Thursday, December 30, 2010

Forecasters Keep Eye on Looming Solar Max

The coming year will be an important one for space weather as the Sun pulls out of a trough of low activity and heads into a long-awaited and possibly destructive period of turbulence. Many people may be surprised to learn that the Sun, rather than burn with faultless consistency, goes through moments of calm and tempest.

But two centuries of observing sunspots -- dark, relatively cool marks on the solar face linked to mighty magnetic forces -- have revealed that our star follows a roughly 11-year cycle of behaviour. The latest cycle began in 1996 and for reasons which are unclear has taken longer than expected to end. "The latest prediction looks at around midway 2013 as being the maximum phase of the solar cycle," said Joe Kunches of the Space Weather Prediction Center at the US National Oceanic and Atmospheric Administration (NOAA).

Monday, December 20, 2010

Total Lunar Eclipse Monday Night

For a few hours on the night of Dec. 20 to Dec. 21, the attention of tens of millions of people will be drawn skyward, where the mottled, coppery globe of our moon will hang completely immersed in the long, tapering cone of shadow cast out into space by our Earth. If the weather is clear, favorably placed skywatchers will have a view of one of nature's most beautiful spectacles: a total eclipse of the moon.

Unlike a total eclipse of the sun, which is only visible to those in the path of totality, eclipses of the moon can usually be observed from one's own backyard. The passage of the moon through the Earth's shadow is equally visible from all places within the hemisphere where the moon is above the horizon.

Wednesday, December 15, 2010

Possible Ice Volcano Spied on Saturn Moon

Scientists said they have found the best evidence yet of ice volcanoes on Saturn's giant moon Titan. Unlike volcanoes on Earth, such a volcano on Titan may spew ice and hydrocarbons instead of molten lava. "We finally have some proof that Titan is an active world," said geophysicist Randolph Kirk of the U.S. Geological Survey, who presented the findings.

The latest evidence comes from the international Cassini spacecraft, which spied two peaks over 3,000 feet tall and what looked like old volcanic flows. Researchers said the landforms resembled Mount Etna in Italy or Laki volcano in Iceland. There's no sign of volcanic activity on Titan, though scientists are keeping watch.

Venus Miss Is Setback for Japanese Program

Researchers and engineers working with Japan's Akatsuki spacecraft were spared the worst-case scenario on 6 December. Although Akatsuki failed to make contact for more than an hour after the scheduled engine burn that was to place it in orbit around Venus, it did eventually call home. But the news was not promising. Not only had Akatsuki been tumbling out of control for a period of time, it had failed to enter orbit. It will now have to circle the Sun for six years before it gets a second chance.

The failure derails an ambitious program of research into Venus's atmosphere, and marks the third time that the Japan Aerospace Exploration Agency (JAXA) has battled mechanical problems on a mission to another Solar System body. In 1998, a faulty valve caused a loss of fuel on JAXA's Nozomi spacecraft, which ultimately prevented it from orbiting Mars. And the Hayabusa probe, which returned a minute quantity of asteroidal material to Earth this year, experienced a variety of near-fatal problems.

Tuesday, December 14, 2010

Voyager Near Solar System's Edge

Voyager 1, the most distant spacecraft from Earth, has reached a new milestone in its quest to leave the Solar System. Now 10.8 billion miles) from home, the veteran probe has detected a distinct change in the flow of particles that surround it. These particles, which emanate from the Sun, are no longer travelling outwards but are moving sideways.

It means Voyager must be very close to making the jump to interstellar space - the space between the stars. The newly reported observation comes from Voyager 1's Low-Energy Charged Particle Instrument, which has been monitoring the velocity of the solar wind. This stream of charged particles forms a bubble around our Solar System known as the heliosphere. The wind travels at "supersonic" speed until it crosses a shockwave called the termination shock. At this point, the wind then slows dramatically and heats up in a region termed the heliosheath. Voyager has determined the velocity of the wind at its location has now slowed to zero.

Monday, December 13, 2010

Saturn's Rings: Leftovers from a Cosmic Murder?

