiper Belt includes not only comets but some icy dwarf planets such as Pluto, highlighting the fact that it is made up of a range of different

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-sized objects. The Kuiper Belt comets are on fairly stable and generally elliptical orbits. However, they can be affected by the gravity of the planets, which can disrupt them from

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System where they pass close to the inner rocky planets, or instead end their existence in a fiery solar collision. The comets that exit the Kuiper Belt are known as the short-period comets, with orbital periods of less than 200 years; that is, they take less than 200 years to complete

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same as the planets, and are responsible for the well-known comets such as Halley. At around 50–60AU, there exists a subclass of the Kuiper Belt known as the scattered disc. This is thought to be the source of the Jupiter-family comets, so-called because their current orbits are primarily

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only way that the presence of such objects can be explained is if there is a vast, distant reservoir of comets further out than the Kuiper Belt that surrounds the entire Solar System, acting as a sort of cloud. Hence, the Oort Cloud is assumed to be there. At its closest, the

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2011. The Oort Cloud comets are thought to have formed close to where the orbits of Jupiter, Saturn, Uranus and Neptune are today, whereas the Kuiper Belt comets were initially formed from a disc-like distribution of icy objects beyond the orbit of Neptune and Uranus. You might have noticed from this

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that the relative positions of the Oort Cloud and Kuiper Belt comets are seemingly the ‘wrong’ way around compared with their current locations. Well, in the early Solar System very soon after the planets had formed

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how the Oort Cloud comets ended up being so far from the Sun when they apparently formed closer to it than the comets of the Kuiper Belt. The best way for scientists to account for this observation is if the Solar System experienced a violent reconfiguration that they think is thanks, once

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necessary to go all the way to the asteroid belt, or even worse, out to the far outer reaches of the Solar System to the Kuiper Belt or Oort Cloud, to visit these objects. Rather usefully, the Solar System has a way of diverting asteroids and comets from their normal orbits on

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from repeated transits near the Sun. NEOs are slightly easier to approach with a spacecraft than the same type of objects in the asteroid belt, Kuiper Belt or Oort Cloud. Nevertheless, NEOs can pose a big problem as their altered orbits around the Sun can place them on one that intersects that

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collections allow scientists to analyse a wide range of comets in the Solar System without having to send a spacecraft all the way to the Kuiper Belt or Oort Cloud to collect samples, something that would be very time-consuming and expensive. Nevertheless, if scientists want to specifically analyse the pieces of

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appearances, there is actually plenty of it, it’s not just confined to Earth. In fact, water is abundant from the comets of the cold Kuiper Belt all the way to the constantly shadowed polar craters of Mercury, the closest planet to the Sun. The problem is, these places host water as

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subsequently thrown further out. Despite this, the comets still formed at the largest heliocentric distances of any Solar System objects. You’ll recall that the Kuiper Belt comets are thought to have formed further out than the Oort Cloud comets, even though it is the Oort Cloud comets that are now the

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furthest away. This causes some confusion as to what can be expected for the D/H ratios of these different objects. Early observations of a Kuiper Belt comet, 103P/Hartley 2, by ESA’s Herschel Space Observatory found its D/H ratio to match perfectly with Earth’s water. This was an

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interesting discovery, and one that was used at the time to suggest that Kuiper Belt comets could represent the source of Earth’s water, having collided with Earth during the Late Heavy Bombardment (LHB) and parachuted in their volatile inventory

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. However, the Rosetta mission taught us that comet 67P/C-G, which is a Jupiter-family comet also originating in the Kuiper Belt, has a high D/H ratio, three times that of Earth’s. This is not to say that the measurements of 103P/Hartley 2’s

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. But what about the Oort Cloud comets? Even though they now reside much further out in the Solar System compared with the comets in the Kuiper Belt, they are thought to have originally formed closer to the Sun, near the orbit of Jupiter. As such, Oort Cloud comets might represent a promising

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, Earth can’t tolerate too many of these objects hitting it either for it to still retain a low D/H. If Oort Cloud and Kuiper Belt comets didn’t bring in all of Earth’s water, it seems that another source is required. The next obvious place to look is the

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them slightly easier and cheaper to reach as they transit the inner Solar System after they’ve been diverted from their normal orbits in the Kuiper Belt, Oort Cloud or asteroid belt. Studying space objects in the near-Earth environment still has its challenges, but their relative proximity to Earth has some

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humans remaining firmly in place on Earth. If we want to travel as far as even the closer of the far-flung comet homes, the Kuiper Belt, the edge of which is well over 10 times further than the asteroid belt, then we are in for a long journey and certainly one

