Incoming Comet ISON Now Visible in Binoculars

The potentially dazzling Comet ISON has brightened enough on its highly anticipated approach toward the sun that it's now visible through a decent pair of binoculars.

Skywatchers around the world have recently used binoculars to spot Comet ISON, which is streaking toward a close encounter with the sun on Nov. 28 that will bring the icy wanderer within just 730,000 miles (1.2 million kilometers) of the solar surface.

"I have made my first confirmed binocular sighting of C/2012 S1 ISON as well," Pete Lawrence, of the town of Selsey in the United Kingdown, told the website Spaceweather.com on Saturday (Nov. 9). "ISON's head appears small and stellar through a pair of 15x70s optics." 

Comet ISON is cruising through the constellation Virgo at the moment and is visible in binoculars low in the predawn eastern sky, Spaceweather.com reports. The comet is currently as bright as an 8th magnitude star — too dim to be seen with the naked eye but easy to spot with binoculars or a small telescope.

ISON was discovered by two Russian amateur astronomers in September 2012, giving scientists more than a year to prepare for its close solar flyby. Researchers have been tracking the comet with a variety of instruments on the ground and in space, hoping to learn about ISON's composition by watching which gases boil off its surface at various distances from the sun.

Skywatchers have had a keen interest in ISON as well, for the comet could put on a great show in December if it survives its close pass by the sun later this month.

While some researchers have voiced optimism that ISON will hold together, there are certainly no guarantees; it's tough to predict the behavior of any comet, particular a "dynamically new" one such as ISON that's making its first trip to the inner solar system from the distant and frigid Oort Cloud.

Source of Article: Space.com

Curiosity Rover Suffers Software Glitch On Mars

NASA's Mars rover Curiosity rebooted its software after an unexpected glitch late last week, but the six-wheeled robot is now doing fine on the surface of the Red Planet, NASA officials say.

The reboot — also known as a "warm reset" — occurred on Thursday (Nov. 7), less than five hours after Curiosity's handlers had uploaded new flight software to the 1-ton rover. It was the first time Curiosity had experienced such a fault-related reboot since landing on Mars in August 2012, officials said.

"Telemetry later downlinked from the rover indicates the warm reset was performed as would be expected in response to an unanticipated event," Curiosity project manager Jim Erickson, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

Warm resets are triggered when a spacecraft's flight software identifies a problem with one of its operations. While mission team members are still working to figure out what exactly happened, the glitch does not appear to pose any serious problems.

"So, that happened. Had a warm reset yestersol. I'm healthy. Spending the weekend awaiting new instructions," NASA officials said Friday (Nov. 8) via Curiosity's official Twitter feed, @MarsCuriosity. (A "sol" is one Martian day, which is about 40 minutes longer than a day here on Earth.)

The 1-ton Curiosity rover touched down inside Mars' huge Gale Crater on Aug. 5, 2012, kicking off a planned two-year surface mission to determine if the Red Planet has ever been capable of supporting microbial life. The robot has already achieved that goal, finding that an area near its landing site called Yellowknife Bay was indeed habitable billions of years ago.

Curiosity is now on its way to the towering Mount Sharp, which rises 3.4 miles (5.5 km) into the Martian sky from Gale Crater's center. Mission scientists want the rover to climb up through Mount Sharp's foothills, reading the history of Mars' changing environmental conditions as it goes.

The trek from Yellowknife Bay to the base of Mount Sharp covers about 5.3 miles (8.6 km). Curiosity embarked upon this journey in early July and is about one-third of the way to the mountain, which has been its primary destination since before the rover's November 2011 launch.

Source of Article: Space.com

Moon Surprise: Lunar Craters Are Bigger on Near Side

The near side of the moon hosts larger impact basins than the satellite's far side, and the explanation lies in key differences between the two hemispheres, a new study suggests.

Scientists have long understood that craters form at an even rate on the surfaces of both sides of the moon, but new work reports that ancient asteroid impacts on the near side of the moon produced larger basins than those on the far side.

The surprising difference hinges upon the composition of the crust on the two sides of the moon. The near side, which always faces Earth, was warm during the early formation of the moon and subjected to volcanic activity. This might have created an ideal environment for big craters to form, scientists said.

