2013년 7월 31일 수요일

Astronaut Drives Rover from Space Station

An astronaut aboard the International Space Station successfully operated a rover on Earth's surface Friday (July 26), helping lay the foundation for future human-robot partnerships that could push the boundaries of planetary exploration.
While zipping around Earth several hundred miles above the planet's surface, European Space Agency astronaut Luca Parmitano drove a 220-pound (100 kilograms) rover across a moon-mimicking landscape here at NASA's Ames Research Center, even ordering the robot to deploy a simulated film-based radio telescope antenna.
Friday's test was the second in a three-part series designed to help engineers and mission planners understand how the activities of humans and robots can be coordinated to maximize the reach and efficiency of planetary exploration missions. (The first run took place June 17 here at Ames, and the third is slated to occur next month.)
- See more at: http://www.space.com/22160-space-station-astronaut-drives-rover.html#sthash.CvAVVnbZ.dpuf

"I think that the future of exploration is such that you'll have to have both humans and robots working together," said Terry Fong, human exploration telerobotics project manager and director of the Intelligent Robotics Group at Ames, which designed and manages the tests. - See more at: http://www.space.com/22160-space-station-astronaut-drives-rover.html#sthash.CvAVVnbZ.dpuf

"It doesn't necessarily mean humans and robots always closely coupled in space or even time; you could have robots working ahead of humans, robots working in parallel, robots following up," Fong told SPACE.com. "But part of that is really trying to understand, well, if you're going to build these systems, what do you need? How do you build them?"
The tests at Ames simulate a mission in which astronauts parked at Earth-moon Lagrange point 2 — a gravitationally stable spot located about 40,000 miles (64,000 kilometers) above the moon's surface — operate a rover on the lunar farside.

Such a mission would have many benefits, advocates say. For example, the rover could deploy a radio telescope antenna, which would return great data to astronomers thanks to the "quiet zone" found on the moon's farside. The teleoperated rover could also collect ancient farside rocks for delivery back to labs on Earth.

"The twofer that you would get out of this for science is pretty exciting," said Jack Burns, director of the Lunar University Network for Astrophysics Research at the University of Colorado, Boulder, which developed the mission concept.
Burns hopes such a mission will launch in 2021, on the first manned flight of NASA's Orion capsule and Space Launch System rocket. The tests at Ames — which use the four-wheel, 4.5-foot-tall (1.4 meters) K10 rover — are steps toward making that dream come true, he said.

"We have demonstrated for the first time that an astronaut can operate a rover and do some relatively sophisticated commands," Burns told SPACE.com. "It's baby steps, but it's a good set of baby steps."

Source of Article: Space.com

Comet ISON: Is Potential 'Comet of the Century' Already Fizzling Out?

It doesn't look like Comet ISON will live up to the considerable hype, one researcher says.
ISON has been billed as a potential "comet of the century," with some experts saying it could blaze as brightly as the full moon around the time of its close solar approach in late November. But the comet's recent behavior suggests that such a dazzling show is not in the cards, says astronomer Ignacio Ferrín of the University of Antioquia in Medellín, Colombia.
"Comet ISON has presented a peculiar behavior," Ferrín said in a statement Monday (July 29). "The light curve has exhibited a 'slowdown event' characterized by a constant brightness, with no indication of a brightness increase tendency. This slowdown took place around January 13th, 2013. For 132 days after that date and up to the last available observation, the brightness has remained constant."

Comet ISON's recent performance has a precedent that's not terribly encouraging. In 2003, Comet C/2002 O4 Hönig exhibited a brightness plateau for 52 days and then disintegrated, Ferrín noted.

"The future of Comet ISON does not look bright," he said.

Comet ISON is slated to skim just 724,000 miles (1.16 million kilometers) above the surface of the sun on Nov. 28. Thus far, most scientists have been hedging their bets about the icy wanderer's performance. It's difficult to predict how any comet will behave during a close solar passage, they say, and especially tough to do so for "dynamically new" comets like ISON that are making their first trip to the inner solar system from the frigid, distant Oort Cloud.

The forecast could start firming up a bit soon, however. Comet ISON — whose nucleus is thought to be just 3 to 4 miles (4.8 to 6.5 km) wide — is slated to cross the "frost line" within the next few weeks, scientists say.

This boundary, which lies about 230 to 280 million miles (370 to 450 million km) from the sun, marks the point at which ISON's water ice will start boiling off into space. (Until now, most of its activity has been driven by sublimating carbon dioxide.)

ISON should brighten as it crosses the frost line, and scientists and skywatchers should get a better idea of how tough the comet is, researchers say. Some inbound comets haven't survived their trip past the frost line.

Comet ISON was discovered last September by amateur astronomers Vitali Nevski and Artyom Novichonok. It takes its name from the equipment the duo used — the International Scientific Optical Network (ISON) near Kislovodsk, Russia.

Skywatchers aren't the only people eagerly tracking ISON's journey toward the sun. NASA has organized a coordinated observation campaign enlisting many instruments on the ground and in space. The goal is to learn more about Comet ISON's composition, which could in turn reveal insights about the early days of the solar system.