One of the solar system's most evocative mysteries—the origin of Saturn's rings—may be a case of cosmic murder, new research suggests. The victim: an unnamed moon of Saturn that disappeared about 4.5 billion years ago. The suspect: a disk of hydrogen gas that once surrounded Saturn when its dozens of moons were forming, but has now fled the crime scene. The cause of death: A forced plunge into Saturn. And those spectacular and colorful rings are the only evidence left.

As the doomed moon made its death spiral, Saturn robbed its outer layer of ice, which then formed rings, according to a new theory published online Sunday in the journal Nature. A large disk of hydrogen gas circled Saturn and that helped both create and destroy moons. Large inner moons probably made regular plunges into the planet, pulled by the disk of gas. These death spirals took about 10,000 years and the key to understanding the rings' origins is what happened to them during that time. According to Canup's computer model, Saturn stripped the ice away from a huge moon while it was far enough from the planet that the ice would be trapped in a ring.

Geminid Meteor Shower Expects Dazzling Display

Stargazers who stay up late tonight will see what NASA describes as the best meteor shower of the year. The Geminid meteor shower is comprised of debris from 3200 Phaethon, an extinct comet that was once thought to be an asteroid, The Associated Press reported. When the earth passes through this debris stream, the meteors, or shooting stars, seem to fall from the Gemini constellation.

"Of all the debris streams Earth passes through every year, the Geminids' is by far the most massive," astronomer Bill Cooke said. "When we add up the amount of dust in the Geminid stream, it outweighs other streams by factors of 5 to 500." According to PC Magazine, the 2010 Geminids promises to fill the night sky with 50 to 120 shooting star sightings per hour. Although the shower will be visible from almost any point on Earth until Dec. 16, the best views will be seen in the Northern Hemisphere between midnight and sunrise early Tuesday.

Tuesday, December 7, 2010

Dancing Stars Turn on the Red Light

For the first time, astronomers have watched the spiralling dance performed by two stars merging into a single star. The observations, taken between 2001 and 2008, suggest a solution to the vexed problem of how rare "red novae" form. Most novae are blue and occur when material on a white dwarf star explodes. But what causes red novae has been a mystery.

In September 2008, the red nova V1309 Scorpii appeared in the Milky Way. Fortunately, it was positioned in a part of the sky being watched by the Optical Gravitational Lensing Experiment (OGLE), a Polish-run programme using data from a telescope at the Las Campanas Observatory in Chile to search for signs of dark matter and planets. As a result, the team had inadvertently captured the process that sparked the red nova.

Saturn's Strange Propellers Are Clues to Formation

For six years, the Cassini spacecraft has been touring Saturn and its magnificent rings. Unlike previous spacecraft, which have snatched a passing glimpse of the planet on their way to the edges of the solar system, Cassini has beamed back stunningly detailed images year after year. Among the most striking are structures shaped like aircraft propellers. They are the wakes created by unseen moons as they plough through the icy rubble orbiting around Saturn. Dozens of propellers have been spotted in the A-ring, a band 14,000 kilometres wide and only 10 metres deep.

The moons themselves are too small even for Cassini to see directly because they are only a few kilometres to a few hundred metres across. In contrast, their propeller-shaped wakes can be thousands of kilometres long, and some have now been observed orbiting Saturn for several years. They form as a result of a moon's gravity tugging on the surrounding material. The debris inside its orbit, being closer to Saturn, is moving faster, and the perturbation therefore quickly overtakes the moon, creating a long, thin wake ahead of it. This is the leading blade of the propeller. Meanwhile, the material outside the moon's orbit is moving more slowly, creating the trailing blade.

Japan Probe Reaches Venus but Shuts Down

A Japanese space probe sent to the thick clouds of Venus shut itself down, and its future looks as hazy as the planet it was built to study. The probe, called Akatsuki, which means "dawn," reached Venus on Tuesday to orbit Earth's neighbor on a two-year mission. But communication problems left scientists in the dark about whether it was successfully in orbit.

An American scientist on the probe's research team said the probe shut itself partially down and is in safe mode. That means it is sending back signals indicating it is alive, but not transmitting any data. At first, controllers back on Earth lost contact with the probe and got modulating signals indicating that spaceship may be wobbling a bit. But after a few hours, engineers at NASA and the Japanese space agency, JAXA, were able to lock on the probe's signal and found it shut itself down to protect itself, Limaye said.

