Solar Storm Blasts Electrons from Earth's Van Allen Belts

Scientists say they have solved the mystery of why electrically-charged particles intent in radiation belts thousands of kilometers above the Earth suddenly vanish and then reappear during periods of heightened solar activity.

NASA-funded researchers at the University of California, Los Angeles (UCLA) tracked the electrons using data collected at once with 11 different spacecraft.

Their findings show that when bursts of solar energy released by storms on the sun strike Earth’s magnetic field, they send electrons in the so-called Van Allen radiation belts hurtling into external space. Within a few days, the depleted radiation rings once again swell with a whole new crop of the sun’s highly-charged electrons, which are so active that they move at almost the speed of light.

The UCLA researchers note that the highly charged particles that escape the Van Allen belts forever stream outward, rather than raining down into Earth’s atmosphere as some theories suggest.

The Van Allen belts are a method of bubble-shaped rings of radiation that encircle the planet. Earth's protective magnetic field holds the Van Allen belts in their spot several tens of thousands of kilometers above its surface, and protects the planet from deadly solar, cosmic and other types of space radiation.

The Van Allen belts are named after late NASA astrophysicist James Van Allen, who confirmed occurrence of the radiation rings in 1958. The revolutionary scientist died in 2006 at the age of 91.

An uncertain future for solar system exploration

In less than two weeks, an Atlas V rocket is slated to lift off from Cape Canaveral, propelling NASA’s Mars Science Laboratory (MSL) spacecraft towards the Red Planet. MSL—aka Curiosity—is one of the most ambitious, and expensive, Mars missions ever flown: a rover roughly the size of a Mini Cooper automobile and equipped with a suite of instruments to study Mars and learn about when it was warmer, wetter, and perhaps more hospitable to life. Its landing in August 2012 will be the capstone to what NASA calls the “Year of the Solar System”, a Martian-year-long period that includes milestones ranging from the arrival of MESSENGER at Mercury and Dawn at Vesta to the launches of Juno to Jupiter and GRAIL to the Moon.

While this is something of a golden age for planetary exploration, with a dozen active NASA planetary missions today, there is growing unease in the planetary science community about the future. There were concerns earlier this year with the release of the decadal survey of planetary science missions, which warned of a mismatch between the highest-priority missions—a Mars rover to collect samples for later return to Earth, and a Europa orbiter—and projected budgets ExoMars estrangement

The future of Mars exploration, beyond MSL, had been intended to be one of enhanced collaboration between NASA and ESA. The two agencies had agreed in 2009 to effectively merge NASA’s long-term Mars exploration program with ESA’s ExoMars effort. In 2016 NASA would launch a European Mars orbiter carrying some US instruments, to be followed two years later by the NASA launch of what was originally planned to be separate NASA and ESA Mars rovers, later merged into a single, jointly-developed rover that would cache samples for return to Earth on later missions. That would fulfill the mission of the Mars Astrobiology Explorer-Cacher (MAX-C) that the decadal survey identified earlier this year as the highest priority large, or flagship, planetary science mission in the next decade.
“The Europeans are as mad as hell,” said Hubbard of NASA’s decision not to launch ESA’s 2016 Mars orbiter.

There is evidence, though, that NASA may be backing out of that commitment. In September it informed ESA it would not be able to launch the 2016 European Mars orbiter as planned, forcing ESA officials to scramble to find an alternative approach, one that may have Russia become a partner by launching the orbiter on a Proton rocket. That decision reportedly came at the behest of the Office of Management and Budget (OMB), which also seeks to put the brakes on a joint 2018 mission.

“The Europeans are as mad as hell,” said Scott Hubbard, former director of NASA’s Ames Research Center, at a November 3 Capitol Hill forum on the future of planetary exploration jointly organized by The Mars Society and The Planetary Society. “When I talk to my European colleagues, they’re really, really upset. They feel like they’ve been swindled.”