Source of Article: Space.com

Wobbly, Sunlike Star Being Pulled by Giant Alien Planet

By analyzing sonic vibrations in a distant sunlike star, astronomers might have calculated exactly how fast the star spins and how much a nearby giant alien planet weighs.
Stars, including the sun, experience sound waves that zip around inside them and cause tiny rhythmic fluctuations in their brightness. By studying these variations, scientists can better understand the interiors of stars— an emerging scientific field known as asteroseismology that is akin to seismology on Earth, which helps geologists yield insights into the innards of this planet.
Scientists used the COROT satellite to analyze the sunlike star HD 52265, located more than 90 light-years from Earth in the constellation Monoceros, the Unicorn. The star, which has a mass about 1.2 times that of the sun and a diameter 1.3 times greater than the sun's, is about 2.1 billion to 2.7 billion years old.

Repeated wobbles in the movements of HD 52265 suggested a giant planet's gravitational pull was tugging on it, which astronomers dubbed HD 52265b. The magnitude of the wobbles suggested the planet had a mass at least 1.09 times that of Jupiter — scientists could not give a more precise figure based on the wobbles alone.
The oscillations in brightness that the researchers investigated are linked to ripples in that star that are, in turn, based in part on its rate of rotation. The scientists calculated HD 52265's interior completes a revolution every 12 days, meaning it revolves some 2.3 times faster than the sun.
"Knowing the rotation of stars is important to understand stellar activity cycles," said Laurent Gizon, an astrophysicist at the Max Planck Institute for Solar System Research in Germany and the study's lead author. "Magnetic fields in stars like the sun are maintained by rotation and convection."
Discovering the manner in which the star HD 52265 rotates also provides clues about how the planet HD 52265b is oriented toward it, assuming the star's equator is lined up with the planet's, as is typically the case in Earth's solar system. When these data are combined with the information about the magnitude of the wobbles the planet exerts on its star, the mass of world is about 1.85 times the mass of Jupiter, the researchers calculated.
"Asteroseismology is a very powerful technique to fully characterize exoplanets," Gizon said.
In the future, the European Space Agency's PLATO mission could use asteroseismology to analyze a multitude of stars and planets.
"The decision on the selection of the mission is expected at the beginning of 2014," Gizon said.

Source of Article: Space.com

SpaceX Wins Contract to Launch Canadian Radar Satellites

Space Exploration Technologies Corp. (SpaceX) will launch all three satellites for Canada’s planned Radarsat Constellation Mission (RCM) in 2018 aboard a single Falcon 9 rocket, the Hawthorne, Calif., rocket maker announced Tuesday (July 30).
The contract award to SpaceX had been expected since January, when the Canadian Space Agency awarded MDA Corp. of Richmond, British Columbia, the 706 million Canadian dollar ($692 million) prime contract to build the RCM satellites.
Final terms of SpaceX’s "launch reservation" contact, which was awarded by MDA Corp., were not disclosed. 

In addition to building the satellites, MDA will market the radar imagery they collect. The RCM satellites will collect radar imagery at resolutions as sharp as 3.3 feet (1 meter), enough to discern objects of that size or larger, for a variety of applications that will include Arctic and maritime surveillance and disaster monitoring.
SpaceX is expected to launch its first MDA-built satellite, an experimental multimission satellite dubbed Cassiope, this year. That launch will be the first of SpaceX’s Falcon 9 v1.1 upgrade, which features a new engine design and payload fairing and will be used on subsequent missions to launch commercial satellites to geostationary transfer orbit. 
"SpaceX appreciates MDA’s confidence in our ability to safely and reliably transport their satellites," SpaceX president and chief operating officer Gwynne Shotwell said in a statement Tuesday. "We hope this agreement is the second of many with MDA."

Source of Article: Space.com

2013년 7월 29일 월요일

NASA Flooded with Asteroid Exploration Ideas

A NASA call for novel ideas on how to tackle its ambitious mission to capture an asteroid and park it near the moon has paid off in spades, with the agency receiving hundreds of proposals from potential partners.
NASA has received more than 400 proposals from private companies, non-profit groups and international organizations in response to a call for asteroid-retrieval mission suggestions released last month, agency officials announced Friday (July 26). The space agency will review the submissions over the next month and plan to discuss the most promising ideas in a public workshop in September.  
"We are really excited about the overwhelming response," NASA Deputy Administrator Lori Garver told reporters here at the NewSpace 2013 conference, adding that the ideas were "overwhelmingly positive."

NASA put out an official request for information on June 18 to seek input on how to achieve its asteroid retrieval mission. That asteroid capture plan, which NASA unveiled in April, is known as the agency's Asteroid Initiative.

The NASA asteroid retrieval mission aims to send a robotic spacecraft out to a near-Earth asteroid, snare it with a "space lasso" and tow it back to a parking orbit near the moon so it can be explored by astronauts. The asteroid mission is NASA's way of pursuing the goal set by President Barack Obama that called on NASA to send a manned mission to a near-Earth asteroid by 2025, and then aim for a Mars flight in the 2030s.

On June 18, NASA also unveiled its Asteroid Grand Challenge, an effort to find and identify all of the asteroids that could pose a threat to Earth, as well as develop ideas to defend the planet against potential impacts. The effort is one of several national "grand challenges" announced by the Obama Administration and other government agencies in recent weeks to spur scientific progress and innovation.

"Under our plan, we're increasing the identification, tracking and exploration of asteroids, and the response to this initiative has been gratifying," Garver told an audience of private spaceflight experts and enthusiasts at the NewSpace conference here. "The aerospace industry, innovative small businesses and citizen scientists have many creative ideas and strategies for carrying out our asteroid exploration mission and helping us to protect our home planet from dangerous near-Earth objects."

