Mars Rover Finds Evidence of Subsurface Water

The ground where NASA's Mars Exploration Rover Spirit became stuck last year holds evidence that water, perhaps as snow melt, trickled into the subsurface fairly recently and on a continuing basis. Stratified soil layers with different compositions close to the surface led the rover science team to propose that thin films of water may have entered the ground from frost or snow. The seepage could have happened during cyclical climate changes in periods when Mars tilted farther on its axis. The water may have moved down into the sand, carrying soluble minerals deeper than less soluble ones.

"The lack of exposures at the surface indicates the preferential dissolution of ferric sulfates must be a relatively recent and ongoing process since wind has been systematically stripping soil and altering landscapes in the region Spirit has been examining," said Ray Arvidson of Washington University in St. Louis, deputy principal investigator for the twin rovers Spirit and Opportunity.

Neutron Star Packs Two Suns' Mass in Size of City

Astronomers have discovered what they say is the mightiest neutron star yet. The super-dense object, which lies some 3,000 light-years from Earth, is about twice as massive as our Sun. That is 20% greater than the previous record holder, the US-Dutch team behind the observation tells the journal Nature. "It's approximately the size of a city, which for an astronomical object is interesting because people can conceive of it pretty easily," the study's lead author told BBC News.

The finding is important, says Dr Demorest's team, because it puts constraints on the type of exotic material that can form a neutron star. Such objects are thought to be the remnant cores of once giant stars that blew themselves apart at the ends of their lives. As well being fantastically compact, the cores also spin incredibly fast. This particular object, classified as PSR J1614-2230, revolves 317 times a second. It is what is termed a pulsar - so-called because it sends out lighthouse-like beams of radio waves that are seen as radio "pulses" every time they sweep over the Earth.

Discovery Crew Prepares for the Last Lift-off

Thousands of people are expected to turn out on Nov. 1 to watch the final launch of the space shuttle Discovery. Discovery's 35th journey to the International Space Station will be conducted by Commander Steve Lindsey and his five-member crew: Pilot Eric Boe and mission specialists Michael Barratt, Tim Kopra, Alvin Drew and Nicole Stott. The 11-day mission will deliver a pressurized logistics module called Leonardo, a humanoid robot named Robonaut 2 and key spare parts to the space station. Two space walks are also planned, AFP reported.

Lift-off is scheduled for 4:40 p.m. EDT. Tickets for viewing the launch on the NASA Causeway, about 6 miles from the shuttle's Launch Pad 39A at Kennedy Space Center in Cape Canaveral, Fla., sold out weeks ago, Space.com reported. But fans of the space program are also expected to gather in Space View Park and Parrish Park in Titusville, Fla., and at Port Canaveral.

"Starquakes" Yield New Insights About Stars

An international cadre of scientists that used data from NASA's Kepler spacecraft announced Tuesday the detection of stellar oscillations, or "starquakes," that yield new insights about the size, age and evolution of stars. The results were presented at a news conference at Aarhus University in Denmark by scientists representing the Kepler Asteroseismic Science Consortium (KASC). The team studied thousands of stars observed by Kepler.

Analysis of stellar oscillations is similar to how seismologists study earthquakes to probe the Earth's interior. This branch of science, called astroseismology, produces measurements of stars the Kepler science team is anxious to have. "Using the unparalleled data provided by Kepler, KASC scientists are quite literally revolutionizing our understanding of stars and their structures," said Douglas Hudgins, Kepler Program Scientist at NASA Headquarters in Washington.

ISS Dodges Piece of Old NASA Satellite

The International Space Station has steered clear of space junk. Flight controllers fired thrusters on the space station Tuesday morning. That moved the orbiting lab and its crew of six safely away from a chunk of an old NASA research satellite.

The debris originally was projected to come within one-tenth of a mile of the space station. The latest estimate put the close approach at a half-mile. Because of the uncertainty, NASA elected to move the space station. NASA says the space station relocation will have no significant impact on next Monday's launch of the space shuttle Discovery.

Astronomers Find Oldest Galaxy So Far

Hidden in a Hubble Space Telescope photo released earlier this year is a small smudge of light that European astronomers now calculate is a galaxy from 13.1 billion years ago. That's a time when the universe was very young, just shy of 600 million years old. That would make it the earliest and most distant galaxy seen so far. By now the galaxy is so ancient it probably doesn't exist in its earlier form and has already merged into bigger neighbors, said Matthew Lehnert of the Paris Observatory, lead author of the study published online Wednesday in the journal Nature.

The new galaxy doesn't have a name — just a series of letters and numbers. So Lehnert said he and colleagues have called it "the high red-shift blob. "Because it takes so long for the light to travel such a vast time and distance, astronomers are seeing what the galaxy looked like 13.1 billion years ago at a time when it was quite young — maybe even as young as 100 million years old — Lehnert said. It has very little of the carbon or metal that we see in more mature stars and is full of young, blue massive stars, he said.

Halley's Meteors Streak Past

Watch the skies this week and you could see a piece of Halley's comet, even though it won't be passing Earth until 2061. As the comet travels on its 76-year trip around the sun, it leaves small pieces of itself behind. These meteoroids of dust and ice, travelling at over 237,000 kilometres per hour, collide with the Earth's atmosphere as it crosses the comet's orbit in early May and mid-October.

October's meteors appear to come from the direction of the constellation of Orion and earn it the name of the Orionid meteor shower. Last year, NASA recorded 43 Orionid meteors, most of which burned up more than 96 kilometres above the ground. The shower peaks tomorrow and is best viewed in a clear, dark sky after 11 pm in your local time, when the sky will be at its darkest.