That frustration comes after NASA and ESA had worked to lower the cost of the 2018 mission. Hubbard said the NASA cost of the mission has been reduced to $1.4 billion, more in line with a midrange New Frontiers mission. “It’s no longer a flagship-class mission,” he said, thanks to $1.2 billion provided by ESA for its role on the mission.

Hubbard believes that OMB may be misinterpreting the “decision rules” included in the planetary science decadal report on how to accommodate reduced budgets. Citing an email from someone who had met with OMB officials about the budget, MAX-C was deemed a “non-starter” by the office under current budgets even with its reduced cost, as it considers flagship missions the lowest priority of all classes of missions.

Hubbard noted that “programmatic balance”—a mix of small, medium-sized, and large missions—was a key aspect of the planetary decadal. That report, moreover, did not place flagship missions as the lowest priority. Instead, it recommended that if costs exceeded projected budgets, flagship missions should be descoped or delayed, followed by changes to the New Frontiers and Discovery programs for smaller missions.

That’s exactly what NASA has done, reducing the cost of MAX-C from its original estimate of $3.5 billion to the new estimate of $1.4 billion. “I would argue that NASA has been extremely responsive to the decadal survey and to budgetary pressure,” Hubbard said.

NASA has said little publicly about the future of its Mars exploration program and cooperation with ESA. At a news briefing last week about the upcoming MSL launch, Doug McCuistion, director of NASA’s Mars program, talked briefly about the issue. “The US and ESA realize we may have some budget concerns in the future, so ESA has approached Russia about potentially providing a launch vehicle and being involved,” he said. He declined to go into more detail because both the fiscal year 2012 budget has yet to be approved by Congress—although that may happen this week—while the 2013 budget proposal won’t be released until early next year. The subject may also come up at a hearing Tuesday on NASA’s planetary science plans by the House Science Committee.

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NASA Space Telescope Finds Fewer Asteroids Near Earth

PASADENA, Calif. -- New observations by NASA's Wide-field Infrared Survey Explorer, or WISE, show there are significantly fewer near-Earth asteroids in the mid-size range than previously thought. The findings also indicate NASA has found more than 90 percent of the largest near-Earth asteroids, meeting a goal agreed to with Congress in 1998.

Astronomers now estimate there are roughly 19,500 -- not 35,000 -- mid-size near-Earth asteroids. Scientists say this improved understanding of the population may indicate the hazard to Earth could be somewhat less than previously thought. However, the majority of these mid-size asteroids remain to be discovered. More research also is needed to determine if fewer mid-size objects (between 330 and 3,300-feet wide) also mean fewer potentially hazardous asteroids, those that come closest to Earth.

The results come from the most accurate census to date of near-Earth asteroids, the space rocks that orbit within 120 million miles (195 million kilometers) of the sun into Earth's orbital vicinity. WISE observed infrared light from those in the middle to large-size category. The survey project, called NEOWISE, is the asteroid-hunting portion of the WISE mission. Study results appear in the Astrophysical Journal.

"NEOWISE allowed us to take a look at a more representative slice of the near-Earth asteroid numbers and make better estimates about the whole population," said Amy Mainzer, lead author of the new study and principal investigator for the NEOWISE project at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It's like a population census, where you poll a small group of people to draw conclusions about the entire country."

WISE scanned the entire celestial sky twice in infrared light between January 2010 and February 2011, continuously snapping pictures of everything from distant galaxies to near-Earth asteroids and comets. NEOWISE observed more than 100 thousand asteroids in the main belt between Mars and Jupiter, in addition to at least 585 near Earth.

WISE captured a more accurate sample of the asteroid population than previous visible-light surveys because its infrared detectors could see both dark and light objects. It is difficult for visible-light telescopes to see the dim amounts of visible-light reflected by dark asteroids. Infrared-sensing telescopes detect an object's heat, which is dependent on size and not reflective properties.