About one-third of the 400 proposals were concepts tied to NASA's Asteroid Grand Challenge, while the rest dealt directly with components of the asteroid-retrieval mission.
NASA's asteroid retrieval mission has sparked intense debate among members of Congress over whether the space agency should maintain its focus on manned asteroid exploration or shift instead to a moon-oriented goal.

Garver said today that asteroid exploration and lunar exploration should not be viewed as an either/or choice, but as complementary targets for future human and robotic spaceflight. But new lunar exploration missions should aim for a sustained presence on the moon, and not just be a repeat of NASA's Apollo lunar landings, she added.

"We truly have an increased focus on sustainable lunar activity," Garver said.
NASA's request for information on its asteroid plans is one of three calls for input by the agency on several space exploration efforts. On July 2, NASA launched a call for ideas from private space industry to learn more about how the agency might work with commercial moon lander missions. On July 17, NASA released a call for proposals from private spaceflight companies for unfunded partnerships with the space agency that could take advantage of the agency's expertise.

Source of Article: Space.com

2013년 7월 18일 목요일

Space Cloud Ripped Apart by Milky Way's Giant Black Hole

Astronomers have spied a huge gas cloud being pulled like taffy around the supermassive black hole at the heart of the Milky Way.
Their observations suggest that the space cloud will be completely ripped apart over the next year as it swirls closer to the galactic drain.
Most galaxies are thought to have enormous black holes at their center, and the one at the middle of the Milky Way — roughly 25,000 light years from Earth — has a mass about four million times that of the sun.

Scientists first spotted a gas cloud accelerating toward our galaxy's supermassive black hole in 2011. Data from 2004 show that the cloud was once shaped like a circular blob, but the intense gravitational forces of the black hole have now stretched it spaghetti-thin, researchers say.

Their new observations were made this past April with the European Southern Observatory's Very Large Telescope (VLT) in Chile. The cloud's light becomes more difficult to spot the more it gets stretched, but a 20-hour exposure with the VLT's special infrared spectrometer, called SINFONI, allowed scientists to measure the cosmic body getting closer to its doom.

Scientists still don't know where exactly the gas cloud came from, but they say the new observations rule out some possibilities.
"Like an unfortunate astronaut in a science fiction film, we see that the cloud is now being stretched so much that it resembles spaghetti," Stefan Gillessen, of the Max Planck Institute for Extraterrestrial Physics in Germany, who led the observing team, said in a statement. "This means that it probably doesn't have a star in it. At the moment we think that the gas probably came from the stars we see orbiting the black hole."
At its closest approach, the grossly stretched cloud is a little more than 15 billion miles (25 billion km) from the black hole itself — about five times Neptune's distance from the sun, the researchers say. This is dangerously close considering the black hole's humongous mass, and the cloud, Gillessen says, is "barely escaping falling right in."

Gillessen and colleagues say the head of the cloud has already whipped around the black hole and is speeding back in our direction at more than 6.2 million mph (10 million km/h), roughly one percent the speed of light. The tail is following at a slower pace (about 1.6 million mph, or 2.6 million km/h).
"The cloud is so stretched that the close approach is not a single event but rather a process that extends over a period of at least one year," Gillessen said in a statement.
The new observations will be detailed in the Astrophysical Journal. Scientists plan to intensely monitor the region throughout the year to watch as the cloud gets completely torn apart — a rare opportunity to test theories about how black holes pull in mass.

Source of Article: Space.com

Comet of the Century? Comet ISON Faces Risky Road

About 10,000 years ago, Comet ISON left our solar system's distant shell, a region known as the Oort cloud, and began streaking toward the sun. This November, the icy wanderer will reach the climax of its journey, potentially providing a stunning skywatching show here on Earth.

Comet ISON was discovered just last September by two Russian amateur astronomers. Scientists have since recognized ISON as a possible "comet of the century," but to live up to its promise, it will have to survive its dangerous perihelion, or closest approach to the sun. 
ISON is what's known as a sungrazing comet. These suicidal objects have orbits that bring them within 850,000 miles (1.4 million kilometers) of the sun, and scientists estimate that ISON's closest pass will be about 730,000 miles (1.2 million km) above the surface of Earth's star.

Sometime this month or perhaps in August, ISON is set to cross what's called the frost line. At this boundary, which lies some 230 million to 280 million miles (370 to 450 million km) from the sun, our star's radiation will start taking its toll on the comet, driving off more of its water and making ISON appear brighter.
ISON's road will only get rockier from there. After the comet flies by Mars in October and then Mercury in mid-November, intensifying solar radiation will boil more material off ISON; pressure from solar particles could break the comet into pieces; tidal forces will create great gravitational stress; and one ill-timed solar storm could rip the comet's tail right off.

All eyes will be on ISON as it makes this perilous journey. The comet has already had its picture taken by NASA's Hubble Space Telescope and Swift spacecraft, and in the coming months, the agency has a slew of ISON observations planned for its solar telescopes in space and some instruments on the ground.
In September, NASA will even launch a comet-watching balloon almost 23 miles (37 km) above Earth's surface to capture images of ISON with minimal interference from the atmosphere.
If the sun is merciful to ISON when it whips around the star on Nov. 28 (Thanksgiving Day), the comet could light up the sky for weeks. In the Northern Hemisphere, it could be visible in the morning near the east-southeast horizon in early December. Later in the month, and into early January, the comet could be visible all night, according to NASA.

