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Proposed by British scientists as a joint effort of NASA and the European Space Agency, the mission would offer the first close-up view of Uranus in 25 years.British space scientists are leading plans to send a probe to explore giant ice planet Uranus. They have put forward a detailed proposal to the European Space Agency to launch a joint mission with NASA to the distant world, 1.8 billion miles from the sun. It would give scientists their first close-up views of Uranus since NASA’s Voyager 2 flew past and captured fleeting pictures 25 years ago. The £400million mission is designed...

The Geminid meteor shower, which peaks each year in December... are *not* caused by debris left behind from an active comet... Until recently, the favored view of Phaethon was that it's a dead comet -- the rocky core of a "dirty snowball" that lost its ices after too many close encounters with the sun. ... In June 2009 astronomers using the STEREO sun-watching probe suddenly saw the rocky body flare to life as it neared the sun, brightening by a factor of two... So, not so dead after all. But that brings us back to figuring out what exactly Phaethon...

It's a classic image from every youngster's science textbook: a cutaway image of Earth's interior. The brown crust is paper-thin; the warm mantle orange, the seething liquid of the outer core yellow, and at the center the core, a ball of solid, red-hot iron. Now a new theory aims to rewrite it all by proposing the seemingly impossible: Earth has not one but two inner cores. The idea stems from an ancient, cataclysmic collision that scientists believe occurred when a Mars-sized object hit Earth about 4.45 billion years ago. The young Earth was still so hot that it was mostly...

Deep down, the moon may be more like Earth than scientists ever thought. A new moon-rock study suggests the satellite has an iron core... The moon's core could be a clue to its ancient origins, which have long puzzled astronomers. "Our moon is too big to be a moon," Taylor said. "It's huge compared to the moons we see around other planets, so it has always been suspected that there was something strange in its origin." ...Rock samples from NASA's Apollo 15 and Apollo 17 moon missions of the early 1970s have now shed more light on the moon's origins,...

The new role that quantum information plays in gravity sets the scene for a dramatic unification of ideas in physics One of the hottest new ideas in physics is that gravity is an emergent phenomena; that it somehow arises from the complex interaction of simpler things. A few month's ago, Erik Verlinde at the the University of Amsterdam put forward one such idea which has taken the world of physics by storm. Verlinde suggested that gravity is merely a manifestation of entropy in the Universe. His idea is based on the second law of thermodynamics, that entropy always increases over...

(PhysOrg.com) -- A new theory suggests the Moon was formed after a natural nuclear explosion in the Earth's mantle rather than after the impact of a massive object with the Earth, as previously thought. The problem with the impact hypothesis is that simulations calculate the Moon should be composed of 80% impactor and 20% Earth, whereas in fact the isotope ratios of light and heavy elements found in Moon rocks so far examined are virtually identical to those on Earth. The fission hypothesis is an alternative explanation for the formation of the moon, and it predicts similar isotope ratios in...

The speed of gravity has been measured for the first time. The landmark experiment shows that it travels at the speed of light, meaning that Einstein's general theory of relativity has passed another test with flying colours. Ed Fomalont of the National Radio Astronomy Observatory in Charlottesville, Virginia, and Sergei Kopeikin of the University of Missouri in Columbia made the measurement, with the help of the planet Jupiter. "We became the first two people to know the speed of gravity, one of the fundamental constants of nature," the scientists say, in an article in New Scientist print edition. One important...

Are comets born in great swarms? The puzzling abundance of comets in short solar orbits has led a pair of astronomers to suggest that they are fragments of larger bodies that crumbled as they entered the inner solar system. Short-period comets take less than 200 years to circle the sun and are thought to originate in the Kuiper belt of icy objects beyond Neptune. Some Kuiper-belt objects (KBOs) are in vulnerable orbits that allow the gravity of the outer planets to tug them inwards, where the sun's heat turns them into comets. However, there seem to be too few KBOs...

Enlarge ImageIt's relative. Astronomers have been measuring spin precession in an eclipsing pair of pulsars.Credit: Daniel Cantin/McGill University As if his reputation needed cementing, astronomers have confirmed Albert Einstein's status as a supergenius once more. Studying a unique pair of pulsars--small and extremely dense leftovers from supernova explosions--researchers have measured an effect that was predicted by Einstein's 92-year-old general theory of relativity. The result, they report tomorrow in Science, is almost exactly what the famous physicist had foreseen. In Einstein's relativistic universe, matter curves space and slows down time, and the speed of light remains the only constant. But...