Though the WISE data reveal only a small decline in the estimated numbers for the largest near-Earth asteroids, which are 3,300 feet (1 kilometer) and larger, they show 93 percent of the estimated population have been found. This fulfills the initial "Spaceguard" goal agreed to with Congress. These large asteroids are about the size of a small mountain and would have global consequences if they were to strike Earth. The new data revise their total numbers from about 1,000 down to 981, of which 911 already have been found. None of them represents a threat to Earth in the next few centuries. It is believed that all near-Earth asteroids approximately 6 miles (10 kilometers) across, as big as the one thought to have wiped out the dinosaurs, have been found.

"The risk of a really large asteroid impacting the Earth before we could find and warn of it has been substantially reduced," said Tim Spahr, the director of the Minor Planet Center at the Harvard Smithsonian Center for Astrophysics in Cambridge, Mass.

The situation is different for the mid-size asteroids, which could destroy a metropolitan area if they were to impact in the wrong place. The NEOWISE results find a larger decline in the estimated population for these bodies than what was observed for the largest asteroids. So far, the Spaceguard effort has found and is tracking more than 5,200 near-Earth asteroids 330 feet or larger, leaving more than an estimated 15,000 still to discover. In addition, scientists estimate there are more than a million unknown smaller near-Earth asteroids that could cause damage if they were to impact Earth.

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Dawn Team Members Check out Spacecraft

Dawn Mission Status Update

Mission managers for NASA's Dawn spacecraft are studying the spacecraft's ion propulsion system after Dawn experienced a loss of thrust on June 27. Dawn team members were able to trace the episode to an electronic circuit in the spacecraft's digital control and interface unit, a subsystem that houses the circuit and a computer that provides the "brains" to Dawn's ion propulsion system. That circuit appeared to lose an electronic signal. As a result, the valves controlling the flow of xenon fuel did not open properly. Dawn automatically put itself into a more basic configuration known as "safe-communications" mode, where the spacecraft stopped some activities and turned its high-gain antenna to Earth.

Engineers were able to return the spacecraft to a normal configuration and restart the spacecraft's thrusting on June 30 by switching to a second digital control and interface unit with equivalent capabilities. One set of images for navigation purposes was not obtained on June 28 because the spacecraft was in safe-communications mode, and one other set, on July 6, was not obtained to allow the spacecraft to spend the time thrusting. Other sets of navigation images have been and will be acquired as expected. The ion propulsion system is now functioning normally.

"Dawn is still on track to get into orbit around Vesta, and thanks to the flexibility provided by our use of ion propulsion, the time of orbit capture actually will move earlier by a little less than a day," said Marc Rayman, Dawn's chief engineer and mission manager. "More importantly, the rest of Dawn's schedule is unaffected, and science collection is expected to begin as scheduled in early August."

In an unrelated event, the visible and infrared mapping spectrometer on Dawn reset itself on June 29. At the time of the reset, the instrument was gathering calibration data during the spacecraft's approach to the giant asteroid Vesta. Some of its planned observations were completed successfully before automatic sensors turned the instrument off.

On June 30, Dawn team members were able to trace the reset to an internal error in the instrument's central processing unit, though they don't yet know why the internal error occurred. By temporarily turning the instrument back on, the Dawn team confirmed that the instrument is otherwise in a normal configuration. They powered the instrument back off, as originally planned for this time. Team members are working to determine when they will turn it back on again.

After arriving at Vesta, Dawn will spend about one year orbiting the asteroid, which is also known as a protoplanet because it is a large body that almost became a planet. Data collected at Vesta will help scientists understand the earliest chapter of our solar system's history.

The Dawn mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. The University of California, Los Angeles, is responsible for overall Dawn mission science. Other scientific partners include Planetary Science Institute, Tucson, Ariz.; Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany; DLR Institute for Planetary Research, Berlin, Germany; Italian National Institute for Astrophysics, Rome; and the Italian Space Agency, Rome. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft.

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NASA's Spitzer Finds Distant Galaxies Grazed on Gas

PASADENA, Calif. -- Galaxies once thought of as voracious tigers are more like grazing cows, according to a new study using NASA's Spitzer Space Telescope.