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vicinity, acting to give a huge gravity kick. This is exactly what happened when the New Horizons mission to visit Pluto, the king of the Kuiper Belt, zoomed past after its launch from Earth in 2006. Jupiter gave the spacecraft a colossal boost of momentum that increased its speed by 14,000kph

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(9,000mph), dramatically cutting its total journey time to the outskirts of the Solar System and making New Horizons the first spacecraft to document a Kuiper Belt object. When the mission set off, Pluto was still classed as a planet; it was demoted to dwarf planet later in 2006, not that that

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study. New Horizons captured countless stunning images of Pluto’s icy terrains, surfaces that we can probably expect some its Kuiper Belt neighbours to mirror. Like many of the objects in the Kuiper Belt, Pluto was an unknown entity, as telescopic studies have been of limited use due to its vast distance from us

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appeared to have been active in relatively recent geological history. It shows us that there is still a lot to learn about Pluto’s smaller Kuiper Belt neighbours, but this will involve getting a closer glimpse of their surfaces than can be achieved with telescopic study alone. Luckily, New Horizons continues to

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cruise into the Kuiper Belt and it will visit other icy objects at close proximity. Well, at around 3,000km (1,860 miles) away, which is very close in space

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terms. After it’s transited the Kuiper Belt it is due to continue its journey for as long as it has power and is expected to join Voyager 1 and 2, both of

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it out as far as the Oort Cloud, some 2,000 to 5,000AU away. Even Voyager 1, which entered the interstellar space past the Kuiper Belt in 2012, won’t reach the Oort Cloud for another 300 years, and will take 30,000 years to cross it. Unfortunately, even our descendants

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comet was first observed by, and named after, Soviet astronomers Klim Ivanovych Churyumov and Svetlana Ivanovna Gerasimenko in 1969. 67P/C-G originated in the Kuiper Belt, where it had a perihelion distance of around 2.7AU, until February 1959 when a close encounter with Jupiter diverted it inward, where it remains

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the vast majority are thought to be from Jupiter-family comets. Interstellar medium (ISM) – The matter that exists in the space between stars and galaxies. Kuiper Belt – A circumstellar disc of icy objects extending from the orbit of Neptune (around 30AU) to around 55AU. Lagrange point – A part of space where the

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Earth here, here, here, here, here magnetic field here plate tectonics here, here, here silicates here space dust on Earth here ecliptic here, here Edgeworth-Kuiper Belt see Kuiper Belt Enceladus here ER-2 here, here Eris here EROs (easily retrievable objects) here Europa Clipper here European Space Agency (ESA) here, here, here, here

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, here, here, here asteroid belt here Jupiter-family comets here, here, here, here, here, here, here Kant, Immanuel here Kingston Lacy House, Dorset, UK here Kuiper Belt here, here, here, here, here, here, here, here, here Kuiper, Gerard here Lagrange point here, here Laplace, Pierre-Simon here Late-Heavy Bombardment (LHB) here

The Last Stargazers: The Enduring Story of Astronomy's Vanishing Explorers

by Emily Levesque · 3 Aug 2020

to the point where every occultation functions as a one-time opportunity. In 2014, astronomers discovered a little rocky object named 2014 MU69 in the Kuiper Belt, the wide ring of small rocky bodies orbiting our sun in the outer reaches of the solar system. The object itself wasn’t especially remarkable

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was a resounding success, and after zooming past Pluto, New Horizons was still flying. Anticipating this, astronomers had searched for a suitable object in the Kuiper Belt for New Horizons to aim for and came up with 2014 MU69. With a few course corrections, New Horizons would be able to fly past

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. In 1992, Dave Jewitt and Jane Luu were observing at the University of Hawaii eighty-eight-inch telescope and undertaking a dedicated search for Kuiper Belt objects. The Kuiper Belt (named for airborne astronomy pioneer Gerard Kuiper) is a wide ring of small solar system objects, made mainly of rock and ice, that begins

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and stretches to a distance of 4.6 billion miles away from the sun. Today, Pluto and its moon, Charon, are considered members of the Kuiper Belt, but in 1992, with Pluto still designated as a planet, Dave and Jane were leading the search to discover the first object in this hypothesized

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new patch of sky and noticed a very-slow-moving object that, to their cautious excitement, looked exactly like what they’d expect for a Kuiper Belt object. The third and then fourth image confirmed their expectations, with the object moving in a gloriously slow and straight line. At this point, they

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again? In the end, they were able to measure a distance and a size for the object, confirming it as the first discovery of a Kuiper Belt object. Today, it’s known as Albion, a rocky body over seventy miles in diameter orbiting the sun from just over four billion miles away