"When we look at the maps of both hemispheres, we realize there are more big basins on the near side than on the far side," said Katarina Miljkovic of the Institute de Physique du Globe de Paris, lead author of the new moon study published in the Nov. 8 issue of the journal Science. "There are eight of them on the near side that are bigger than 300 kilometers [186 miles]… and only one on the far side."

Using data  gathered by NASA's Gravity Recovery and Interior Laboratory(GRAIL) spacecraft, Miljkovic and her colleagues ran computer simulations to model the effects of long-ago impacts on the moon's crust. They found that an impact on the near, hotter side of the moon would form a crater about two times larger than craters formed by a similarly sized asteroid on the cold, far side of the moon.

The near side's hot crust didn't fall back into itself when struck like the cold, stiff crust of the far side. Instead, the malleable surface of the near side was able to expand, creating larger basins and displacing more of the crust, even if the impactor was not necessarily huge, Miljkovic found.

The new work could have implications for scientists' understanding of the solar system's early days, researchers said.

Scientists have long thought that huge numbers of comets and asteroids impacted Earth, the moon and other bodies in the inner solar system from about 3.8 billion to 4.1 billion years ago. In light of this new work, however, ideas about that period, known as the "late heavy bombardment," might need to be altered, Miljkovic said.

The mass of space rocks hurling toward Earth and the moon during the late heavy bombardment period may be overestimated, Miljkovic said.

"These big basins on the near side appear larger than they should," Miljkovic told SPACE.com. "If we only rely on the near side basins to give us information about the late heavy bombardment for impact flux, then it is possible that it is likely overestimated."

Much of the information scientists have gleaned about the late heavy bombardment comes from moon craters, so if the large basins formed differently than originally thought, it might necessitate a change in the way researchers understand the history of the solar system, said Noah Petro, a research scientist working with NASA's Lunar Reconnaissance Orbiter mission.

"All of the understanding of impacts goes back to the moon," Petro, who is unaffiliated with the new study, told SPACE.com. "Until we really understand what happened on the moon, it's difficult to apply it to other bodies. There have been lines of evidence drawn from other bodies, but ultimately it cycles back to our understanding of what happened on the moon."

Source of Article: Space.com

Recognizing Giant Leaps: Google Lunar XPRIZE Establishes Milestone Prizes (Op-Ed)

Back in 2007, building upon the successes of the Ansari XPRIZE for suborbital spaceflight and the Northrop Grumman Lunar Lander Challenge, XPRIZE and Google launched the $30 million Google Lunar XPRIZE, the largest incentivized competition to date. The concept was easy to explain: land on the moon, move 500 meters and send back video, images and data. The prize requirements were conceived to demonstrate the minimum useful capability a spacecraft would need for future uses in space exploration and scientific research.

Thirty teams signed up for this audacious challenge by the close of registration in 2010 — three times as many as the initial concept study had suggested. Going back to the moon had clearly struck a chord!

This week, XPRIZE and Google announced a series of Milestone Prizes available to competing teams. The reason for introducing these prizes deserves a little background.

Over the past decade, XPRIZE has successfully launched and awarded a number of competitions, learning a great deal about what makes for optimum prize design. We've learned that success is more likely if we continue to keep our eye on the entire ecosystem surrounding a prize, and when we address any significant challenges to that ecosystem that may arise.

Given the large investment investment needed to send a robot to the moon, two elements of the Google Lunar XPRIZE ecosystem are critical: potential customers for the technology developed by teams, and investors to help create the businesses to leverage those markets. In both of these areas, much has changed since the Google Lunar XPRIZE was launched. The global economic downturn has reduced an already small pool of investors who are willing to take risks on pioneering new markets. This same downturn has also stagnated or reduced the budgets that governments — usually an early future customer — are willing to spend in space exploration (of note, NASA has changed its focus from going back to the moon to exploring asteroids ).

Two years ago, XPRIZE began a dialogue with teams to better understand the challenges that they were facing and to determine what steps we might take to better nurture and support this prize ecosystem. As a result, we determined that we needed to find a way to recognize and support the teams that were making substantial technical progress toward the requirements of the competition.

Hence the newly announced Milestone Prizes.

Within the next year, there are certain developmental milestones for flight-ready hardware that teams must pass in order to meet the mission requirements and be ready to launch by the deadline of Dec. 31, 2015.

Recognizing and rewarding these milestones will not only help the competing teams by allowing them to access financing at a critical point in their mission timeline, but it will also raise public excitement and support for the teams.

