And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
Total lunar eclipse captured January 20-21, 2000. (Courtesy of Mr. Eclipse/Fred Espenak)
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Don’t say we didn’t warn you ahead of time! The upcoming total lunar eclipse will happen on June 15, 2011… and it’s a rare one. This time the Moon will pass directly through the center of the Earth’s shadow cone – an event that hasn’t happened in 11 years and won’t happen again until 2018. The eclipse visibility path will be over Africa, and Central Asia, visible rising over South America, western Africa, and Europe, and setting over eastern Asia. In western Asia, Australia and the Philippines – visible just before sunrise. But before you just read on to another article because you can’t see it from where you live, remember I’ve got a few tricks up my sleeve…
Thanks to this fantastic magic we call the Internet, all you need to do is tune into our friends around the world! The first listing of our live eclipse broadcasters will be Astronomylive.com. Coordinating the eclipse project and different activities for this year is Mohan Sanjeevan, a science and science fiction writer from India. Since May 2011, Mohan volunteers as the Event & Broadcast Organizer of AstronomyLive covering his country. But Mohan is more than just a coordinater, he’s also involved in other venues like writing poetry – including science poems (freelance science writing for more than twenty years; writer of nano science and tech articles for Nano Digest, a monthly magazine from India), popularization of science and creating awareness on global warming, alternative sources of energy and making the planet a more livable place. Space and astronomy are his natural areas of interest. To top it off, Sanjeevan is also a researcher – full of implementable ideas for space and future technologies.
AstronomyLive is a center for LIVE astronomy and you can participate, too! Host your broadcasts of various types on this free service. Amateur astronomers, professional astronomers, observatories, astronomy associations and more are all very welcome. The current team consists of Sander Klieverik, Voskuh and Dennis from the Netherlands, LesD from the United States, Mohan Sanjeevan, Aakanksha, Prof. M. Jothi Rajan, Jhon Kennedy, Bhaskar, Abhilasha and Sanyam Kumar Shrivastava from India. All of these great people came together to share the view with you!
And there’s more…
A free, live webcast from Bareket Observatory in Israel will also feature the total lunar eclipse on June 15, 2011. How do you get there? Simply click on this link for the Bareket Observatory Live Eclipse Broadcast! The hardworking group in Israel invite you to discover the Moon during the eclipse using hands-on eclipse activities. Conduct your own science projects using the live lunar eclipse feed! What a great opportunity for your students, family and friends!
The great folks at Bareket Observatory have expanded tremendously over the years and now they’re pleased to announce the launch of the Astro-Edu Network, a free state-of-the-art astronomy education database for teachers, students and the general public. Among the goals of AStro-Edu is increased communication and understanding within the population of the Middle East using astronomy as the catalyst. Astro-Edu net can be translated to more than 60 different languages using the integrated translation module (move your cursor over the flag in the upper left to translate the materials).
Lunar Eclipse Timing Chart
So don’t sit out the total lunar eclipse on June 15, 2011 – 17.00 – 23.00 UTC (GMT). Be sure to enjoy the event with our friends around the world!
This is one of the Tagish Lake meteorite fragments. Credit: Michael Holly, Creative Services, University of Alberta
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We’re all familiar with the hypothesis of panspermia – that life can be “seeded” from the contents of asteroids, comets and planetoids vis-a-vis meteorite impacts – but so far no direct evidence has been found. So why should we even consider meteorites to be potential parents? The truth is out there – they contain the essentials – right down to amino acids. Up until now, what we’ve recovered has been considered structured. Then along came Tagish Lake…
In January, 2000, a large meteoroid exploded in Earth’s atmosphere over northern British Columbia, Canada, resulting in a debris fall over frozen Tagish Lake. It was a rare observed fall, and the meteorites were meticulously gathered, documented and preserved in their frozen state. The reason was twofold: to preserve the integrity of the space stones and to ensure no contamination could occur either to Earth or to the specimens.