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...

Pluto and its large moon Charon may have been bowled over when they were struck by wayward space rocks in the past, a new study suggests. If so, NASA's New Horizons spacecraft may find evidence of these rolls when it arrives at the distant worlds in 2015. Jay Melosh of the University of Arizona in Tucson, US, first suggested about 30 years ago that the basins gouged out by impacts would redistribute the mass of planetary bodies, causing them to roll over to re-stabilise themselves... Now, Francis Nimmo of the University of California in Santa Cruz, US, who led the...

Mystery of Saturn's Two-Faced Moon Solved Jeanna Bryner Staff Writer SPACE.com Tue Oct 9, 8:45 AM ET Saturn's moon Iapetus has virtually no gray. Rather, its features are all stark black and white. The appearance has long puzzled astronomers. New detailed images suggest sunlight is melting ice on one side of Iapetus, leaving the moon's dark surface exposed, while the opposite half retains its reflective ice-mixed shell. Since the moon's discovery by Giovanni Domenico Cassini in 1671, Iapetus' appearance has baffled astronomers. The leading edge of Iapetus, which faces the direction of its orbit, is black as asphalt, while its...

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...

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...

HORN: What are some examples of genuine predictions made by the exploded planet hypothesis, or EPH? VAN FLANDERN: Here is a list of ten major predictions that have now been validated but for which the results were unknown at the time the predictions were made: that asteroids and comets should be identical types of bodies except for asteroids losing most of their volatiles because of long-term solar heating that these asteroids and comets would have "numerous and commonplace" satellites of their own that the water in meteorites would be salt water rather than pristine water that high-resolution views of irregular...

By Patrick Lannin and Sarah Edmonds STOCKHOLM (Reuters) - Americans John Mather and George Smoot won the 2006 Nobel prize for physics on Tuesday for work on cosmic radiation which helped pinpoint the age of the universe and supported the Big Bang theory of its birth. The Royal Swedish Academy of Sciences, which awarded the 10 million Swedish crown ($1.37 million) prize, said the two men were instrumental to the success of the cosmic background explorer (COBE) satellite program launched by NASA in 1989. Their work took Big Bang theory, which contends the universe began 15 billion years ago as...

The apparent absence of shadows where shadows were expected to be is raising new questions about the faint glow of microwave radiation once hailed as proof that the universe was created by a "Big Bang." In a finding sure to cause controversy, scientists at UAH found a lack of evidence of shadows from "nearby" clusters of galaxies using new, highly accurate measurements of the cosmic microwave background. A team of UAH scientists led by Dr. Richard Lieu, a professor of physics, used data from NASA's Wilkinson Microwave Anisotropy Probe (WMAP) to scan the cosmic microwave background for shadows caused by...

Berkeley Lab Physicist Challenges Speed of Gravity Claim Berkeley - Jun 22, 2003 Albert Einstein may have been right that gravity travels at the same speed as light but, contrary to a claim made earlier this year, the theory has not yet been proven. A scientist at Lawrence Berkeley National Laboratory (Berkeley Lab) says the announcement by two scientists, widely reported this past January, about the speed of gravity was wrong. Stuart Samuel, a participating scientist with the Theory Group of Berkeley Lab's Physics Division, in a paper published in Physical Review Letters, has demonstrated that an "ill-advised" assumption made...

Gravity waves analysis opens 'completely new sense' PRESS RELEASE Washington University in St. Louis St. Louis, MO. -- Sometime within the next two years, researchers will detect the first signals of gravity waves -- those weak blips from the far edges of the universe passing through our bodies every second. Predicted by Einstein's theory of general relativity, gravity waves are expected to reveal, ultimately, previously unattainable mysteries of the universe. Wai-Mo Suen, Ph.D., professor of physics at Washington University in St. Louis is collaborating with researchers nationwide to develop waveform templates to comprehend the signals to be analyzed. In...

A FIFTH terrestrial planet may once have orbited between Mars and Jupiter. Although gravitational disturbances would have sent the planet hurtling into the sun or out into space long ago, traces of this long-gone world may still be visible in part of the asteroid belt today. Recent simulations have suggested that the gas giants of our solar system formed with circular orbits but moved into their more elongated paths about 4 billion years ago – 700 million years after the solar system formed. While the gas giants were in circular orbits, rocky planets should have formed in stable orbits out...