Astronomers have discovered that galaxies in the distant, early universe continuously ingested their star-making fuel over long periods of time. This goes against previous theories that the galaxies devoured their fuel in quick bursts after run-ins with other galaxies.

"Our study shows the merging of massive galaxies was not the dominant method of galaxy growth in the distant universe," said Ranga-Ram Chary of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena, Calif. "We're finding this type of galactic cannibalism was rare. Instead, we are seeing evidence for a mechanism of galaxy growth in which a typical galaxy fed itself through a steady stream of gas, making stars at a much faster rate than previously thought."

Chary is the principal investigator of the research, appearing in the Aug. 1 issue of the Astrophysical Journal. According to his findings, these grazing galaxies fed steadily over periods of hundreds of millions of years and created an unusual amount of plump stars, up to 100 times the mass of our sun.

"This is the first time that we have identified galaxies that supersized themselves by grazing," said Hyunjin Shim, also of the Spitzer Science Center and lead author of the paper. "They have many more massive stars than our Milky Way galaxy."

Galaxies like our Milky Way are giant collections of stars, gas and dust. They grow in size by feeding off gas and converting it to new stars. A long-standing question in astronomy is: Where did distant galaxies that formed billions of years ago acquire this stellar fuel? The most favored theory was that galaxies grew by merging with other galaxies, feeding off gas stirred up in the collisions.

Chary and his team addressed this question by using Spitzer to survey more than 70 remote galaxies that existed 1 to 2 billion years after the Big Bang (our universe is approximately 13.7 billion years old). To their surprise, these galaxies were blazing with what is called H alpha, which is radiation from hydrogen gas that has been hit with ultraviolet light from stars. High levels of H alpha indicate stars are forming vigorously. Seventy percent of the surveyed galaxies show strong signs of H alpha. By contrast, only 0.1 percent of galaxies in our local universe possess this signature.

Previous studies using ultraviolet-light telescopes found about six times less star formation than Spitzer, which sees infrared light. Scientists think this may be due to large amounts of obscuring dust, through which infrared light can sneak. Spitzer opened a new window onto the galaxies by taking very long-exposure infrared images of a patch of sky called the GOODS fields, for Great Observatories Origins Deep Survey.

Further analyses showed that these galaxies furiously formed stars up to 100 times faster than the current star-formation rate of our Milky Way. What's more, the star formation took place over a long period of time, hundreds of millions of years. This tells astronomers that the galaxies did not grow due to mergers, or collisions, which happen on shorter timescales. While such smash-ups are common in the universe -- for example, our Milky Way will merge with the Andromeda galaxy in about 5 billion years -- the new study shows that large mergers were not the main cause of galaxy growth. Instead, the results show that distant, giant galaxies bulked up by feeding off a steady supply of gas that probably streamed in from filaments of dark matter.

Chary said, "If you could visit a planet in one of these galaxies, the sky would be a crazy place, with tons of bright stars, and fairly frequent supernova explosions."

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer Space Telescope mission for the agency's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech. Caltech manages JPL for NASA.

NASA SAYS SUN AND PLANETS CONSTRUCTED DIFFERENTLY

PASADENA, Calif. - Researchers analyzing samples returned by NASA's 2004 Genesis mission have discovered that our sun and its inner planets may have formed differently than previously thought.

Data revealed differences between the sun and planets in oxygen and nitrogen, which are two of the most abundant elements in our solar system. Although the difference is slight, the implications could help determine how our solar system evolved.

"We found that Earth, the moon, as well as Martian and other meteorites which are samples of asteroids, have a lower concentration of the O-16 than does the sun," said Kevin McKeegan, a Genesis co-investigator from UCLA, and the lead author of one of two Science papers published this week. "The implication is that we did not form out of the same solar nebula materials that created the sun -- just how and why remains to be discovered."