The Milestone Prizes are for demonstrating (via actual testing and analysis) robust hardware and software to combat key technical risks in the areas of imaging, mobility and lander systems — all three being necessary to achieve a successful Google Lunar XPRIZE mission. Teams will submit their proposals to our judging panel, which will select up to four proposals to monitor in each of the imaging and mobility subsystems, and three proposals for the lander system, for a total of 11 proposals. A team may have proposals selected in more than one area.

Provided the team successfully accomplishes the tasks described in their selected proposal in the timeframe agreed, they will win a Milestone Prize. The amounts are $250,000 for the Imaging Subsystem Milestone Prize (for up to 4 teams), $500,000 for the Mobility Subsystem Milestone Prize (for up to 4 teams), and $1 million for the Lander System Milestone Prize (for up to 3 teams), for a total purse of $6 million. The Milestone Prizes can be won through the end of September 2014.

With the introduction of these prizes, 2014 is looking to be a very exciting year for the Google Lunar XPRIZE with critical hardware and software testing and many great opportunities to recognize our teams and their significant achievements. While we cannot fix the global economic downturn, we can at least highlight the ways in which our teams are bringing us closer to a new era of private lunar exploration, taking us back to the moon, for good.

Source of Article: Space.com

Bizarre Asteroid with Six Tails Spotted by Hubble Telescope (Photos)

Astronomers have spotted a never-before-seen phenomenon in our solar system's asteroid belt: a space rock with six tails, spewing dust from its nucleus like spouts of water radiating from a lawn sprinkler.

Scientists using the Pan-STARRS 1 telescope at the summit of Maui's Haleakala volcano in Hawaii first detected the six-tailed asteroid in August. They dubbed it P/2013 P5 and noted that it looked fuzzier than typical asteroids, which usually appear as tiny points of light. More detailed observations with the powerful Hubble Space Telescope in September revealed a clearer picture of asteroid, showing it had six comet-like tails.

"We were literally dumbfounded when we saw it," researcher David Jewitt of the University of California at Los Angeles said in a statement from NASA. "Even more amazing, its tail structures change dramatically in just 13 days as it belches out dust. That also caught us by surprise. It's hard to believe we're looking at an asteroid."

In the time between Hubble's first observation on Sept. 10 and its second peek at the asteroid on Sept. 23, the tails appeared to have completely swung around. Jewitt said he and his colleagues were "completely knocked out" by this finding.

The tails seem to have formed in bursts and not all at once, which is why the researchers don't think they formed as the result of an impact with another asteroid.

Rather, P/2013 P5 could have sprouted dust tails after it started spinning out of control. The researchers suspect radiation pressure caused the asteroid to start rotating faster and faster until its weak gravity no longer could hold it together, sending the surface material of the space rock flying off at several points in the asteroid's recent history.

The researchers even pinpointed when they think these recent dust-ejection events may have occurred, in a series of spurts from April to September.

Though seeing a six-tailed space rock is a first for astronomers, the new research hints that there could be more asteroids with debris trails emanating from their center.

"In astronomy, where you find one, you eventually find a whole bunch more," Jewitt said in a statement. "This is just an amazing object to us, and almost certainly the first of many more to come."

P/2013 P5 has only lost a fraction of its mass, about 100 to 1,000 tons of dust, which represents a tiny portion of the 1,400-foot-wide (425 meters) asteroid, the scientists said.

While P/2013 P5 likely isn't a victim of a recent collision, researchers think the asteroid may be one of the leftover fragments of a much larger space rock that broke apart 200 million years ago. And the space rock likely doesn't contain any water, the scientists believe, based on previous examinations of collision fragments that were in orbits similar but have to P/2013 P5 have made it down to Earth's surface in the form of meteorites.

Source of Article: Space.com

Promising Comet ISON Gives Perplexing Performance En Route to Sun

With just one month to go before its dramatic solar rendezvous, skirting to within a hairbreadth of the surface of the sun, Comet ISON continues to befuddle observers with its performance en route to the sun.

Based on a compilation of Comet ISON observations from observers worldwide as of Oct. 24, the comet, once proclaimed as possibly the "Comet of the Century" was running approximately 1.3 magnitudes, or 3.3 times fainter, than the "official" brightness forecast issued by the Minor Planet Center in Cambridge, Mass. As the comet comes down the home stretch of its long journeybefore finally grazing to within 730,000 miles (1.2 million kilometers) of the sun, great uncertainty continues regarding whether or not it will remain disappointingly dim or whether it will end up evolving into a spectacularly bright object.        