Even if ISON fizzles, tracking the comet's path and reaction to solar forces could shed light on the makeup of the early solar system, scientists say.
Sungrazing comets like ISON sometimes plunge into parts of the sun's fiery atmosphere where no spacecraft can go. Researchers can learn about the sun itself by watching how the comet and its tail interact with the solar atmosphere.

For example, Comet Lovejoy passed just 87,000 miles (140,000 km) above the solar surface in mid-December 2011. The strange wiggle of Lovejoy's tail as it dove through the sun's corona helped scientists map out the region's complex magnetic field.

Source of Article: Space.com

Earth's Gold May Come From Collisions of Dead Stars

All of the gold on Earth might have come from cosmic crashes between superdense dead stars, new research suggests.

The origin of the universe's gold is mysterious, since it's not formed within stars like lighter elements such as carbon and iron. But the mystery may now be solved, as a new study posits that the collision of two neutron stars — the tiny, incredibly dense cores of exploded stars — could catalyze the creation of the valuable metal.
"We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 moon masses — quite a lot of bling!" lead author Edo Berger, of the Harvard-Smithsonian Center for Astrophysics (CfA), said in a statement. "To paraphrase Carl Sagan, we are all star stuff, and our jewelry is colliding-star stuff."

Berger and his colleagues studied a short gamma-ray burst — a class of explosions that are among the most luminous known in the universe — spotted by NASA's Earth-orbiting Swift spacecraft in early June. 

Called GRB 130603B, the gamma-ray burst was located about 3.9 billion light-years from Earth and lasted for less than two-tenths of a second. In the aftermath of the burst, scientists noticed that the explosion gave way to a gradually fading glow dominated by infrared light.
The research team thinks the burst's glow comes from "exotic radioactive elements," which can be spawned by the neutron-rich material thrown out into the universe by colliding neutron stars.

"We’ve been looking for a 'smoking gun' to link a short gamma-ray burst with a neutron star collision," co-author Wen-fai Fong, a CfA graduate student, said in a statement. "The radioactive glow from GRB 130603B may be that smoking gun."
Gold is rare on Earth because it's rare in the universe. In all, the team expects that the gamma-ray burst ejected about one one-hundredth of a solar mass of material, with some of it being gold.

"By combining the estimated gold produced by a single short GRB with the number of such explosions that have occurred over the age of the universe, all the gold in the cosmos might have come from gamma-ray bursts," CfA officials wrote in a press release today (July 17).
The new study has been submitted to the journal Astrophysical Journal Letters. Berger presented the results today during a press conference at the CfA in Cambridge, Mass.

Source of Article: Space.com

2013년 7월 12일 금요일

Kepler Spacecraft Should Pin Down 'Alien Earth' Planets Despite Glitch

NASA's planet-hunting Kepler spacecraft should be able to achieve its primary mission goal regardless of whether or not it can bounce back from a recent malfunction, researchers say.
Kepler launched in March 2009 on a 3.5-year prime mission to determine how common Earth-like planets are throughout the Milky Way galaxy. That goal is likely already attainable, even if the spacecraft is unable to recover from the glitch that halted its exoplanet hunt two months ago, mission team members say.
"We believe we do have enough data to answer the question," said Kepler analysis lead Jon Jenkins of the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, Calif.
"Now, we won't have as tight error bars as we would otherwise have, and we won't have orbital periods out well beyond Earth's in terms of Earth-size planets," Jenkins said during a lecture last month at the SETI Institute. "But we'll still do a credible job and a good enough job delivering the answers that we need."
Kepler spots exoplanets by noting the tiny brightness dips caused when they cross the face of their parent stars. The observatory needs to see three of these "transits" to flag an alien world, so it takes years to detect planets orbiting relatively far from their stars.
This is precision work, and the Kepler space telescope requires three functioning gyroscope-like reaction wheels to stay locked onto its 150,000-plus target stars.
The observatory launched in 2009 with four reaction wheels — three for immediate use, and one spare. One wheel, known as number two, failed in July 2012. Another (number four) stopped working on May 11 of this year, robbing Kepler of its precision pointing ability.
Kepler hasn't searched for exoplanets since the latter wheel failure. Mission engineers have been devising possible fixes for the problem, and they plan to start sending some of these commands to the spacecraft over the next week or two.
(Launching astronauts out to repair Kepler, as was done five separate times with NASA's Hubble Space Telescope, is not an option. Kepler orbits the sun rather than Earth and currently sits millions of miles from our planet.)
If at least one of the failed wheels cannot be brought back, Kepler will almost certainly be given a new mission, researchers say — one that emphasizes scanning instead of its previous point-and-stare operations.
While the Kepler team would love to continue the exoplanet hunt for years to come, researchers can likely determine the Milky Way's frequency of Earth-like worlds with the data the spacecraft has already collected, Jenkins said. But doing so will require a fair bit of work.
For one thing, he said, the team needs to continue pulling planets out of the spacecraft's huge dataset. (To date, Kepler has detected 3,277 candidate planets, 134 of which have been confirmed by follow-up observations. Mission scientists think at least 90 percent of the spacecraft's finds will end up being the real deal.)
Scientists also need to determine the completeness and reliability of Kepler's discovery system, among other things, and understand how the mission's target stars relate to the stellar population of the Milky Way as a whole to enable extrapolation, Jenkins added.
The target stars "were chosen to be really good for discovering transiting planets but undoubtedly have selection biases in them," he said.
All of this work should keep mission scientists busy for some time to come.
"We have about two years of data that we have yet to fully search; we're still in the process of searching through the third year of data," Jenkins said. "I think that this could occupy us for another two to three years, easily."
The Kepler mission's total pricetag is about $600 million thus far, and it costs about $20 million per year to operate the spacecraft and analyze the data, NASA officials have said.

