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Beyond Neptune lies a reservoir of... icy debris left to roam the solar system's dim outer limits having never coalesced into planets... Named for astronomer Gerard Kuiper, who in 1951 predicted the existence of this 3-billion-kilometer-wide swath of icy chunks, the Kuiper belt didn't begin to reveal itself to observers until 1992. Since then, researchers have found more than a thousand bodies filling a doughnut-shaped belt, which extends 30 to about 50 astronomical units from the sun. One astronomical unit is the average distance between the Earth and sun... The puffed-up, elongated orbits and present-day sparseness of the belt all...

If you can make sense of it, here's the article: Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits SCOTT J. KENYON AND BENJAMIN C. BROMLEY The Kuiper belt extends from the orbit of Neptune at 30 AU to an abrupt outer edge about 50 AU from the Sun. Beyond the edge is a sparse population of objects with large orbital eccentricities. Neptune shapes the dynamics of most Kuiper belt objects, but the recently discovered planet 2003 VB12 (Sedna) has an eccentric orbit with a perihelion distance of 70 AU, far beyond Neptune's gravitational influence....

NASA's Spitzer Space Telescope has found a dusty ring of material orbiting nearby Vega which was probably the result of a series of protoplanets smashing into each other. Vega is the fifth brightest star in the sky, located only 25 light-years away in the constellation of Lyra. This dust is constantly being blown out by Vega's intense radiation, so it's unlikely that the star has had this much dust for its entire lifetime. Instead, this ring must have been formed recently, perhaps when a Pluto-sized object was pulverized within the last million years or so.

Eighteen rogue planets that seem to have broken all the rules about being born from a central, controlling sun may force a rethink about how planets form, astronomers said on Thursday... "The formation of young, free-floating, planetary-mass objects like these is difficult to explain by our current models of how planets form," Zapatero-Osorio said... They are not linked to one another in an orbit, but do move together as a cluster, she said... Many stars in our own galaxy, the Milky Way, may have formed in a similar manner to the Orion stars, she said. So there could be similar,...

At my age, I really should have expected this to happen. All of a sudden I'm seeing lots of little clues that the 1980s are making something of a nostalgic comeback. High school kids I speak to as part of my job have started wearing thin ties and studded belts, and I thoroughly approve of their newly spiked and teased hairstyles. The other day I saw a pair of plastic sandals (remember Jellies?) in a store window and heard Bon Jovi playing on a "classic rock" station. That's right; I'm a golden oldie. Take, for instance, the fact that when...

The University of Arizona Lunar and Planetary Laboratory is launching its Fall 2009 Evening Lecture Series with talks on wandering solar system planets and searches for hazardous asteroids from Mount Lemmon... Planetary sciences professor Renu Malhotra will speak on "Migrating Planets" on Tuesday, Sept. 15. [whoops] Did the solar system always look the way it is now? New studies by Malhotra and others find that the outer planets -- Jupiter, Saturn, Uranus and Neptune -- were more tightly clustered in the early solar system, then moved away from each other. Malhotra's models show that as the solar system evolved, Jupiter...

Neptune's own existence was a puzzle until recently. The dusty cloud that gave birth to the planets probably thinned out further from the sun. With building material so scarce, it is hard to understand how Uranus and Neptune, the two outermost planets, managed to get so big. But what if they formed closer in? In 2005, a team of scientists proposed that the giant planets shifted positions in an early upheaval (New Scientist, 25 November 2006, p 40). In this scenario, Uranus and Neptune formed much closer to the sun and migrated outwards, possibly swapping places in the process. That...

The gravitational pull of large gas giant planets can affect the orbits of smaller planets; that scenario is thought to have occurred in our own solar system. In some cases, the smaller planet may be flung into a much wider orbit, perhaps even 100 times wider than Pluto's. In the case of single stars, that's normally how it ends. In a binary star system, however, the two stars may play a game of "cosmic pinball" with the poor planet first. Moeckel and Dimitri conducted simulations of binary star systems, with two sun-like stars orbiting each other at distances between 250...

Researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University estimate that "nomad" planets, ejected from their home stellar system and now free-floating through the Milky Way, could outnumber stars by as many as 100,000 to 1. Earlier estimates were more like a handful to 1, though previous studies have only counted unbound planets more massive than Jupiter. To estimate the number of unbound planets as small as Pluto that could be roaming the galaxy, Louis Strigari (KIPAC), lead author of the study, began with a basic rule of nature: where a few big objects are...

At least 5 percent of the comets orbiting our sun may have been stolen from other stars, scientists say. Our solar system is thought to include trillions of comets -- small chunks of rock and ice -- that circle the sun in a spherical swarm called the Oort cloud, a region that extendsabout 100,000 times the distance from the Earth to the sun in any direction. The average distance between the Earth and sun is 93 million miles (150 million kilometers). Now scientists suggest that many of these bodies may actually have originated around other stars and were snatched up...

