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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...

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...

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...

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...

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...

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...

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...

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,...

Scattered about the Milky Way are floating, Jupiter-mass objects, which are likely to be planets wandering around the Galaxy's core instead of orbiting host stars. But these planets aren't rare occurrences in the interstellar sea: the drifters might be nearly twice as numerous as the most common stars. "This is an amazing result, and if it's right, the implications for planet formation are profound," says astronomer Debra Fischer at Yale University in New Haven, Connecticut. To find the wanderers, scientists turned their telescopes towards the Galactic Bulge surrounding the centre of the Milky Way. Using a technique called gravitational microlensing,...

Astronomers have discovered a whole new class of alien planet: a vast population of Jupiter-mass worlds that float through space without any discernible host star, a new study finds. While some of these exoplanets could potentially be orbiting a star from very far away, the majority of them most likely have no parent star at all, scientists say. And these strange worlds aren't mere statistical anomalies. They likely outnumber "normal" alien planets with obvious parent stars by at least 50 percent, and they're nearly twice as common in our galaxy as main-sequence stars, according to the new study. Astronomers have...

"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...

Astronomers have confirmed the first discovery of an alien planet in our Milky Way that came from another galaxy, they announced today (Nov. 18). The Jupiter-like planet orbits a star that was born in another galaxy and later captured by our own Milky Way sometime between 6 billion and 9 billion years ago, researchers said. A side effect of the galactic cannibalism brought a faraway planet within astronomers' reach for the first time ever. [Illustration of the extragalactic planet] "This is very exciting," said study co-author Rainer Klement of the Max-Planck-Institut fur Astronomie (MPIA) in Heidelberg, Germany. "We have no...