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, and it’s one of an estimated thirty-five thousand objects like it in the Kuiper Belt. In other cases, astronomers will rely on friends and acquaintances or simply the power of persuasion to capture and follow an exciting new object in

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be done with them is anything but dull. Mike Brown described a robotic survey searching for Kuiper Belt objects—similar to the work Dave Jewitt and Jane Luu had done by hand early on, when the Kuiper Belt was first being studied—that used the recently roboticized forty-eight-inch telescope at Palomar Observatory

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the setup and work of the telescope is standard, the methods for analyzing the data will be fairly standard too. The program used for the Kuiper Belt object search would throw out anything stationary and keep anything that looked like it might be moving, which Mike could then review by hand. It

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on any given morning, there were usually one to two hundred potential moving objects for Mike to check. Every couple of days, a bona fide Kuiper Belt object would crop up, and each one would come with a small frisson of excitement. On one January morning in 2005, Mike was sorting through

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scribbling notes, slowly realizing as he worked that he was looking at a real and absolutely huge distant object in the Kuiper Belt. The discovery turned out to be Eris, the largest Kuiper Belt object ever found at the time. Though its size was ultimately downgraded (it’s smaller than Pluto by about fifty

The Interstellar Age: Inside the Forty-Year Voyager Mission

by Jim Bell · 24 Feb 2015 · 310pp · 89,653 words

others charted in the mid-1960s. It is destined to continue on through a zone of thousands of small, icy planets beyond Neptune called the Kuiper Belt and enter interstellar space sometime in the next few decades. But it was launched without an interstellar message like Voyager’s on board. Perhaps this

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. Maybe active plumes or nitrogen-powered volcanoes would have been discovered. Charley Kohlhase is less sanguine. “I don’t think a far-off little, now–Kuiper Belt Object like Pluto, and the trip time and whether you could make it there or not, would ever have beaten out Titan. Most of the

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, you might say. Today, taking advantage of substantial improvements in telescopes and camera detectors over the past few decades, more than 1,200 of these Kuiper Belt Objects, or KBOs, as they are now known, have been discovered. Many of them, like Pluto, are in an orbital resonance dance with Neptune that

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that close encounter and was captured by Neptune’s gravity. Voyager’s flyby of Triton, then, may have been humanity’s first encounter with a Kuiper Belt Object, a small planetlike body that originally formed in the cold reaches of the outer solar system, and which may provide a glimpse into the

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system does not end at Pluto. Starting in 1992, astronomers have been discovering more and more relatively large, Pluto-sized planetary bodies lurking in the Kuiper Belt beyond Neptune. Almost 1,300 KBOs are now known, and the census is far from complete. The largest one yet found is called Eris, and

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graphical plots of the orbits and positions of all the more than 650,000 presently known asteroids and comets in the solar system, including the Kuiper Belt Objects. The lists are online at minorplanetcenter.net/iau/lists/MPLists.html; to see the KBO list, click on “Transneptunian Objects,” the more generic name

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, 48, 49, 59, 103–132, 107–108, 109, 120–121 Voyager’s radio transmissions from, 63 Jupiter Icy Moons Explorer (JUICE), 126 Kaguya, 237 KBOs (Kuiper belt objects), 147, 217–218 Kepler, 284–288 Kohlhase, Charley, 55, 68–69, 105, 106–107, 110, 135, 136, 138, 140, 147–148, 159, 182, 200

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, 201–202, 219 Kuiper, Gerard P., 217 Kuiper Airborne Observatory, 184 Kuiper Belt, 97, 242 Kuiper belt objects (KBOs), 147, 217–218 Laplace, Pierre-Simon, 115 Lemmon, Mark, 238–239 Le Verrier, Urbain, 43, 192–194, 211 LIFE magazine, 227, 229

The Crowded Universe: The Search for Living Planets

by Alan Boss · 3 Feb 2009 · 221pp · 61,146 words

did not necessarily mean that Jupiters were common. Jupiter protects us from the comets that revolve in the Kuiper Belt beyond Neptune’s orbit. When a malevolent comet decides to break out of the Kuiper Belt and make a suicidal dash toward Earth, Jupiter plays the role of the batsman protecting the wicket in

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with the problem of Pluto’s planethood. It had become clear that Pluto was the largest known member of the swarm of comets in the Kuiper Belt, a region named after the same Gerard Kuiper who had first suggested gravitational instability as a means for forming gas giant planets. Many