The air on Earth contains three different kinds of oxygen atoms which are differentiated by the number of neutrons they contain. Nearly 100 percent of oxygen atoms in the solar system are composed of O-16, but there are also tiny amounts of more exotic oxygen isotopes called O-17 and O-18. Researchers studying the oxygen of Genesis samples found that the percentage of O-16 in the sun is slightly higher than on Earth or on other terrestrial planets. The other isotopes' percentages were slightly lower.

Another paper detailed differences between the sun and planets in the element nitrogen. Like oxygen, nitrogen has one isotope, N-14, that makes up nearly 100 percent of the atoms in the solar system, but there is also a tiny amount of N-15. Researchers studying the same samples saw that when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition. As is the case for oxygen, Earth and the rest of the inner solar system are very different in nitrogen.

"These findings show that all solar system objects including the terrestrial planets, meteorites and comets are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co-investigator from Centre de Recherches Pétrographiques et Géochimiques and the lead author of the other new Science paper. "Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system."

Data were obtained from analysis of samples Genesis collected from the solar wind, or material ejected from the outer portion of the sun. This material can be thought of as a fossil of our nebula because the preponderance of scientific evidence suggests that the outer layer of our sun has not changed measurably for billions of years.

"The sun houses more than 99 percent of the material currently in our solar system, so it's a good idea to get to know it better," said Genesis Principal Investigator Don Burnett of the California Institute of Technology, Pasadena, Calif. "While it was more challenging than expected, we have answered some important questions, and like all successful missions, generated plenty more."

Genesis launched in August 2000. The spacecraft traveled to Earth's L1 Lagrange Point about 1 million miles from Earth, where it remained for 886 days between 2001 and 2004, passively collecting solar-wind samples.

On Sept. 8, 2004, the spacecraft released a sample return capsule, which entered Earth's atmosphere. Although the capsule made a hard landing as a result of a failed parachute in the Utah Test and Training Range in Dugway, Utah, it marked NASA's first sample return since the final Apollo lunar mission in 1972, and the first material collected beyond the moon. NASA's Johnson Space Center in Houston curates the samples and supports analysis and sample allocation.

The Jet Propulsion Laboratory, Pasadena, Calif., managed the Genesis mission for NASA's Science Mission Directorate, Washington. The Genesis mission was part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, developed and operated the spacecraft. Analysis at the Centre de Recherches Pétrographiques et Géochimiques, Nancy, France, was supported by the Centre National d'Etudes Spatiales, Paris, and the Centre National de la Recherche Scientifique, Paris, France.

Astronomers Find Newly Discovered Asteroid Is Earth's Companion

Astronomers from the Armagh Observatory in Northern Ireland have found that a recently discovered asteroid has been following Earth in its motion around the Sun for at least the past 250,000 years, and may be intimately related to the origin of our planet.

The asteroid first caught the eye of the scientists, Apostolos "Tolis" Christou and David Asher, two months after it was found by the WISE infrared survey satellite, launched in 2009 by the United States. "Its average distance from the Sun is identical to that of the Earth,", "but what really impressed me at the time was how Earth-like its orbit was." Most near-Earth Asteroids -- NEAs for short -- have very eccentric, or egg-shaped, orbits that take the asteroid right through the inner solar system. But the new object, designated 2010 SO16, is different. Its orbit is almost circular so that it cannot come close to any other planet in the solar system except Earth.

The researchers set out to investigate how stable this orbit is and how long the asteroid has occupied it. To do that, they first had to take into account the current uncertainty in the asteroid's orbit. "Not knowing precisely the location of a newly-discovered NEA is quite common," explained Dr Asher. "The only way to eliminate the uncertainty is to keep tracking the asteroid for as long as possible, usually months or years." But the two scientists overcame that problem by creating virtual "clones" of the asteroid for every possible orbit that it could conceivably occupy. They then simulated the evolution of these clones under the gravity of the Sun and the planets for two million years into the past and in the future.