Source of Article: Space.com

Comet Pan-STARRS Cuts Like a Knife In Amazing Photo

Comet Pan-STARRS slices through the night sky like a bright blade of light in this stunning image by an amateur astronomer.
Skywatcher Joseph Brimacombe captured this comet photo on May 23 from New Mexico using a FSQ 10.6-cm and STL11K camera at 10h 07m UT (mid-point). The image was taken in a single 30-minute exposure.
In this image, the comet Pan-STARRS' anti-tail can be seen stretching to the right. The anti-tail is one of the three tails that appears to come from a comet as it passes close to the sun. It's called the anti-tail because, when viewed from Earth, it appears to project from the comet's coma (or head) toward the sun. This makes it opposite to the other tails of the comet, the ion and dust tails.
Comet Pan-STARRS, named after a telescope in Hawaii, is thought to have an elliptical orbit around the sun that creates an 110,000-year path. The comet was discovered in June 2011 by astronomers using the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), a telescope that searches for near-Earth objects from a perch atop Haleakala volcano in Hawaii. The comet is officially known as comet C/2011 L4 Pan-STARRS.
On March 10, the comet made its closest approach to the sun, flying within 28 million miles (45 million kilometers) of the star before heading on its way back to the outer solar system.  
Comet Pan-STARRS is one of several comets in the night sky in 2013. Later this year, the much-anticipated Comet ISON will make its closest approach to the sun and could potentially become the "comet of the century" if it lives up to the expectations of some astronomers.
Comet ISON was discovered in September 2012 by amateur astronomers in Russia and will approach within a mere 800,000 miles (1.2 million km) of the sun on Nov. 28 during its pass through the inner solar system. If the comet survives the encounter, it could flare up into a brilliant night sky object, potentially shining as bright as the full moon seen in daylight conditions.
But the comet could also fizzle out, so astronomers are keeping close tabs on Comet ISON to track its progress.

Source of Article: Space.com

Strange Blue World: Alien Planet's True Color Revealed, a First

Call it the deep blue dot. For the first time, scientists have seen the visible color of a distant alien world. The exoplanet — called HD 189733b — is 63 light-years from Earth and a "deep cobalt blue," with raging storms of glass rain and super-fast winds, scientists say.
The alien planet's blue color was pinned down using observations from the Hubble Space Telescope. Although the planet might be the same color as Earth from space, scientists think that HD 189733b is a "hot Jupiter" — a gas giant planet that orbits very close to its star. It takes 2.2 Earth days for the planet to travel fully around its sun.
"This planet has been studied well in the past, both by ourselves and other teams," said Frédéric Pont of the University of Exeter, U.K., leader of the Hubble observing program in a statement. "But measuring its color is a real first — we can actually imagine what this planet would look like if we were able to look at it directly."
The exoplanet's weather is less than ideal. Its atmosphere is more than 1,832 degrees Fahrenheit (1,000 degrees Celsius) and the planet rains glass sideways in 4,350 mile per hour (7,000 km/h) winds, according to Hubble officials.
In 2007, NASA's Spitzer Space Telescope helped scientists map the weather conditions of the strange alien planet when the spacecraft produced one of the first temperature maps of an exoplanet. The data revealed that temperatures on the day and night sides of the world differ by about 500 degrees Fahrenheit (260 degrees Celsius), causing the strong winds to blow.
Scientists aren't sure what causes the blue planet's coloration, however.
"It's difficult to know exactly what causes the color of a planet's atmosphere, even for planets in the solar system," Pont said. "But these new observations add another piece to the puzzle over the nature and atmosphere of HD 189733b. We are slowly painting a more complete picture of this exotic planet."
The research team uncovered the planet's color by measuring the light reflected off the surface of the planet.
"We saw the brightness of the whole system drop in the blue part of the spectrum when the planet passed behind its star," Tom Evans of the University of Oxford, U.K., the leader of the study being published in the Aug. 1 issue of the journal Astrophysical Journal Letters said in a statement. "From this, we can gather that the planet is blue, because the signal remained constant at the other colors we measured."