Carl Hergenrother of the Lunar and Planetary Laboratory in Tucson, Ariz., noted that part of the uncertainty is due to what wavelengths the comet is observed in: "Visual and CCD-V observations do show a comet that is brightening at a normal rate (perhaps even faster than normal for a dynamically new comet) while CCD-R observations show a comet that is barely brightening at all. CCD-R sees predominately dust in contrast with visual and CCD-V, which have large gas components. It seems that over the past month or so ISON's gas production rate has increased as expected while its dust production rate has not," Hergenrother said. "I don't really know what this means but something has to give, either the dust production picks up or the gas production slows down." 

Looking weird

The highly regarded comet observer John Bortle is just as perplexed by the comet's recent appearance, commenting that the recent images along with his own visual impression, is "downright weird." He adds that, "There is a bright, miniature, long-tailed comet situated within a much larger, but very much fainter and diffuse halo of a coma."

"

Those visual people using larger telescope also often remark about the odd way the comet looks, while those using relatively small scopes and big binoculars report seeing a larger, more-or-less faint but uniform cometary mass," he added. "This comet is currently at a distance from the sun where it should no longer exhibit such a dichotomy of appearance.” 

Bortle has observed several hundred comets and yet, he writes, "At this stage of the game, with the comet about to cross the orbit of Earth, I cannot recall any previous comet in my 50-plus years of comet observing looking quite like this. So, what does ISON's current look foretell, or mean? I honestly don't know. All I can say is I don't like the odd look of it at this time."

One step forward, one step back

Around Oct. 19, ISON seemed to suddenly brighten at a more rapid pace. On Oct. 21, Arizona observer Bruce Gary (who was the first to image the comet after it emerged from out of the glare of the sun on Aug. 12) wrote, "The comet (coma plus tail) continues a dramatic brightening trend that started Oct 19. The inner coma has brightened (due perhaps to an outburst of gases). This next week could be busy - and exciting!"

But just four days later, with the comet showing signs of fading a bit rather than brightening, Gary, sounding almost a bit exasperated commented, "I don't know what's going on with this comet!"

Analyzing all the observations made since Sept. 4 shows that ISON is responding to the sun more like a solid body would respond, rather than as a typical "fluffy" comet. 

Time Running Out

Whatever is happening, Comet ISON continues on its way in toward the sun and will cross the Earth's orbit on Wednesday (Oct. 30) at 6 p.m. EDT (22:00 GMT). 

For the last couple of months, observers watching the comet brighten at what has seemed to be a frustratingly slow pace are still waiting for a more rapid brightening trend. That may still happen, but time is now running out; four weeks from Thursday will be the comet's moment of truth as it whips around the sun.

Will it remain disappointingly dim? Will it finally brighten up? Will it still be completely intact when it sweeps back out into space or will the sun's extreme heat and tremendous tidal forces cause it to fracture into several pieces? At SPACE.com we will continue to monitor the comet's future behavior and provide any new updates in the days to come, so stay tuned!

Source of Article: Space.com

Russian Fireball Explosion Shows Meteor Risk Greater Than Thought

As researchers recover more leftover pieces from the space rock that detonated earlier this year near the Russian city of Chelyabinsk, the event is helping to flag a worrisome finding: Scientists have misjudged the frequency of large airbursts.

Computer simulations also imply that such airbursts cause more damage than nuclear explosions of the same yield, which are typically used as an analogue to ballpark impact risk.

The meteor explosion over Chelyabinsk gives the bottom-line message that the risk from airbursts is greater than previously thought.

Meteor explosion data points

Mark Boslough, a physicist at Sandia National Laboratories in New Mexico, broached the implications of the Chelyabinsk airburst event on Oct. 7 here at the American Astronomical Society's 2013 Division for Planetary Sciences meeting.

According to Boslough, when you add the Chelyabinsk incident to the 1908 Tunguska explosion over Siberia — along with a 1963 bolide blast near the Prince Edward Islands off the coast of South Africa — the data suggest that the incoming rate of small space rocks is actually much higher than asteroid experts have assumed based on astronomical observations. 