Solar Eclipse Witnessed from Space

NASA's Solar Dynamics Observatory recorded its first lunar transit when the moon passed directly between the spacecraft and the sun. In this newly released image, the dark edge of the moon forms a partial eclipse of the sun. This sharp edge can be used to help calculate the effects of light diffraction on the telescope's optics, allowing operators to correct for this effect.

Onboard the SDO is the Helioseismic and Magnetic Imager instrument. This measures magnetic fields, as well as visible ripples on the surface of the sun caused by the sun's convection zone. This data helps researchers understand our star's influence on Earth and near-Earth space.

Saturn's "Walnut" Moon Mystery Cracked

Saturn's moon Iapetus looks like a walnut because it lies in a "Goldilocks zone" around the giant planet, new research suggests. The moon was once a fast-spinning blob of rock and ice, but its location was just right for locking an unusual feature in place as the spin slowed. In general, moons that form around planets spin due to the motion of debris as it consolidates into a larger orbiting body.

Unlike Saturn's other spherical or ellipsoid moons, Iapetus has a unique, slightly squashed shape with an 8-mile-high mountain range running around much of its middle, like the cusp where the halves of a walnut shell join. Previous theories had suggested this odd ridge formed via plate tectonics or volcanoes. Those models tended to produce a broader "ridge zone" rather than a single narrow feature. In their new model, Kreslavsky and UCSC colleague Francis Nimmo suggest Iapetus formed in a region where the moon was far enough from the planet to retain a lot of its initial spin even after it was fully grown. However, the moon was close enough that Saturn's gravitational forces eventually slowed things down.

First Life-Friendly Exoplanet May Not Exist

Last month, a team of astronomers announced the discovery of the first alien world that could host life on its surface. Now a second team can find no evidence of the planet, casting doubt on its existence. The planet, dubbed Gliese 581 g, was found to orbit a dim, red dwarf star every 37 days, according to an analysis by Steven Vogt of the University of California, Santa Cruz, Paul Butler of the Carnegie Institution of Washington in DC, and their colleagues.

Unlike the four previously known planets in the same system and hundreds of others found throughout the Milky Way galaxy, Gliese 581 g sits in the middle of its host star's habitable zone, where temperatures are in the right range for liquid water to exist. It is also puny enough – weighing about three Earths – to have what is likely a rocky, solid surface. But it might be too early to claim a definitive detection. A second team of astronomers have looked for signals of Gliese 581 g in their own data and failed to find it.

Asteroid Collision Makes Quite a Picture

The dusty wreckage thrown out in the explosive collision of two asteroids has been pictured by spacecraft. The debris stretches for hundreds of thousands of kilometres. US and European scientists tell the journal Nature that a remnant rock about 120m in size sits at the head of this shattered stream of material.

Their investigations using the powerful imaging equipment on the Hubble telescope and the Rosetta probe suggest the pile-up occurred in early 2009. Colin Snodgrass from the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, said the event offered a unique observing opportunity for researchers studying the Solar System. "If you look at the literature on 'recent' asteroid collisions, they tend to talk about things occurring in the past million years or so - that's recent on geological timescales. But on the timescales involved in this event, we're really catching it in the moment of happening."

WISE Starts New Mission... Without Coolant

A prolific NASA space telescope that is mapping the entire sky has run out of vital coolant needed to keep its detectors from warming up, but that hasn't stopped its mission to seek out hidden asteroids, comets and other objects. NASA's Wide-field Infrared Survey Explorer, or WISE, is turning its camera eye on asteroids and comets within our solar system as part of its new NEOWISE Post-Cryogenic Mission.

This allows the space telescope to continue scanning the cosmos despite the lack of frozen hydrogen onboard to keep its infrared detectors as cold as designed. "Two of our four infrared detectors still work even at warmer temperatures, so we can use those bands to continue our hunt for asteroids and comets," said Amy Mainzer of NASA's Jet Propulsion Laboratory in Pasadena, Calif., in a statement. Mainzer is leading the WISE telescope's new mission.

Io in True Color

The strangest moon in the Solar System is bright yellow. This picture, an attempt to show how Io would appear in the "true colors" perceptible to the average human eye, was taken in 1999 July by the Galileo spacecraft that orbited Jupiter from 1995 to 2003. Io's colors derive from sulfur and molten silicate rock. The unusual surface of Io is kept very young by its system of active volcanoes.

The intense tidal gravity of Jupiter stretches Io and damps wobbles caused by Jupiter's other Galilean moons. The resulting friction greatly heats Io's interior, causing molten rock to explode through the surface. Io's volcanoes are so active that they are effectively turning the whole moon inside out. Some of Io's volcanic lava is so hot it glows in the dark.

China Launches Moon Mission

A Chinese rocket carrying a probe destined for the Moon has blasted into space. A Long March 3C rocket with the Chang'e-2 probe took off from Xichang launch centre at about 1100 GMT. The rocket will shoot the craft into the trans-lunar orbit, after which the satellite is expected to reach the Moon in about five days.

Chang'e-2 will be used to test key technologies and collect data for future landings. The latest launch, to test key technologies and gather data, is China's second lunar mission China says it will send a rover on its next mission, and it also has ambitions to put humans on the surface of the lunar body at some future date. The Xinhua News Agency said Chang'e-2 would circle just 15 km above the rocky terrain in order to take photographs of possible landing locations.