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Comet Elenin: Preview of a Coming Attraction

Comet Elenin, was first detected on Dec. 10, 2010 by Leonid Elenin, an observer in Lyubertsy, Russia, who made the discovery "remotely" using the ISON-NM observatory near Mayhill, New Mexico. At the time of the discovery, the comet was about 647 million kilometers from Earth. Over the past four-and-a-half months, the comet has - as comets do - closed the distance to Earth's vicinity as it makes its way closer to perihelion. As of May 4, Elenin's distance is about 274 million kilometers.

"That is what happens with these long-period comets that come in from way outside our planetary system," said Don Yeomans of NASA's Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "They make these long, majestic, speedy arcs through our solar system, and sometimes they put on a great show. But not Elenin. Right now that comet looks kind of wimpy."

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Mars Express Sees Deep Fractures on Mars

Newly released images from the European Space Agency's Mars Express show Nili Fossae, a system of deep fractures around the giant Isidis impact basin. Some of these incisions into the martian crust are up to 500 m deep and probably formed at the same time as the basin.

Nili Fossae is a 'graben' system on Mars, northeast of the Syrtis Major volcanic province, on the northwestern edge of the giant Isidis impact basin. Graben refers to the lowered terrain between two parallel faults or fractures in the rocks that collapses when tectonic forces pull the area apart. The Nili Fossae system contains numerous graben concentrically oriented around the edges of the basin.

It is thought that flooding of the basin with basaltic lava after the impact that created it resulted in subsidence of the basin floor, adding stress to the planet's crust, which was released by the formation of the fractures.

A strongly eroded impact crater is visible to the bottom right of the image. It measures about 12 km across and exhibits an ejecta blanket, usually formed by material thrown out during the impact. Two landslides have taken place to the west of the crater. Whether they were a direct result of the impact or occurred later is unknown.

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Mars Tribute Marks Memories of Shepard's Flight

The team exploring Mars via NASA's Opportunity rover for the past seven years has informally named a Martian crater for the Mercury spacecraft that astronaut Alan Shepard christened Freedom 7. On May 5, 1961, Shepard piloted Freedom 7 in America's first human spaceflight.

The team is using Opportunity this week to acquire images covering a cluster of small, relatively young craters along the rover's route toward a long-term destination. The cluster's largest crater, spanning about 25 meters , is the one called "Freedom 7." The diameter of Freedom 7 crater, about 25 meters, happens to be equivalent to the height of the Redstone rocket that launched Shepard's flight.

"Many of the people currently involved with the robotic investigations of Mars were first inspired by the astronauts of the Mercury Project who paved the way for the exploration of our solar system," said Scott McLennan of the State University of New York at Stony Brook, who is this week's long-term planning leader for the rover science team. Shepard's flight was the first of six Project Mercury missions piloted by solo astronauts.

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Dawn Reaches Milestone Approaching Asteroid Vesta

NASA's Dawn spacecraft has reached its official approach phase to the asteroid Vesta and will begin using cameras for the first time to aid navigation for an expected July 16 orbital encounter. The large asteroid is known as a protoplanet – a celestial body that almost formed into a planet.

At the start of this three-month final approach to this massive body in the asteroid belt, Dawn is 1.21 million kilometers (752,000 miles) from Vesta, or about three times the distance between Earth and the moon. During the approach phase, the spacecraft's main activity will be thrusting with a special, hyper-efficient ion engine that uses electricity to ionize and accelerate xenon. The 12-inch-wide ion thrusters provide less thrust than conventional engines, but will provide propulsion for years during the mission and provide far greater capability to change velocity. "We feel a little like Columbus approaching the shores of the New World," said Christopher Russell, Dawn principal investigator, based at the University of California in Los Angeles (UCLA). "The Dawn team can't wait to start mapping this Terra Incognita."

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Plasmoids and Sheaths Mean Success or Failure for Solar Eruptions

Our Sun experiences regular eruptions of material into space, but solar physicists still have difficulty in explaining why these dramatic events take place. Now a group of scientists from the University of St Andrews think they have the answer: clouds of plasma constrained by magnetic fields and known as 'plasmoids' that struggle to break free of the Sun's magnetic field.