That Prince Edward Islands event was a 1.1-megaton explosion picked up by a global network of infrasound sensors, but not apparently seen by any observers.

"These three data points together suggest that maybe we have underestimated the population," of smaller sized objects that can create air bursts, Boslough said. "We think the airburst hazard is greater than previously thought."

Chelyabinsk consortium

The Feb. 15, 2013, explosion of a previously undetected asteroid about 25 miles (40 kilometers) from the Russian city of Chelyabinsk led to many injuries and widespread blast damage. But it has also spurred a wealth of data helping scientists to gauge the object's size, angle of entry and other specifics, Boslough said.

A "Chelyabinsk consortium" has been hard at work to better discern the varied characteristics of the fireball and the subsequent damage, he said.

The best estimate places the explosive yield of the space rock at 400 to 500 kilotons, Boslough said, making Chelyabinsk the most powerful such event observed since Tunguska, which is pegged at 3 to 5 megatons. (There are 1,000 kilotons in a megaton.)

The Chelyabinsk space intruder came in mostly from the east at 9:20 a.m. local time in Russia, bursting apart close to 19 miles (30 km) above the ground.

Pre-entry, the object had a diameter of roughly 65 feet (20 meters), with a mass of approximately 12,000 tons, Boslough said. It came in at an 18-degree angle, "a glancing blow," spreading its energy sideways and at an angle, which generated less damage on the ground, he said. Still, the outburst broke windows over several thousand square kilometers.

Out of the sun

Thanks to the work of colleague Peter Brown, a physics professor at the University of Western Ontario in Canada, Boslough said over 500 videos of the Chelyabinsk fireball have been collected, some of those no longer available via the Internet.

Boslough traveled to Chelyabinsk, where he performed calibrations of dashcam videos to help pinpoint the altitude and coordinates of the explosion.

"It came pretty much straight out of the sun," Boslough said.

Roughly 1,500 people were injured, "almost all by flying glass," due to a powerful, post-explosion shockwave, he said.

Duck and cover

On one hand, Boslough said that the old Cold War practice of "duck and cover" during a nuclear bomb drill is a bit quaint, "but it turns out that it would be the right thing to do" for the Chelyabinsk meteor.

"If you're not at ground zero, the way to keep yourself from getting hurt from a large explosion in the atmosphere is to stay away from windows," Boslough said.

But even armed with that fact, he admitted that scientific curiosity would assuredly have driven him for a look-see out the window.

"I probably know as much about airburst as anybody," Boslough said, "and I'd probably have my face pressed against the window, and as soon as the blast died down, I would have gone 'Oh, yeah.'"

Still, if scientists had discovered this asteroid before it struck, be it five months or even a week in advance, it would have been wise to send out a call for people to stay away from windows, Boslough said. 

In an October 1 online version of Acta Astronautica, a journal sponsored by the International Academy of Astronautics, Boslough has written about airburst warning and response, concluding that it is "virtually certain" that the next destructive Near Earth Object (NEO) event will be an airburst.

"Because early warning and civil defense will almost certainly be needed long before the first deflection is ever required, the credibility of the planetary defense community and its recommendations will be put to its first serious test by an airburst," Boslough said.

In his Acta Astronautica paper, Boslough has proposed an "airburst warning scale" to assist decision makers.

Misinterpreted attack

Also observing the Chelyabinsk episode, but from space, were U.S. government sensors. They, too, caught the affair, with that data released to the scientific community.

"If you compare some of these numbers to our estimates, they are different. It is worthwhile starting to consider these sorts of events as ground truth," Boslough told the DPS gathering.

Boslough underscored a concern voiced to Congress several years ago by Pete Worden, then deputy director for operations at the U.S. Space Command, now director of the NASA Ames Research Center near Silicon Valley, Calif. One of the largest potential threats associated with an airburst is the risk that it could be misunderstood as a preemptive attack launched by one country at another, Worden had said.

"I always thought that was a little exaggerated," Boslough said, until he watched a number of videos taken of the Chelyabinsk blast.

"Say that this had happened on an overcast day, where nobody actually saw the streak across the sky. Then you see smoke, hear a large explosion and a lot of things that sound like artillery fire," Boslough said. Then imagine it's over a place that's already politically unstable, he said.

"One of the biggest threats could be that this might lead to a counterattack of somebody because something was misconstrued," Boslough said.

Source of Article: Space.com