Monday, December 6, 2010

Stripes Are Back in Season on Jupiter

New NASA images support findings that one of Jupiter's stripes that "disappeared" last spring is now showing signs of a comeback. These new observations will help scientists better understand the interaction between Jupiter's winds and cloud chemistry.

Earlier this year, amateur astronomers noticed that a longstanding dark-brown stripe, known as the South Equatorial Belt, just south of Jupiter's equator, had turned white. In early November, amateur astronomer Christopher Go of Cebu City, Philippines, saw an unusually bright spot in the white area that was once the dark stripe. This phenomenon piqued the interest of scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and elsewhere.

Wednesday, December 1, 2010

Planet System May Be Most Populated Yet Found

A densely packed set of planets around a sunlike star located 127 light-years from Earth in the southern constellation Hydrus may be the closest match yet found to our solar system, at least by the numbers, astronomers say. At least five Neptune-like planets have been spotted orbiting the star HD 10180—and there's evidence of two more worlds, one farther from the star and another closer in.

If the latter observations can be confirmed, the innermost planet may hold the record for the lowest-mass extrasolar planet, or exoplanet, seen to date. "We remain cautious about the existence of the innermost and outermost planets," said study lead author Christophe Lovis, an astronomer with the Observatory of Geneva in Switzerland. "But I am confident that at least one of them will be definitively confirmed soon, thus making this system the most populous known so far."

Friday, November 26, 2010

Saturn Moon Has Oxygen Atmosphere

An oxygen atmosphere has been found on Saturn's second largest moon, Rhea, astronomers announced Thursday—but don't hold your breath for colonization opportunities. For one thing, the 932-mile-wide, ice-covered moon is more than 932 million miles from Earth. For another, the average surface temperature is -292 degrees Fahrenheit. Still, the discovery implies that worlds with oxygen-filled air may not be so unusual in the cosmos.

And at less than 62 miles thick, the newfound oxygen layer is so thin that, at Earthlike temperatures and pressure, Rhea's entire atmosphere would fit in a single midsize building. At about 327,000 miles from Saturn, Rhea orbits inside the planet's magnetic field. Rhea's oxygen atmosphere is believed to be maintained by the ongoing chemical breakdown of water ice on the moon's surface, driven by radiation from Saturn's magnetosphere.

Tuesday, November 23, 2010

Brian Marsden, Tracker of Comets, Dies at 73

Brian G. Marsden, who for decades was the go-to guy for thousands of stargazers when a comet or an asteroid would streak through the heavens — or, by his calculations, was supposed to — died Thursday in Burlington, Mass. From 1968 to 2000, Dr. Marsden was director of the archaic-sounding Central Bureau for Astronomical Telegrams, which was founded by the International Astronomical Union in 1920.

In that capacity he was, in effect, the world’s central source of information about the latest astronomical discoveries. As Sky & Telescope magazine said in 1980: “Marsden presides over an international network, including both professional and amateur astronomers, that sends word of the latest discovery winging over the telegraph wires in time for observatories on the other side of the world to catch a nova still brightening, or a new-found comet. As the official certifier of such discoveries, Marsden is probably quoted in newspapers more frequently than any other astronomer in the world.”

Powerful Explosions Can Leave Black Hole Graves

When certain stars collapse, they release overwhelming blasts of energy called gamma-ray bursts – the most powerful explosion in the universe. But the cosmic leftovers of these violent outbursts have been a mystery — until now. Two new studies suggest that when gamma-ray bursts explode, some can leave behind black holes like cosmic gravestones, while others may end up as spinning neutron stars.

Gamma-ray bursts occur when some massive stars reach the ends of their lives and exhaust their supplies of fuel for nuclear fusion in their cores. Without the pressure from fusion pushing outward, gravity wins. In the ensuing dramatic collapse, a flood of high-energy, short-wavelength gamma-ray light is released. They are sometimes associated with supernovas – another explosive way stars die – but are separate events. One of the new studies found that for a certain class of the brightest, most powerful gamma-ray bursts, only black holes will do.