Active regions on the solar surface are often the site of eruptions. These are associated with magnetic fields from the solar interior rising to the surface and gradually expanding into the Sun's outer atmosphere, the corona, in a process known as magnetic flux emergence. The St Andrews team developed 3D computer models of these phenomena, revealing that the emergence of magnetic flux naturally leads to the formation and expulsion of plasmoids that adopt a twisted tube configuration.

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NASA's Swift and Hubble Probe Asteroid Collision Debris

Data from NASA's Swift satellite and Hubble Space Telescope showed these changes likely occurred after Scheila was struck by a much smaller asteroid. "Collisions between asteroids create rock fragments, from fine dust to huge boulders, that impact planets and their moons," said Dennis Bodewits, an astronomer at the University of Maryland in College Park and lead author of the Swift study. "Yet this is the first time we've been able to catch one just weeks after the smash-up, long before the evidence fades away."

Asteroids are rocky fragments thought to be debris from the formation and evolution of the solar system approximately 4.6 billion years ago. Millions of them orbit the sun between Mars and Jupiter in the main asteroid belt. Scheila is approximately 70 miles across and orbits the sun every five years."The Hubble data are most simply explained by the impact, at 11,000 mph, of a previously unknown asteroid about 100 feet in diameter," said Hubble team leader David Jewitt at the University of California in Los Angeles. Hubble did not see any discrete collision fragments, unlike its 2009 observations of P/2010 A2, the first identified asteroid collision.

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Voyager Probes Set to Enter Interstellar Space

NASA's twin Voyager probes are now at the edge of the solar system. Not only that, they're still working. And with each passing day they are beaming back a message that, to scientists, is both unsettling and thrilling. "It's uncanny," says Ed Stone of the California Institute of Technology in Pasadena, Voyager Project Scientist since 1972. "Voyager 1 and 2 have a knack for making discoveries." Today, April 28, 2011, NASA held a live briefing to reflect on what the Voyager mission has accomplished--and to preview what lies ahead as the probes prepare to enter the realm of interstellar space in our Milky Way galaxy.

The adventure began in the late 1970s when the probes took advantage of a rare alignment of outer planets for an unprecedented Grand Tour. Voyager 1 visited Jupiter and Saturn, while Voyager 2 flew past Jupiter, Saturn, Uranus and Neptune.

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Austrian Space Forum Successfully Tests Mars Suit ‘Aouda.X’ in Spain

A team from the Austrian Space Forum is arriving back in Austria April 25, 2011 following a week testing its analogue space suit 'Aouda.X' in the semi-desert of Rio Tinto in Spain. This suit has been developed by the Austrian Space Forum over three years and is one of the best models of its kind worldwide.

The European Space Agency (ESA) also participated in this mission with the Mars rover 'Eurobot'. This 1.5 million Euro prototype was been transported from the Netherlands to Spain and passed its first test under field conditions on April 19. Valuable scientific and technical data have been collected between during the tests, which ran from April 18 to 21. Aouda.X and Eurobot completed several activities together, demonstrating it was possible to test the man-machine-interface, which will play a vital role in a real Mars mission.

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Huge Dry Ice Deposit on Mars: NASA Orbiter Reveals Big Changes in Red Planet's Atmosphere

NASA's Mars Reconnaissance Orbiter has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet's axis varies. This process can affect the stability of liquid water, if it exists on the Martian surface, and increase the frequency and severity of Martian dust storms.

Researchers using the orbiter's ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet's south pole. The scientists suspect that much of this carbon dioxide enters the planet's atmosphere and swells the atmosphere's mass when Mars' tilt increases. The findings are published in the journal Science.

The newly found deposit has a volume similar to Lake Superior's nearly 3,000 cubic miles. The deposit holds up to 80 percent as much carbon dioxide as today's Martian atmosphere. Collapse pits caused by dry ice sublimation and other clues suggest the deposit is in a dissipating phase, adding gas to the atmosphere each year. Mars' atmosphere is about 95 percent carbon dioxide, in contrast to Earth's much thicker atmosphere, which is less than .04 percent carbon dioxide.