Source of Article: Space.com

2013년 7월 9일 화요일

Solar Flares Fire Off Antimatter Particles

Astronomers have detected exotic antimatter particles flying from the sun during solar flares — a discovery that could help scientists understand this mysterious sibling to matter.
Solar flares were predicted to release some antimatter particles among the deluge of charged particles spat out during these eruptions. But this is the first time researchers have observed antimatter coming from the sun.
Antimatter particles have the same mass and other characteristics as their regular-matter counterparts, but they have opposite charge. When the universe was born about 13.8 billion years ago in the Big Bang, there was probably about as much matter as antimatter, scientists think. Somehow, collisions with matter destroyed most of the antimatter (when matter and antimatter meet, they annihilate), leaving a slight surplus of matter, which became the planets, stars and galaxies in our universe.
Studying natural sources of antimatter in the universe today may help researchers understand why antimatter lost that battle to matter all those eons ago.
"That such particles are created in solar flares is not a surprise, but this is the first time their immediate effects have been detected," scientists wrote in a statement from the New Jersey Institute of Technology, the home institution of study leader Gregory D. Fleishman, who will present the findings this week at the 44th meeting of the Solar Physics Division of the American Astronomical Society in Bozeman, Mont.
The study detected antimatter particles called positrons — the antimatter partners to the mundane electrons that populate normal atoms. Powerful processes on the surface of the sun had ejected the particles, speeding them up to near light speed. Interactions of atomic nuclei, which the solar flare had accelerated, likely created the positrons.
Solar flares erupt on the sun when pent up magnetic energy is released, causing the sun to brighten and pour out powerful radiation.
To detect the positrons, Fleishman and his colleagues used NASA's Solar and Heliospheric Observatory (SOHO) and observations from Japan's Nobeyama Radioheliograph to study the polarization, or orientation, of radio light emitted by solar flares.
The researchers found that the light was polarized in different directions at lower frequencies, where normal matter dominates, compared to higher frequencies, where more antimatter is expected. This effect is just what the scientists expected based on the opposite charges of matter and antimatter.

Source of Article: Space.com

Incredible Technology: How to See a Black Hole

Black holes are essentially invisible, but astronomers are developing technology to image the immediate surroundings of these enigmas like never before. Within a few years, experts say, scientists may have the first-ever picture of the environment around a black hole, and could even spot the theorized "shadow" of a black hole itself.
Black holes are hard to see in detail because the large ones are all far away. The closest supermassive black hole is the one thought to inhabit the center of the Milky Way, called Sagittarius A* (pronounced "Sagittarius A-star"), which lies about 26,000 light-years away. This is the first target for an ambitious international project to image a black hole in greater detail than ever before, called the Event Horizon Telescope (EHT).
The EHT will combine observations from telescopes all over the world, including facilities in the United States, Mexico, Chile, France, Greenland and the South Pole, into one virtual image with a resolution equal to what would be achieved by a single telescope the size of the distance between the separated facilities.\
"This is really an unprecedented, unique experiment," said EHT team member Jason Dexter, an astrophysical theorist at the University of California, Berkeley. "It's going to give us more direct information than we've ever had to understand what happens extremely close to black holes. It's very exciting, and this project is really going to come of age and start delivering amazing results in the next few years."
From Earth, Sagittarius A* looks about as big as a grapefruit would on the moon. When the Event Horizon Telescope is fully realized, it should be able to resolve details about the size of a golf ball on the moon. That's close enough to see the light emitted by gas as it spirals in toward its doom inside the black hole.
Very long baseline interferometry
To accomplish such fine resolution, the project takes advantage of a technique called very long baseline interferometry (VLBI). In VLBI, a supercomputer acts as a giant telescope lens, in effect.
"If you have telescopes around the world you can make a virtual Earth-sized telescope," said Shep Doeleman, an astronomer at MIT's Haystack Observatory in Massachusetts who's leading the Event Horizon Telescope project. "In a typical telescope, light bounces off a precisely curved surface and all the light gets focused into a focal plane. The way VLBI works is, we have to freeze the light, capture it, record it perfectly faithfully on the recording system, then shift the data back to a central supercomputer, which compares the light from California and Hawaii and the other locations, and synthesizes it. The lens becomes a supercomputer here at MIT."
A major improvement to the Event Horizon Telescope's imaging ability will come when the 64 radio dishes of the ALMA (Atacama Large Millimeter/submillimeter Array) observatory in Chile join the project in the next few years.
 "It's going to increase the sensitivity of the Event Horizon Telescope by a factor of 10," Doeleman said. "Whenever you change something by an order of magnitude, wonderful things happen."
Very long baseline interferometry has been used for about 50 years, but never before at such a high frequency, or short wavelength, of light. This short-wavelength light is what's needed to achieve the angular resolution required to measure and image black holes.