Life as we know it exists on a cozy planet in a stable orbit around a sun shining brightly in its sky. But a new study hints that the most common life in the universe might exist deep inside eternal-night worlds far from any star, adrift in the icy dark of interstellar space. Researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University estimate that "nomad" planets, ejected from their home stellar system and now free-floating through the Milky Way, could outnumber stars by as many as 100,000 to 1. Earlier estimates were more like a...

Some Stars Capture Rogue Planets by Staff Writers Boston MA (SPX) Apr 20, 2012 New research suggests that billions of stars in our galaxy have captured rogue planets that once roamed interstellar space. The nomad worlds, which were kicked out of the star systems in which they formed, occasionally find a new home with a different sun. This finding could explain the existence of some planets that orbit surprisingly far from their stars, and even the existence of a double-planet system. "Stars trade planets just like baseball teams trade players," said Hagai Perets of the Harvard-Smithsonian Center for Astrophysics. The...

Researchers say life-bearing planets may exist in vast numbers in the space between stars in the Milky WayA few hundred thousand billion free-floating life-bearing Earth-sized planets may exist in the space between stars in the Milky Way. So argues an international team of scientists led by Professor Chandra Wickramasinghe, Director of the Buckingham Centre for Astrobiology at the University of Buckingham, UK. Their findings are published online in the Springer journal Astrophysics and Space Science. The scientists have proposed that these life-bearing planets originated in the early Universe within a few million years of the Big Bang, and that...

Astronomers used ESO's Very Large Telescope and the Canada-France-Hawaii Telescope to find CFBDSIR2149, a free-floating planet with the mass of Jupiter that seems to wander through space without orbiting around a star like most planets we know do. In addition, the planet is actually relatively close to our solar system, only 100 light-years away, and offers scientists a more intimate setting to study a planet and its atmosphere. This isn't the first time that a free-floating object has been found in space, but the previous discoveries haven't provided scientists with enough information to label the body as a planet. Instead,...

Free-floating rogue planets are intriguing objects. These planet-sized bodies adrift in interstellar space were predicted to exist in 1998, and since 2011 several orphan worlds have finally been detected. The leading theory on how these nomadic planets came to exist is that they were they ejected from their parent star system. But new research shows that there are places in interstellar space that might have the right conditions to form planets — with no parent star required. Astronomers from Sweden and Finland have found tiny, round, cold clouds in space that may allow planets to form within, all on their...

"What we're really saying," he explains, "is that there's suggestive evidence there might be something out there." And if a new planet exists — something Matese is emphatically not claiming at this point — then the Wide-field Infrared Survey Explorer (WISE) satellite should already have an image of it stored somewhere in its enormous database. How suggestive the evidence actually is, though, depends on whom you ask. If you ask Ned Wright, a UCLA astrophysicist and WISE principal investigator, he'll tell you, "It's really kind of flimsy. It's there, but they don't have super data." So while the latest version...

U.S. scientists studying "runaway" stars tossed out of our galaxy at great velocities say they've confirmed the same thing can happen to planets. The first runaway star was discovered seven years ago, heading out of the Milky Way at 1.5 million mph, and new research says planets must be doing the same thing -- at speeds up to 30 million mph, the Harvard-Smithsonian Center for Astrophysics reported Thursday. "These warp-speed planets would be some of the fastest objects in our galaxy," astrophysicist Avi Loeb said. "If you lived on one of them, you'd be in for a wild ride from...

Astronomers have discovered a potential "rogue" alien planet wandering alone just 100 light-years from Earth, suggesting that such starless worlds may be extremely common across the galaxy. The free-floating object, called CFBDSIR2149, is likely a gas giant planet four to seven times more massive than Jupiter, scientists say in a new study unveiled Wednesday. The planet cruises unbound through space relatively close to Earth (in astronomical terms), perhaps after being booted from its own solar system. "If this little object is a planet that has been ejected from its native system, it conjures up the striking image of orphaned worlds,...

Odd orbits of remote objects hint at unseen world, new calculations suggest. An as yet undiscovered planet might be orbiting at the dark fringes of the solar system, according to new research.Too far out to be easily spotted by telescopes, the potential unseen planet appears to be making its presence felt by disturbing the orbits of so-called Kuiper belt objects, said Rodney Gomes, an astronomer at the National Observatory of Brazil in Rio de Janeiro. Kuiper belt objects are small icy bodies—including some dwarf planets—that lie beyond the orbit of Neptune. Once considered the ninth planet in our system, the...

Without Jupiter acting as a "cosmic vacuum cleaner" sucking up these dangerous objects, there would be so many catastrophic impacts that life probably wouldn't have evolved on the Earth and we wouldn't be here today... "This vacuum cleaner idea goes back to when the long-period comets coming in from the Oort Cloud were viewed as being the only significant impact risk," says Horner. "In the 1950s there were only one or two near-Earth asteroids known, so they were viewed as oddities." ...Since the 1950s, scientists have discovered more objects in the solar system, and they say many of them could...