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Beams of Electrons Link Saturn With Its Moon Enceladus

Data from NASA's Cassini spacecraft have revealed that Enceladus, one of Saturn's diminutive moons, is linked to Saturn by powerful electrical currents -- beams of electrons that flow back and forth between the planet and moon. one of the instruments on board Cassini which made the electron beam discovery, includes a electron sensor called CAPS-ELS -- led by UCL (University College London).

Since Cassini's arrival at Saturn in 2004 it has passed 500km-wide Enceladus 14 times, gradually discovering more of its secrets on each visit. Research has found that jets of gas and icy grains emanate from the south pole of Enceladus, which become electrically charged and form an ionosphere. The motion of Enceladus and its ionosphere through the magnetic bubble that surrounds Saturn acts like a dynamo, setting up the newly-discovered current system.

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Astronomers Can Tune in to Radio Auroras to Find Exoplanets

scientists at the University of Leicester have shown that emissions from the radio aurora of planets like Jupiter should be detectable by radio telescopes such as LOFAR, which will be completed later this year. Dr Jonathan Nichols will present results at the RAS National Astronomy Meeting in Llandudno, Wales, on April 18.

"This is the first study to predict the radio emissions by exoplanetary systems similar to those we find at Jupiter or Saturn. At both planets, we see radio waves associated with auroras generated by interactions with ionised gas escaping from the volcanic moons, Io and Enceladus. Our study shows that we could detect emissions from radio auroras from Jupiter-like systems orbiting at distances as far out as Pluto," said Nichols.

Of the hundreds of exoplanets that have been detected to date, less than 10% orbit at distances where we find the outer planets in our own Solar System. Most exoplanets have been found by the transit method, which detects a dimming in light as a planet moves in front of a star, or by looking for a wobble as a star is tugged by the gravity of an orbiting planet. With both these techniques, it is easiest to detect planets close in to the star and moving very quickly.

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Solar Activity Heats Up: Sunspots Finally Return

If you've ever stood in front of a hot stove, watching a pot of water and waiting impatiently for it to boil, you know what it feels like to be a solar physicist. Back in 2008, the solar cycle plunged into the deepest minimum in nearly a century. Sunspots all but vanished, solar flares subsided, and the sun was eerily quiet.

"Ever since, we've been waiting for solar activity to pick up," says Richard Fisher, head of the Heliophysics Division at NASA Headquarters in Washington DC. "It's been three long years." Quiet spells on the sun are nothing new. They come along every 11 years or so, it's a natural part of the solar cycle. This particular solar minimum, however, was lasting longer than usual, prompting some researchers to wonder if it would ever end.

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Fast-Rotating Asteroid Winks For Astronomer's Camera

Video imaging of newly discovered asteroid 2011 GP59 shows the object appearing to blink on and off about once every four minutes. Amateur astronomers, including Nick James of Chelmsford, Essex, England, have captured video of the interesting object. James generated this video of GP59 on the night of Monday, April 11. The video, captured with an 11-inch Schmidt-Cassegrain telescope, is a compilation of 137 individual frames, each requiring 30 seconds of exposure. At the time, the asteroid was approximately 3,356,000 kilometers distant.

"Usually, when we see an asteroid strobe on and off like that, it means that the body is elongated and we are viewing it broadside along its long axis first, and then on its narrow end as it rotates ," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "GP59 is approximately 50 meters [240 feet] long, and we think its period of rotation is about seven-and-a-half minutes. This makes the object's brightness change every four minutes or so." 2011 GP59 was discovered the night of April 8/9 by astronomers with the Observatorio Astronomico de Mallorca in Andalusia, Spain. It will make its closest approach to Earth on April 15 at 19:09 UTC (12:09 p.m. PDT) at a distance just beyond the moon's orbit - about 533,000 kilometers.