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Kuiper Belt objects have orbits similar to that of Pluto, and they had been found by the hundreds, making the situation similar to that of Ceres in

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detected from Earth. The same fate had befallen Pluto. It was merely the first—and so far the largest, until Xena—body detected in the Kuiper Belt. By the same reasoning that had led to the demise of Ceres’s claims to planethood in the early 1800s, it seemed that Pluto deserved

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’s Department of Space Studies in Boulder, Colorado. Marsden’s Center is charged with keeping track of the myriad minor planets, the denizens of the Kuiper Belt, and anything else that is found wandering dazed around the Solar System pushing a shopping cart. Stern was the leader of NASA’s first robotic

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a planet after all. Because Marsden was presented daily with evidence that Pluto was the largest known member of a growing swarm of increasingly large Kuiper Belt comets, he might have been expected to have a somewhat different point of view than Stern on the issue of Pluto’s planethood. It is

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; it was looking like a Chicago Democratic election. I had proposed as a compromise that we create several different categories: the eight major planets, the Kuiper Belt planets (Pluto, Xena/2003 UB313, and others), and the historical planets (the major planets plus Pluto). Given the vote, it was clear that the Working

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be massive enough to have cleared their surroundings of any competing pretenders to planethood. Given that Pluto had lots of similar-sized siblings in the Kuiper Belt, Pluto would not be a planet if Resolution 5A passed, and it did in a landslide. Yellow cards were everywhere, and there was no need

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should be called a “dwarf planet,” and this resolution passed by a vote of 237 to 157. Resolution 6B said that dwarf planets in the Kuiper Belt should be called “plutonian objects.” Plutonian objects? “Plutonian objects” was offered as an improvement on the previous suggestion of “plutons,” which, it turned out, had

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as Strategic Mission Kepler Science Center Kepler’s Third Law of planetary motion Kerr, Richard Kinney, Anne Konacki, Maciej Kornet, Kacper Kortenkamp, Stephen Kuiper, Gerard Kuiper Belt Kulkarni, Shri La Silla Observatory (Chile) Las Campanas Observatory (Chile) Laser comb technique Latham, David Laughlin, Greg Leger, Alain Lehrer, Jim Levy, Eugene Lewinsky, Monica

Pale Blue Dot: A Vision of the Human Future in Space

by Carl Sagan · 8 Sep 1997 · 356pp · 102,224 words

Pluto halfway to the nearest star. The innermost province of the Oort Comet Cloud, of which these new objects may be members, is called the Kuiper Belt, after my mentor Gerard Kuiper, who first suggested that it should exist. Short-period comets—like Halley's—arise in the

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Kuiper Belt, respond to gravitational tugs, sweep into the inner part of the Solar System, grow their tails, and grace our skies. Back in the late nineteenth

Fire and Ice: The Volcanoes of the Solar System

by Natalie Starkey · 29 Sep 2021 · 309pp · 97,320 words

around our Sun, the New Horizons mission arrived at Pluto. It had never been visited by Voyager or any other spacecraft. Pluto sits within the Kuiper Belt, a region of our Solar System beyond the orbits of the planets that hosts millions of small icy objects. Pluto is often referred to as

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the ‘King of the Kuiper Belt’ because of its larger size in comparison to the objects surrounding it, but in reality it should share this title with a number of other

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that’s not where volcanic activity in the Solar System ends. From the moons of Jupiter and Saturn all the way to Pluto in the Kuiper Belt, scientists have found evidence of volcanic activity. Much of it doesn’t necessarily look like what we know so well on Earth, but it does

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Sun on a different plane from all the other planets, also differing from the other small icy objects – most of which are comets – in the Kuiper Belt. The images beamed back to Earth revealed an object that indeed was composed of ice, but that hosted intriguing and somewhat unexpected geological features: dunes

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’t a moon at all. Scientists think that Triton may have originally started out life in the Kuiper Belt, which is home to millions upon millions of icy objects outside the orbit of Neptune. The Kuiper Belt is the origin of many of the short-period comets that enter the inner Solar System and

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is going on under the seemingly inhospitable icy crust. The furthest: Pluto No discussion of ice worlds would be complete without a visit to the Kuiper Belt, home to the dwarf planet Pluto and its lesser-known moons, of which there are five: Styx, Nix, Kerberos, Hydra and Charon. Before the New

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much more interesting, and active, than had been forecast. Pluto and its moons are primitive bodies, much like the other icy objects that share the Kuiper Belt region in which it orbits past our outermost planet. These objects are thought to have formed at the beginning of the Solar System, around 4