Thursday, November 18, 2010

Full Moons Electrified by Earth's Magnetic "Tail"

Earth's magnetic field creates a protective bubble known as the magnetosphere, which surrounds the planet and shields us from solar wind. The moon's electric charge was discovered by the Kayuga (Selene) lunar orbiter, managed by the Japan Aerospace Exploration Agency (JAXA). Scientists are now mining the data sent back by the craft's imagers and instruments, which recorded that relatively high-energy electrons are being absorbed by the lunar surface when the moon is full.

The result is an electrostatic charge building up in the first few meters above the lunar surface once a month, creating a temporary electric field. Based on Kaguya's data, the team says this lunar electrification happens when the moon passes through the region of the magnetosphere called the plasma sheet, which runs down the middle of Earth's magnetotail. Since the moon has no global magnetic field of its own, its surface remains exposed to the trapped solar particles that are gyrating inside the plasma sheet.

Wednesday, November 17, 2010

Allan Sandage, Astronomer, Dies at 84

Allan R. Sandage, who spent his life measuring the universe, becoming the most influential astronomer of his generation, died Saturday at his home in San Gabriel, Calif. He was 84. The cause was pancreatic cancer, according to an announcement by the Carnegie Observatories, where he had spent his whole professional career.

Over more than six decades, Dr. Sandage was like one of those giant galaxies that sit at the center of a cluster of galaxies, dominating cosmic weather. He wrote more than 500 papers, ranging across the cosmos, covering the evolution and behavior of stars, the birth of the Milky Way galaxy, the age of the universe and the discovery of the first quasar, not to mention the Hubble constant, a famously contested number that measures the rate of expansion of the universe.

Best Time to See the Leonid Meteor Shower

The Leonid meteor shower of 2010 is peaking this week and the best time to see the sky show is now. The annual Leonids should be at their best through Nov. 18, according to skywatching experts. Avid meteor gazers graced with clear skies may see between 15 and 20 meteors per hour.

Skywatchers should look toward the constellation Leo in the eastern sky to see "shooting stars" from the Leonids, which appear to radiate out of the constellation. The best time to try to see the Leonids are in the last two or three hours before sunrise, when the moon has set.

Tuesday, November 16, 2010

Baby Photos of a Black Hole

After watching a nearby star that exploded into a supernova in 1979, astronomers now believe the star's death wasn't an ordinary one. The star's explosion was big enough to cause a black hole to develop in its wake. They think it's a black hole because they see something steadily consuming the gassy remnants of the exploded star, which is a telltale sign of a black hole. It sucks up everything in sight.

And in this case it's a lot. In the past 30 years since this star exploded, this baby black hole has eaten about the equivalent of the Earth in mass, which is about as big as black hole appetites can get, said Harvard astrophysicist Avi Loeb. He's co-author of a new paper in the journal New Astronomy and he discussed the findings at a NASA news conference Monday.

Monday, November 15, 2010

Danish Astronomer's Remains Exhumed in Prague

Astronomer Tycho Brahe uncovered some of the mysteries of the universe in the 16th century — and now modern-day scientists are delving into the mystery of his sudden death. On Monday, an international team of scientists opened his tomb in the Church of Our Lady Before Tyn near Prague's Old Town Square, where Brahe has been buried since 1601. After eight hours of work, they lifted from the tomb a tin box like a child's coffin in which Brahe's remains were placed after the only previous exhumation, in 1901.

Brahe's extraordinarily accurate stellar and planetary observations, which helped lay the foundations of early modern astronomy, are well documented but the circumstances surrounding his death at age 54 are murky. It has been long thought that he died of a bladder infection, but tests conducted in 1996 in Sweden, and later in Denmark, on samples of his mustache and hair obtained in the 1901 exhumation, showed unusually high levels of mercury. That led to a theory of mercury poisoning — even, possibly, murder.

Friday, November 12, 2010

Formation of Bulge on Far Side of Moon Explained

A bulge of elevated topography on the far side of the moon -- known as the lunar far side highlands -- has defied explanation for decades. But a new study led by researchers at the University of California, Santa Cruz, shows that the highlands may be the result of tidal forces acting early in the moon's history when its solid outer crust floated on an ocean of liquid rock.