Grand technical challenge
Pulling off the Event Horizon Telescope has been a grand technical challenge on many fronts.
To coordinate the observations of so many telescopes spread out around the world, scientists have needed to harness specialized computing algorithms, not to mention powerful supercomputers. Plus, to accommodate the time difference between the various stations, extremely accurate clocks are needed.
"We had to prove you could keep time well enough at all the stations, and that the detectors at all the telescopes were good enough, that when you multiply the two signals from two telescopes you wouldn’t get just noise," said Dan Marrone, an astronomer at the University of Arizona's Steward Observatory who's building a receiver to enable the South Pole Telescope to join the project. 
The researchers have been using atomic clocks made of what's called hydrogen masers to keep time to an accuracy of about a trillionth of a second per second.
"We use this property of the structure of the hydrogen atom to create a fundamental time reference for us that transitions between two states of the electron in a hydrogen atom," Marrone said. "It creates a low-frequency signal that through careful design you can make a very precise oscillator. It creates very perfect oscillations for a short time period. That means we can average our data over those time periods because they will all have kept time very perfectly." 
Testing general relativity
With the unprecedented data soon to be collected by the Event Horizon Telescope, scientists are hoping to better understand the strange physics of black holes, which are some of the most extreme, bizarre objects in the universe.
The black hole at the center of the Milky Way is thought to contain the mass of about 4 million suns, all packed into an incomprehensibly small area. The ultra-strong densities there should produce some very extreme gravitational forces that offer a rare test of Einstein's general theory of relativity.
"The Event Horizon Telescope is going to look at emission at the edge of the black hole itself," Doeleman said. "That's an area where the gravity is so strong that light is bent and the structures you see are dominated by strong gravity, where you absolutely need Einstein to understand what you're seeing. It becomes a laboratory of extremes."
One question scientists hope to answer is whether black holes really have event horizons, as predicted by general relativity. An event horizon is a theorized boundary around a black hole that marks the "point of no return" where matter and even light can't escape. If event horizons exist, general relativity also predicts black holes will have shadows, or darkened regions where light has been swallowed. If black holes do produce shadows, the Event Horizon Telescope should be able to see one at Sagittarius A* within the next few years, said Dexter, the University of California, Berkeley, theorist.
"That would be the most extreme general relativistic effect detected so far," he added.
X-raying black holes
While the Event Horizon Telescope is observing black holes in radio wavelengths, the other frontier of black hole astronomy is in the X-ray regime.
The gas falling into black holes emits light across the electromagnetic spectrum, but the hottest, most energetic gas, which is swirling closest to a black hole's event horizon, can be seen in X-ray light.
This light is only visible beyond the atmosphere of Earth, to space telescopes such as NASA's Chandra observatory and NuSTAR telescope, Europe's XMM Newton observatory, and Japan's Suzaku telescope. These observations aren't directly imaging the environs of black holes, like the Event Horizon Telescope, but are breaking up X-ray light into its constituent colors, or wavelengths, to search for clues about what's happening to the gas in those extreme environments.
For example, astronomer Chris Reynolds of the University of Maryland, College Park, uses X-ray observations to study the spins of black holes. "Because the physics is so extreme, when a black hole spins, it actually twists up the space-time around it and we can see the effect it has on gas orbiting the black hole," Reynolds said.
And by studying black holes in various wavelengths, researchers hope to build up a more complete understanding of these strange cosmic objects.
"The gas, as it falls into a black hole, emits radio waves, which is what the Event Horizon Telescope is trying to see, and it also makes X-rays, and that gives you very complementary views on the properties of the infalling gas and the black hole," Reynolds said. "The Event Horizon Telescope is on the threshold of some extremely close results, and we're all looking forward to it."

Source of Article: Space.com

2013년 7월 7일 일요일

Mars Rover Opportunity Hits Driving Milestone on 10th Birthday

On the 10th anniversary of its launch, NASA's Opportunity rover on Mars is also celebrating reaching the halfway point in its drive from one crater-rim segment to another.
The Opportunity rover, which is still going strong on the Red Planet long after its official mission was slated to end, is journeying 1.2 miles (2 kilometers) from the spot it studied for the past 22 months, on the edge of Mars' Endeavour crater, to another area where it will begin a new phase in its research.
Sunday (July 7) marks the 10th anniversary of Opportunity's launch from Earth with its sister rover Spirit, which shut down on Mars in 2010. The rovers lifted off in 2003, and arrived at the Red Planet in January 2004. They were originally expected to operate for three months.
With its mission clock at nine years and counting, Opportunity is still uncovering secrets on Mars. The robot was last based at thesouthern tip of the "Cape York" segment of the 14-mile-wide (22 kilometers) Endeavour crater, and is now on its way to a spot called "Solander Point." It began the trip in mid-May, and has been driving for about six weeks.
To get from one area to the other, Opportunity has to cross a region called "Botany Bay."
 "The surface that Opportunity is driving across in Botany Bay is polygonally fractured outcrop that is remarkably good for driving," Brad Joliff, an Opportunity science team member and long-term planner at Washington University in St. Louis, said in a statement. "The plates of outcrop, like a tiled mosaic pavement, have a thin covering of soil, not enough to form the wind-blown ripples we've had to deal with during some other long treks. The outcrop plates are light-toned, and the cracks between them are filled with dark, basaltic soil and our old friends the 'blueberries.'"
Blueberries are small, spherical hematite-rich formations that Opportunity first discovered when it landed at another crater, called Eagle.
Opportunity has now traveled more than 22 miles (35 kilometers) on Mars, and recently broke the U.S. off-Earth driving record, which had previously been set by the Apollo 17 moon rover, driven by astronauts Gene Cernan and Harrison Schmitt over 22.21 miles (35.74 km) of the lunar surface in December 1972.
If Opportunity keeps chugging along on Mars, it may eventually break the worldwide extraterrestrial driving record, which was set in 1973 by the Soviet robotic moon rover Lunokhod 2, which traveled roughly 26 miles (42 km) over the moon.
And Opportunity isn't the only NASA spacecraft roving on Mars. The Mars Science Exploration Laboratory rover Curiosity arrived on the Red Planet in August 2012, and is exploring the Gale crater area.

