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Ceres is the largest object in the asteroid belt, and NASA's Dawn spacecraft will arrive there on March 6. Pluto is the largest object in the Kuiper belt, and NASA's New Horizons spacecraft will arrive there on July 15... The efforts of a very small clique of Pluto-haters within the International Astronomical Union (IAU) plutoed Pluto in 2006. Of the approximately 10,000 internationally registered members of the IAU in 2006, only 237 voted in favor of the resolution redefining Pluto as a "dwarf planet" while 157 voted against; the other 9,500 members were not present... Unlike the larger planets, however,...

A planet is a planet wherever it resides, right? Dave Eicher examines the case of the icy world.In 1930 a young astronomer from Kansas, employed as an observer at Lowell Observatory in Arizona, discovered Pluto. It was the first planet in the solar system to have been discovered since 1846, when astronomers in Germany detected Neptune. Clyde Tombaugh, just 24 at the time, was hailed as a hero, Disney named a cartoon dog after the new planet, and for 76 years the solar system was a happy place. And then, in 2006, the International Astronomical Union (IAU) reconsidered Pluto’s status....

Data from a spacecraft orbiting Earth has revealed ripple structures in the termination shock and heliopause: shifting regions of space that mark one of the boundaries between the space inside the Solar System, and...interstellar space. ...Sun affects the space around it...solar wind, a constant supersonic flow of ionized plasma. It blows out past the planets and the Kuiper Belt, eventually petering out in the great emptiness between the stars. The point at which this flow falls below the speed at which sound waves can travel through the diffuse interstallar medium is called the termination shock, and the point at which...

Unravel the cosmic enigma with our latest video on the elusive "Planet Nine"! Join the quest as astronomers explore gravitational hints, peculiar orbits, and groundbreaking techniques in the relentless search.Are We about to Discover a New Planet in Our Solar System? | 21:46Astrographics | 44.6K subscribers | 329,973 views | February 7, 2024

One of Jupiter's tenuous rings can be seen in this infrared image. (NASA/ESA/CSA/STScI/Judy Schmidt) Given its similarities to its neighbor, Saturn, it seems natural to ask why Jupiter doesn't also have a magnificent, extensive system of visible rings. Alas, it's not the reality. While Jupiter does have rings, they're thin, tenuous, flimsy things of dust, visible only when back-lit by the Sun. According to new research, these discount rings lack bling because Jupiter's posse of chonky Galilean moons keep discs of rock and dust from accumulating the way they do around Saturn. "It's long bothered me why Jupiter doesn't have...

Rather, the comet's behavior is probably typical for comets making their first trip toward the sun — we just haven't been able to observe it before. "What makes this comet special is that it was discovered early," Jewitt said. "We've been able to follow the way the comet changes with distance from the sun over a much larger range than has ever been done before." Comet K2 comes from even farther away than the Kuiper Belt, Jewitt said. The comet's original home was most likely the Oort Cloud, the repository of comets and planetary fragments that extends from 2,000 to...

A new paper describes how the researchers connected the moving dots to find the new TNOs, and also says this new approach could help look for the hypothetical Planet Nine and other undiscovered worlds. The Dark Energy Survey (DES) is designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision. It studies galaxies and supernovas and precisely tracks their movements. This survey has been active since 2013, using the 4-meter Blanco Telescope located at Cerro Tololo Inter-American Observatory (CTIO) in Chile. The...

It's a large moon, the seventh largest in our solar system, and scientists think it was born in the Kuiper Belt before falling into its current location in orbit around the most distant planet. ...Procktor and her colleagues believe they can photograph the moon's entire surface in a single pass. ...On its way past Triton, the spacecraft's flight would be timed in order to see in sunlight the 60 percent or so of its surface that Voyager 2 couldn't see. After the initial approach, the spacecraft would turn its camera back to recapture the 40 percent of the surface Voyager...

At the furthest reaches of the solar system, 2019 will start off with exploration. NASA has given the final green light to its New Horizons spacecraft for a January 1st flyby of Ultima Thule, an object in the Kuiper Belt around a billion miles beyond Pluto. It will be the most distant planetary flyby in human history. Before giving the okay, NASA wanted to make sure that it wasn't passing up any other opportunities for either study or disaster in the area—rings, small moons, and anything else that a probe like New Horizons might want to observe. Pushing through the...

Act Two of the 12-year-old New Horizons mission to Pluto and the solar system’s icy Kuiper Belt is heating up, with less than a month to go before NASA’s piano-sized spacecraft makes history’s farthest-out close encounter with a celestial object. The New Year’s flyby of a mysterious Kuiper Belt object (or objects) known as Ultima Thule (UL-ti-ma THOO-lee) follows up on the mission’s first act, which hit a climax three years ago with a history-making flyby of Pluto. Launched in 2006, New Horizons was never meant to be a one-shot deal. Even before the Pluto flyby, mission managers used the...