The paper describes a process for formation of the lunar highlands that involves tidal heating of the moon's crust about 4.4 billion years ago. At that time, not long after the moon's formation, the crust was decoupled from the mantle below it by an intervening ocean of magma. As a result, the gravitational pull of the Earth caused tidal flexing and heating of the crust. At the polar regions, where the flexing and heating was greatest, the crust became thinner, while the thickest crust would have formed in the regions in line with the Earth.

Hubble's Successor May Be Delayed for Years

The James Webb Space Telescope, already billions of dollars over budget and several years behind schedule, will be delayed by at least another year, to 2015, and will cost $1.5 billion more than current estimates, an independent review panel says. Costs and delays could escalate even further if funding for the project does not increase substantially in 2011 and 2012.

Cost estimates have risen for the ambitious mission, billed as the Hubble Space Telescope's heir, since the idea for the telescope was floated in the late 1980s. At that time, proponents estimated that the project would cost about $1 billion. In 2008, NASA officials upped that amount to $5 billion. Though Congress approved all requested funding for JWST in 2009 and 2010, NASA came back asking for an additional $95 million and $20 million in each respective year.

Thursday, November 11, 2010

Mysterious Structures Balloon from Galaxy's Core

Two huge bubbles that emit gamma rays have been found billowing from the center of the Milky Way galaxy, astronomers have announced. The previously unseen structures, detected by NASA's Fermi Gamma-ray Space Telescope, extend 25,000 light-years north and south from the galactic core. For now the source of all that energy is unclear, said study co-author Doug Finkbeiner, an associate professor of astronomy at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA.

The newfound bubbles are made of hot, charged gas that's releasing the same amount of energy as a hundred thousand exploding stars. One possible answer is that the gamma-ray bubbles are evidence of an ancient burst of star formation at the center of the galaxy. If a huge cluster of massive stars formed millions of years ago, the giants could now be dying together, creating an outbreak of supernovae. "Another hypothesis, which is perhaps even more dramatic, is that the [mostly dormant] black hole at the center of the galaxy is active for a little bit," he said.

Friday, November 5, 2010

Deep Impact Spacecraft Flies by Small Comet

A NASA spacecraft sped past a small comet Thursday, beaming pictures back to Earth that gave scientists a rare close-up view of its center. Mission controllers burst into applause upon seeing images from the flyby that revealed a peanut-shaped comet belching jets of poisonous gases. The close encounter occurred 13 million miles from Earth when the Deep Impact craft, hurtling through space, flew within 435 miles of comet Hartley 2. It's only the fifth time that a comet's core has been viewed up close.

Scientists are interested in comets because they're icy leftovers from the formation of the solar system about 4.5 billion years ago. Studying them could provide clues to how Earth and the planets formed and evolved. Thursday's flyby is actually an encore mission for Deep Impact. It set off cosmic fireworks on July 4, 2005, when it fired a copper probe that crashed into comet Tempel 1. The high-speed collision spewed a cloud of debris into space, giving scientists their first peek of the interior.

Tuesday, November 2, 2010

Robot's Space Debut "Giant Leap for Tinmankind"

Space is about to get its first humanoid from planet Earth. Robonaut 2 — affectionately known as R2 — is hitching a one-way ride to the International Space Station this week aboard the final flight of space shuttle Discovery. It's the first humanoid robot ever bound for space, a $2.5 million mechanical and electrical marvel that NASA hopes one day will assist flesh-and-bone astronauts in orbit.

Imagine, its creators say, a future where Robonaut could take over space station cleaning duties; spend hours outside in the extreme heat and cold, patiently holding tools for spacewalking astronauts; and handle emergencies like toxic leaks or fires. For now, R2 — a collaboration between NASA and General Motors — exists only from the waist up. It measures 3 feet 4 inches tall and weighs 330 pounds. Each arm is 2 feet 8 inches long. Legs are still in the works.

Friday, October 29, 2010

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, 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.

Wednesday, October 27, 2010

"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.

Thursday, October 21, 2010

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.

Wednesday, October 20, 2010

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.

Friday, October 15, 2010

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.

Thursday, October 14, 2010

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."

Wednesday, October 6, 2010

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.

Monday, October 4, 2010

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.

