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Presently, our solar system is known to contain 4 fully-fledged rocky worlds: Mercury, Venus, Earth and Mars; 2 ice-giants: Neptune and Uranus; 2 gas-giants, Saturn and Neptune; 5 dwarf-planets, Ceres. Pluto, Eris, MakeMake, Haumea; around 100 moons; and an unknowable number of comets, asteroids and minor planets. Indeed, we’ve only begun to understand the full scope of our local corner of our galaxy, and new information emerges on a monthly-basis, yet there a number of seemingly obvious things that remain unknown. For instance, long before Pluto’s existence was deduced, astronomers scoured the outer solar system in search of another large...

In their studies, the team analyzed the effects of what is called the ‘Kozai mechanism,’ which is related to the gravitational perturbation that a large body exerts on the orbit of another much smaller and further away object. They looked at how the highly eccentric comet 96P/Machholz1 is influenced by Jupiter (it will come near the orbit of Mercury in 2017, but it travels as much as 6 AU at aphelion) and it may “provide the key to explain the puzzling clustering of orbits around argument of perihelion close to 0° recently found for the population of ETNOs,” the team...

Our sun may indeed have a far-flung gravitationally-bound companion — just not with the size or orbit that could have triggered periodicity in earth’s paleontological record, say astrophysicists now actively searching data from NASA’s WISE (Wide-field Infrared Survey Explorer) spacecraft. For decades astronomers and paleontologists have debated whether our sun has a stellar mass M-dwarf companion dubbed “Nemesis” that could have caused a 26 million-year periodicity in earth’s cometary impact record. Such a small M-dwarf star has long been ruled out by WISE data, since observers would surely have spotted an object larger than roughly five Jupiter masses. However, John...

The last extinction event, 11 million years ago, saw 10 per cent of the Earth’s inhabitants wiped out. This means there is around 16million years until the next event takes place, although the graph shows that it occasionally the event takes place up to 10 million years early. Asteroids crashing into the Earth are commonly believed to be one of the main reasons behind mass extinctions like that suffered by the dinosaurs - the Cretaceous-Tertiary (KT) extinction. The extinction wiped out more than half of all species on the planet clearing the way for mammals to become the dominant species...

The 4.6-billion-year history of our solar system is nowhere crystal clear, astronomers admit. Instead, it's filled with questions as to the origin of some of its most remarkable feats. Here is a top 6 of these mysteries, as compiled by New Scientist... Another thing that concerns astronomers is the existence of Planet X, a hypothetical celestial body that supposedly circles our Sun on an orbit somewhere behind Pluto. Experts say that the distance it revolves around the Sun can only imply that the planet is frozen, but say that it could be as big as Mars, or even Earth. However,...

Japanese scientists believe another planet, up to two-thirds the size of Earth, is orbiting in the far reaches of the Solar System... "Because of the very cold temperature, its surface would be covered with ice, icy ammonia and methane," said lead researcher Tadashi Mukai. The study by Mukai and co-worker Patryk Lykawka will be published in the April issue of the Astronomical Journal. "The possibility is high that a yet unknown, planet-class celestial body, measuring 30 per cent to 70 per cent of the Earth's mass, exists in the outer edges of the Solar System," says a statement released by...

A theory is hereby proposed that an unknown mega-massive planet has, for billions of years, been orbiting at 77.2 AU from the sun -- within a 44 AU-wide, virtually empty Great Void that surrounds the Kuiper Belt (One AU = 93 million miles, the mean Earth-Sun distance). The Void is postulated to have been formed by strong gravitational attraction of the unknown planet having removed all CKBOs (Classical Kuiper Belt Objects) that had existed previously in the vicinity of the massive planet's huge orbit... The 77.2 AU distance from the sun of the proposed unknown planet is derived from a...

We assume that if the sun has a companion, it has a period of 27 Myr corresponding to the periodicity seen in cometary impacts on earth. Based on this assumption, it is seen that the inner Lagrangian point of the interaction between the Sun and its companion is in the Oort cloud. From this we calculate the mass – distance relation for the companion. We then compute the expected apparent magnitude (visible and J band) for the companion using the models of Burrows... We then compare this with the catalogue completeness of optical and infrared catalogues to show that the...

IN THE dark reaches of the solar system lurk swarms of hidden worlds. Too small and too distant to reflect sunlight, they have remained under the cover of darkness for billions of years. But now the outer solar system is giving up its secrets. And with them comes an astonishing claim: "It's quite possible that there is a halo of planets surrounding our solar system, just waiting to be found," says Eugene Chiang, an astronomer at the University of California, Berkeley. What makes Chiang's claim so surprising is the sheer number and size of these planets. Weighing more than...

In 1846, researchers noticed that Uranus was wobbling in a way that confounded Newton's Law of Motion. This meant they had two options: rewrite the most time-honoured of the laws of physics, or "invent" a new planet to account for the extra gravitational pull. Compared to Newton's reputation, an eighth planet seemed much less massive and Neptune was discovered. Today scientists working in the University of Louisiana have discovered a statistical anomaly of similar proportions. Professors John Matese, Patrick Whitman and Daniel Whitmire have studied the orbits of comets for 20 years, and their recent findings have led to startling...

Nasa scientists are searching for an invisible 'Death Star' that circles the Sun, which catapults potentially catastrophic comets at the Earth. The star, also known as Nemesis, is five times the size of Jupiter and could be to blame for the impact that wiped out the dinosaurs 65 million years ago. The bombardment of icy missiles is being blamed by some scientists for mass extinctions of life that they say happen every 26 million years Nemesis is predicted to lie at a distance equal to 25,000 times that of the Earth from the Sun, or a third of a light-year....

Our sun may have a companion that disturbs comets from the edge of the solar system — a giant planet with up to four times the mass of Jupiter, researchers suggest. A NASA space telescope launched last year may soon detect such a stealth companion to our sun, if it actually exists, in the distant icy realm of the comet-birthing Oort cloud, which surrounds our solar system with billions of icy objects. The potential jumbo Jupiter would likely be a world so frigid it is difficult to spot, researchers said. It could be found up to 30,000 astronomical units from...

"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...

A duo of planetary astronomers has grabbed media attention by claiming a planet four times the size of Jupiter may be lurking in the outer solar system. They call the planet Tyche. Many astronomers, however, say it probably isn't there. The claim by John Matese and Daniel Whitmire of the University of Lousiana-Lafayette is not new: They have been making a case for Tyche since 1999, suggesting that the giant planet's presence in a far-flung region of solar system called the Oort cloud would explain the unusual orbital paths of some comets that originate there.

Scientists believe they may have found a new planet in the far reaches of the solar system, up to four times the mass of Jupiter. Its orbit would be thousands of times further from the Sun than the Earth's - which could explain why it has so far remained undiscovered. Data which could prove the existence of Tyche, a gas giant in the outer Oort Cloud, is set to be released later this year - although some believe proof has already been garnered by Nasa with its pace telescope, Wise, and is waiting to be pored over. A new world?...

A wall painting (fresco) of Tyche, the Greek goddess of fortune, was exposed during the 11th season of excavation at the Sussita site, on the east shore of the Sea of Galilee, which was conducted by researchers of the University of Haifa. Another female figure was found during this season, of a maenad, one of the companions of the wine god Dionysus. "It is interesting to see that although the private residence in which two goddesses were found was in existence during the Byzantine period, when Christianity negated and eradicated idolatrous cults, one can still find clear evidence of earlier...