Source of Article: Space.com

Weird Quantum Tunneling Enables 'Impossible' Space Chemistry

A weird quirk of quantum mechanics is allowing a chemical reaction thought to be impossible to occur in cold gas in outer space.
In the harsh environment of space, where the temperature is about minus 350 degrees Fahrenheit (minus 210 degrees Celsius), scientists had thought a certain reaction involving alcohol molecules couldn't take place, because at such low temperatures, there shouldn't be enough energy to rearrange chemical bonds. But surprisingly, research has shown that the reaction occurs at a rate 50 times greater in space than at room temperature.
Now, by simulating the conditions of space in a laboratory, scientists have found a possible explanation for how the reaction occurs: quantum tunneling.
Tunneling depends on the odd rules of quantum mechanics, which state that particles don't usually have decided states, positions and speeds, but exist in hazes of probability. This means that a particle might have a strong probability of being located on one side of a wall, but still retain a very small chance of actually being on the other side of it, allowing it, occasionally, to "tunnel" through a wall that would otherwise be an impassable barrier.
This tunneling ability might allow particles to undergo chemical reactions that should be impossible due to the lack of energy at the low temperatures of space.
"The answer lies in quantum mechanics," chemist Dwayne Heard of the University of Leeds in the U.K., who led the research, said in a statement. "Chemical reactions get slower as temperatures decrease, as there is less energy to get over the 'reaction barrier.' But quantum mechanics tells us that it is possible to cheat and dig through this barrier instead of going over it. This is called 'quantum tunneling.'"
Quantum tunneling states last only very, very briefly, making reactions taking advantage of them difficult. But that's where the cold temperature might help, because some molecules formed during the reaction process might be transient at room temperature, but last slightly longer at very cold temperatures.
"We suggest that an 'intermediary product' forms in the first stage of the reaction, which can only survive long enough for quantum tunneling to occur at extremely cold temperatures," Heard said. 
In a lab, Heard and his colleagues created the same cold conditions in space, and observed reactions of the alcohol methanol with an oxidizing chemical called a hydroxyl radical, and found that these gases react to create methoxy radicals.
Now, the scientists want to test other types of alcohol-related reactions under similar conditions.
"If our results continue to show a similar increase in the reaction rate at very cold temperatures, then scientists have been severely underestimating the rates of formation and destruction of complex molecules, such as alcohols, in space," Heard said. 

Source of Article: Space.com

Mysterious Deep-Space Explosions Baffle Scientists

Powerful and puzzling radio blasts in other galaxies constantly explode across the night sky, a new study suggests.
A team of international astronomers has detected four explosive events, known as fast radio bursts (FRBs), above the plane of our Milky Way Galaxy. Lasting only a few thousandths of a second, these sources send powerful signals across the universe, traveling billions of light-years through space.
"These bursts gave off more energy in a millisecond than the sun does in 300,000 years," said principal investigator Dan Thornton of the University of Manchester in England.
Mysterious origins
Studying observations by the CSIRO Parkes radio telescope in Australia, Thornton and his team spotted four new point sources across the sky. The bursts ranged from 5.5 to 10 billion light-years away, meaning it took the light from some of them 10 billion years to reach Earth. (The Big Bang that created our universe occurred 13.8 billion years ago.).
These newfound objects allowed the researchers to calculate that an FRB should occur once every 10 seconds.
After the astronomers verified that the objects weren't Earth-based, they questioned whether the new signals came from inside or outside the Milky Way. To do so, they studied how the radio waves were affected by the material they pass through — a technique that could allow these new objects to shed light on the components of space.

As radio waves travel in space, they are stretched and slowed by the ionized material through which they move. Using models, the team concluded that the FRBs traveled billions of light-years — much farther than the edge of Earth's galaxy.
"These are extragalactic in origin — not from the Milky Way — but the source is likely located in another galaxy," Thornton said.
Although the explosions are brief, the astronomers can pinpoint the bursts' locations pretty accurately.
"They are so bright and narrow that we can limit the size of the emission region at the source to just a few hundred kilometers," Thornton said.
No corresponding object could be observed in optical, gamma or X-ray wavelengths, so the explosions' origins remain unknown to scientists.
"Other variable extragalactic radio sources vary on timescales of days to months," Thornton said. "FRBs happen in just a few milliseconds."
Possible sources include intersecting magnetic fields from two neutron stars, extremely dense city-size bodies packing the mass of the sun. A special kind of supernova orbited by a neutron star could potentially produce radio bursts as the star's magnetic field interacts with the explosion of the supernova, though such combinations would be rare, researchers said.
"Our favorite explanation is a giant burst from a magnetar, a highly magnetized type of neutron star," Thornton said.
These bursts of radiation can produce an enormous amount of energy, similar to that seen in the FRBs.
Hard to spot
Although frequent, an FRB's short signal duration makes it difficult to spot.
"The problem with searching for FRBs is that we don't know where or when they will go off," Thornton said.
A single fast radio burst was detected in 2007, leaving scientists puzzled about its source, and even its existence. For the last four years, Thornton and his team have used the High Time Resolution Survey to search for similar bursts. Powered by the 210-foot (64 meters) CSIRO Parkes radio telescope, the survey was designed to search above and below the plane of the Milky Way for objects such as rotating neutron stars known as pulsars.
The Parkes telescope essentially "stares" at a region of the sky for a set amount of time, making it ideal to capture FRBs.
"At some point, one will go off in the field of view of the telescope," Thornton said.
The four new sources appeared above the plane of the galaxy. Follow-up observations, performed approximately a year after the FRBs were first spotted, looked at whether the objects continued to produce emission, but the signals appear to be nonrepeating.
"It is, of course, possible that repetitions were missed, particularly if they happened soon after the original FRB," Thornton said.
"Efforts are ongoing at the moment to detect FRBs in close to real time, such that they can be followed up quickly," he added. Ideally, such follow-up observations would be performed at a multitude of wavelengths, providing further insight into what drives these powerful explosions.

Source of Article: Space.com