Friday, October 1, 2010

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.

Tuesday, September 28, 2010

Potentially Hazardous Object Found by Telescope

The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) PS1 telescope has discovered an asteroid that will come within 4 million miles of Earth in mid-October. The object is about 150 feet in diameter and was discovered in images acquired on September 16, when it was about 20 million miles away. It is the first "potentially hazardous object" (PHO) to be discovered by the Pan-STARRS survey and has been given the designation "2010 ST3."

"Although this particular object won't hit Earth in the immediate future, its discovery shows that Pan-STARRS is now the most sensitive system dedicated to discovering potentially dangerous asteroids," said Robert Jedicke, a University of Hawaii member of the PS1 Scientific Consortium, who is working on the asteroid data from the telescope. Most of the largest PHOs have already been catalogued, but scientists suspect that there are many more under a mile across that have not yet been discovered.

Friday, September 24, 2010

"Coreshine" Sheds Light on the Birth of Stars

Science is literally in the dark when it comes to the birth of stars, which occurs deep inside clouds of gas and dust. These clouds are completely opaque to ordinary light. Now, a group of astronomers has discovered a new astronomical phenomenon that appears to be common in such clouds, and promises a new window onto the earliest phases of star formation. The phenomenon -- infra red light that is scattered by unexpectedly large grains of dust, which the astronomers have termed "coreshine" -- probes the dense cores where stars are born.

Stars are formed as the dense core regions of cosmic clouds of gas and dust ("molecular clouds") collapse under their own gravity. What happens during the earliest phases of this collapse is largely unknown. Enter an international team of astronomers who have discovered a new phenomenon which promises information about the crucial earliest phase of the formation of stars and planets: "coreshine," the scattering of mid-infrared light (which is ubiquitous in our galaxy) by dust grains inside such dense clouds.

Thursday, September 23, 2010

Mercury’s Comet-Like Appearance Spotted

Scientists from Boston University's Center for Space Physics report that NASA satellites designed to view the escaping atmosphere of the Sun have also recorded evidence of escaping gas from the planet Mercury. The STEREO mission has two satellites placed in the same orbit around the Sun that the Earth has, but at locations ahead and behind it.

This configuration offers multi-directional views of the electrons and ions that make up the escaping solar wind. On occasion, the planet Mercury appears in the field of view of one or both satellites. In addition to its appearance as a bright disk of reflected sunlight, a "tail" of emission can be seen in some of the images

Wednesday, September 22, 2010

Primordial Magnetic Fields Found in Deep Space

Scientists from the California Institute of Technology and UCLA have discovered evidence of "universal ubiquitous magnetic fields" that have permeated deep space between galaxies since the time of the Big Bang. Physicists have hypothesized for many years that a universal magnetic field should permeate deep space between galaxies, but there was no way to observe it or measure it until now.

From such blurred images obtained by NASA's Fermi Gamma-Ray Space Telescope, the researchers found that the average magnetic field had a "femto-Gauss" strength, just one-quadrillionth of the Earth's magnetic field. The universal magnetic fields may have formed in the early universe shortly after the Big Bang, long before stars and galaxies formed.

Massive Blast Created Mars' Moon

Scientists say they have uncovered firm evidence that Mars's biggest moon, Phobos, is made from rocks blasted off the Martian surface in a catastrophic event. The origin of Mars's satellites Phobos and Deimos is a long-standing puzzle. It has been suggested that both moons could be asteroids that formed in the main asteroid belt and were then "captured" by Mars's gravity.

The latest evidence supports other scenarios. Material blasted off Mars's surface by a colliding space rock could have clumped together to form the Phobos moon. Alternatively, Phobos could have been formed from the remnants of an earlier moon destroyed by Mars's gravitational forces. However, this moon might itself have originated from material thrown into orbit from the Martian surface.

Monday, September 20, 2010

Closest Encounter with Jupiter until 2022

Jupiter is approaching Earth for the closest encounter between the two planets in more than a decade--and it is dazzling. The night of closest approach is Sept. 20-21st. This is also called "the night of opposition" because Jupiter will be opposite the sun, rising at sunset and soaring overhead at midnight. Among all denizens of the midnight sky, only the Moon itself will be brighter.