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.6 billion years ago, even before the planets, and thus represent the oldest objects to orbit our star. The Kuiper Belt is cold, and everything within it was long thought to be frozen in time since the formation of the Solar System. Sure enough, some

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Kuiper Belt objects sometimes find their way closer to the Sun as comets that get heated up, releasing their ancient inventory of frozen volatiles and dust as

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visit some of these when they pass closer to Earth and learn about the materials they contain. But Pluto, the so-called King of the Kuiper Belt, thanks to its large size, will never be a comet, and so learning about this far-flung world is harder. What New Horizons revealed at

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a world frozen solid, but one that was not frozen in time. It was long known that Pluto was different from many of the other Kuiper Belt objects, being large enough to once be classed as a planet. Of course, now we know that while it is still the largest object in

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the Kuiper Belt, it is not the only large object out there. Other dwarf planets such as Sedna and Eris have since been discovered, meaning this very mysterious

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, here, here, here kinetic energy here, here, here Kola Superdeep Borehole, Russia here Krafft, Katia and Maurice here, here Krakatoa, Indonesia here, here, here, here Kuiper Belt here, here, here, here, here; see also Pluto lahars here, here Laki, Iceland here, here, here land formation/transformation flood basalts here islands here, here

The Case for Space: How the Revolution in Spaceflight Opens Up a Future of Limitless Possibility

by Robert Zubrin · 30 Apr 2019 · 452pp · 126,310 words

those sharp-minded old-time Yankees if they could awake from their graves and look into the future to see Callisto colonists selling…gravity! THE KUIPER BELT AND OORT CLOUD It is generally considered that beyond the Sun's family of planets there is absolute emptiness extending for light-years until you

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space. —Freeman Dyson, 1972 As mentioned earlier, beyond Neptune lie two zones of asteroid-sized objects rich in volatiles. The innermost such region is the Kuiper Belt. Consisting of millions of iceteroids orbiting more or less in the same plane as the planets (“the ecliptic”), it begins about 30 AU and extends

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means that someday, for security purposes if no other, there will be a need for a substantial human presence and technical capability in both the Kuiper Belt and the Oort cloud. But there may be other reasons that drive humans to populate this vast archipelago of cosmic islands. Based on analysis of

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mirror would have to be the size of the continental United States. The only viable alternative based on currently known physics is fusion. In the Kuiper Belt, it might be possible to get helium-3 shipped out from mining operations around Neptune. Oort cloud settlements would be too far out to obtain

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see the establishment of many new branches of human civilization on the moon, Mars, the asteroids, the satellites of the outer planets, and even the Kuiper Belt, organized in accordance with myriads of divergent social and political concepts. Most of the truly novel ones may fail because, for the most part, things

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–50 orbital research labs, 47–48, 50 of outer solar system, 161–62 commercial development of Titan, 162–65 Jovian system, 166–70 in the Kuiper Belt and Oort Cloud, 171–72 space business parks, 50–51 space tourism, 45–47 space triangle trade (Earth-Mars-asteroids), 140–42 See also mining

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–79, 79 energy sources, 82–91 needed to fulfill Noah's Ark Egg project, 211 and settling in the outer solar system, 173–74 in Kuiper Belt and Oort Cloud, 172 solar system energy resources, 159 See also electricity, generating Engines of Creation (Drexler), 233 ENI, 176 entrepreneurship. See commercial benefits of

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departure velocity (hyperbolic velocity) hypersonic, 41, 277, 291, 341 Hyper V, 180 IAC (International Astronautical Congress), 107, 110 iceteroids, 152, 170–72, 221. See also Kuiper Belt; Oort Cloud Ida (asteroid), 130 “Ignitor,” 177 IKAROS solar sail spacecraft, plate 13, 197 Ikin, Kirby, 332 ilmenite (FeTiO3), 91, 145–46 “imploding liner” concept

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Krakowski, Robert, 175 K-T event (asteroid eliminating dinosaurs), 265, 290–91, 298–99 K-type stars, 237, 259, 265, 266, 319 Kuiper, Gerard, 152 Kuiper Belt, 170–72, 321 water in, 170, 171 Kulcinski, Jerry, 83 Laberge, Michel, 179 Lagrange point (Earth and moon gravity in balance), 95 Lambert, James, 180

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), 212 water on asteroids, 130, 131, 140, 142–43, 294, 297 on Jupiter's moons, plate 10, 153–54, 167 Kepler mission finding, 242 in Kuiper Belt, 170, 171 on Mars, 14, 101, 102–103, 105–106, 109, 113–15, 117, 118, 120, 146–49, 218, 222, 297 on the moon, 13