Kathryn Volk and Renu Malhotra at the University of Arizona have noticed some strange movement out in the Kuiper belt…movement that they believe could suggest the existence of a tenth planet. ... Objects in the Kuiper belt are far enough away from the other major bodies in our solar system that the gravitational influence of the large planets doesn’t impact them (at least, not to a measurable degree); however, their movements can still be predicted, thanks to sky surveys and a host of advanced technologies. The search for Planet Nine has lead scientists to believe that it is orbiting around...

University of Arizona scientists have uncovered a curious case of missing asteroids. The main asteroid belt is a zone containing millions of rocky objects between the orbits of Mars and Jupiter. The scientists find that there ought to be more asteroids there than researchers observe. The missing asteroids may be evidence of an event that took place about 4 billion years ago, when the solar system's giant planets migrated to their present locations. UA planetary sciences graduate student David A. Minton and UA planetary sciences professor Renu Malhotra say missing asteroids is an important piece of evidence to support an...

Many of the primitive bodies wandering the asteroid belt between Mars and Jupiter are former comets, tossed out of orbit by a brutal ballet between the giant outer planets, said a team of astrophysicists. A commonly accepted theory is that the asteroid belt is the rubble left over from a "proto-planetary disk," the dense ring of gas that surrounds a new-born star. But the orbiting rocks have long been a source of deep curiosity. They are remarkably varied, ranging from mixtures of ice and rock to igneous rocks, which implies they have jumbled origins. The answer to the mystery, according...

Jupiter, the biggest planet in the solar system, might have gained its dominant position after swallowing up a smaller planet, scientists believe. Studies on Jupiter have revealed that the giant planet, which is more than 120 times bigger than the Earth, has an extremely small core that weighs just two to 10 Earth masses. Now scientists have claimed that Jupiter's core might have been vaporised in huge collision with a planet up to ten times the size of Earth, the New Scientist reported. Researchers led by by Shu Lin Li of Peking University in China have modelled what might have...

Boulder, Colo. — Nov. 10, 2011 — Just as an expert chess player sacrifices a piece to protect the queen, the solar system may have given up a giant planet and spared the Earth, according to an article recently published in The Astrophysical Journal Letters. "We have all sorts of clues about the early evolution of the solar system," says author Dr. David Nesvorny of the Southwest Research Institute. "They come from the analysis of the trans-Neptunian population of small bodies known as the Kuiper Belt, and from the lunar cratering record." These clues suggest that the orbits of giant...

The path of true love never runs smooth, it is said. Especially on Valentine's Day. And for young planets, that path turns out to be an inward-moving annulus. A simulation by scientists in France and USA appears to show that Jupiter once strayed to flirt with the inner Solar System, before being "jilted" and sent back to its present-day position. The effect of this was to form the inner planets, according to the theory, which comes up with mass ratios for Earth and Mars similar to that observed today and which, remarkably, also accurately depicts the Asteroid Belt. If the...

Line up Mercury, Venus, Earth and Mars according to their distance from the sun and you'll see their size distribution is close to symmetrical, with the two largest planets between the two smallest. That would be no coincidence -- if the pattern emerged from a debris ring around the sun. Brad Hansen of the University of California, Los Angeles, built a numerical simulation to explore how a ring of rocky material in the early solar system could have evolved into the planets. He found that two larger planets typically form near the inner and outer edges of the ring, corresponding...

Using the new Combined Array for Research in Millimeter Astronomy (CARMA), Eisner and his colleagues observed more than 250 stars in Orion's central region and found that less than 8% had dust disks thought massive enough to create a Jupiter. The radiation from hot, massive stars in the cluster probably clears out a lot of surrounding material and keeps high-mass disks from forming, explains co-author John Carpenter (Caltech). In all, about 10% of the observed stars emit radiation associated with warm dust disks. The results agree almost perfectly with findings by Geoff Marcy (UC Berkeley) and his colleagues, who conclude...

...planets are the most diverse and intricate class of object in the universe. No other celestial bodies support such a complex interplay of astronomical, geologic, and chemical and biological processes... The worlds of our solar system... hardly prepared us for the discoveries of the past decade, during which astronomers have found more than 200 planets. The sheer diversity of these bodies' masses, sizes, compositions and orbits challenges those of us trying to fathom their origins. When I was in graduate school in the 1970s, we tended to think of planet formation as a well-ordered, deterministic process -- an assembly line...

Jupiter increases risk of comet strike on Earth 11:53 24 August 2007 NewScientist.com news service David Shiga Earth experienced an especially heavy bombardment of asteroids and comets early in the solar system's history (Illustration: Julian Baum) Contrary to prevailing wisdom, Jupiter does not protect Earth from comet strikes. In fact, Earth would suffer fewer impacts without the influence of Jupiter's gravity, a new study says. It could have implications for determining which solar systems are most hospitable to life. A 1994 study showed that replacing Jupiter with a much smaller planet like Uranus or Neptune would lead to 1000 times...