Earth-Jupiter encounters happen every 13 months when the Earth laps Jupiter in their race around the sun. But because Earth and Jupiter do not orbit the sun in perfect circles, they are not always the same distance apart when Earth passes by. On Sept. 20th, Jupiter will be as much as 75 million km closer than previous encounters and will not be this close again until 2022.

Friday, September 17, 2010

Pluto Gets 14 New Neighbors

Known collectively as trans-Neptunian objects, or TNOs, the first of this population to be discovered was Pluto in 1930. Since then we've found a thousand or so objects in Pluto's domain. Some have even been given exotic names, such as Chaos, Ixion, Quaoar, and Rhadamanthus. So far, two probes have ventured that deep into the solar system (that'd be Voyager 1 and 2) but neither one paid much heed to TNOs on their way farther afield.

That means astronomers using Earthly telescopes can only guess at how many bodies are out there, what they look like, and what they're made of. Now, using archived pictures from the Hubble Space Telescope, a team of scientists has found a way to spot TNOs, and they've added 14 more to the catalog. The trick to finding them is to look for the equivalent of meteor streaks in Hubble shots of other objects.

"Observe the Moon Night" Tomorrow

This Saturday night people will be gathering in groups around the world to examine Earth's nearest celestial neighbor as part of the first ever International Observe the Moon Night. The global event is a joint project between NASA and several partners to raise awareness about the scientific importance of the moon, such as studying how the solar system formed or planning any future human missions to the lunar surface.

"If we can get people to notice the moon a little more, they might notice it when it's in the news," said Andy Shaner, a spokesperson for the Lunar and Planetary Institute in Houston, which is helping to coordinate the event. Around 370 official events are currently scheduled in nearly 50 countries. But people can have their own moon party from just about anywhere, Shaner said.

New Insights Into the Moon's Geologic Complexity

The moon is more geologically complex than previously thought, scientists report Sept. 17 in two papers published in the journal Science. Their conclusion is based on data from the Diviner Lunar Radiometer Experiment aboard NASA's Lunar Reconnaissance Orbiter (LRO), an unmanned mission to comprehensively map the entire moon. The spacecraft orbits some 31 miles above the moon's surface.

The new data reveal previously unseen compositional differences in the moon's crustal highlands and have confirmed the presence of material surprisingly abundant in silica -- a compound containing the chemical elements silicon and oxygen -- in five distinct lunar regions. For the first time ever, Diviner is providing scientists with global, high-resolution infrared maps of the moon, which are enabling them to make a definitive identification of silicates commonly found within its crust.

Thursday, September 16, 2010

Best View of Comet Hartley 2 Coming Soon

Comet 103P/Hartley 2 was discovered by Australian astronomer Malcolm Hartley in 1986, who calculated that the object orbits the sun about every 6.5 years. Until now, however, gravitational interactions with Jupiter kept shifting the comet's path, sending it closer to the sun and thus farther from Earth during each subsequent return.

This year comet Hartley 2 is on course to make its closest pass by Earth at a mere 11 million miles on October 20—and a dark, moonless sky in mid-October will help create ideal viewing conditions, astronomers say. "Before mid-October, Northern Hemisphere observers will be able to see the comet nearly all night long in the northeast," said Anthony Cook, an astronomer at the Griffith Observatory in California. "After mid-October it can be seen as early as 11:30 p.m. [local time] but is best just before dawn."

Tuesday, September 14, 2010

Chandra Finds Evidence for Stellar Cannibalism

Evidence that a star has recently engulfed a companion star or a giant planet has been found using NASA's Chandra X-ray Observatory. The likely existence of such a "cannibal" star provides new insight into how stars and the planets around them may interact as they age.

The star in question, known as BP Piscium (BP Psc), appears to be a more evolved version of our Sun, but with a dusty and gaseous disk surrounding it. A pair of jets several light years long blasting out of the system in opposite directions has also been seen in optical data. Astronomers have suggested that BP Psc is an old star in its so-called red giant phase. And, rather than being hallmarks of its youth, the disk and jets are, in fact, remnants of a recent and catastrophic interaction whereby a nearby star or giant planet was consumed by BP Psc.