“The Tagish Lake meteorite fell on a frozen lake in the middle of winter and was collected in a way to make it the best preserved meteorite in the world,” said Dr. Christopher Herd of the University of Alberta, Edmonton, Canada, lead author of a paper about the analysis of the meteorite fragments published June 10 in the journal Science.
For meteorite collectors, we’re well aware of the value of an observed fall and equally aware of the documentation needed to make a meteorite valuable both to market and scientific study. It’s more than just writing down the date and time of the observation and where the fragments were collected. To be done properly, the field needs to be measured. Each fragment needs to be photographed in the position in which it was found. The depth measured and more. Nothing is left to speculation.
“The first Tagish Lake samples – the ones we used in our study that were collected within days of the fall – are the closest we have to an asteroid sample return mission in terms of cleanliness,” adds Dr. Michael Callahan of NASA’s Goddard Space Flight Center in Greenbelt, Md., a co-author on the paper.
What the scientists found was the Tagish Lake meteorites are rich in carbon – and contain an assortment of organic matter including amino acids. While these “building blocks of life” aren’t new to meteoritic structure, what was out of the ordinary was different pieces had greatly differing amounts of amino acids. This varies way off the beaten path.
“We see that some pieces have 10 to 100 times the amount of specific amino acids than other pieces,” said Dr. Daniel Glavin of NASA Goddard, also a co-author on the Science paper. “We’ve never seen this kind of variability from a single parent asteroid before. Only one other meteorite fall, called Almahata Sitta, matches Tagish Lake in terms of diversity, but it came from an asteroid that appears to be a mash-up of many different asteroids.”
The team set to work on the recovered fragments – identifying different minerals present in each meteorite. What they were looking for was to see how much each had been changed by the presence of water. What they found was the different fragments each had a different water signature not accounted for from their landing on Earth. Some had more interaction and others less. This alteration may explain the diversity in amino acid production.
“Our research provides new insights into the role that water plays in the modification of pre-biotic molecules on asteroids,” said Herd. “Our results provide perhaps the first clear evidence that water percolating through the asteroid parent body caused some molecules to be formed and others destroyed. The Tagish Lake meteorite provides a unique window into what was happening to organic molecules on asteroids four-and-a-half billion years ago, and the pre-biotic chemistry involved.”
How does this change the way we look at the panspermia theory? If future falls continue to show this widespread variability, scientists are going to have to be a bit more reserved in their judgements about whether or not meteorites could deliver enough bio-molecules to make the hypothesis viable.
“Biochemical reactions are concentration dependent,” says Callahan. “If you’re below the limit, you’re toast, but if you’re above it, you’re OK. One meteorite might have levels below the limit, but the diversity in Tagish Lake shows that collecting just one fragment might not be enough to get the whole story.”
While the Tagish Lake samples are undoubtedly some of the most carefully preserved specimens collected so far, there is still a possibility of contamination from both Earth atmosphere and their lake landing. But don’t simply write off these new findings just yet. In one fragment, the amino acid abundances were high enough to show they were made in space by analyzing their isotopes. These versions of elements with different masses can tell us a lot more about the story. For example, the carbon 13 found in the Tagish Lake samples is a much heavier, and less common, variety of carbon. Because amino acids prefer lighter forms of carbon, the enriched and heavier carbon 13 deposits were most likely created in space.
“We found that the amino acids in a fragment of Tagish Lake were enriched in carbon 13, indicating they were probably created by non-biological processes in the parent asteroid,” said Dr. Jamie Elsila of NASA Goddard, a co-author on the paper who performed the isotopic analysis.
The team compared their results with researchers at the Goddard Astrobiology Analytical Lab for their expertise with the difficult analysis. “We specialize in extraterrestrial amino acid and organic matter analysis,” said Dr. Jason Dworkin, a co-author on the paper who leads the Goddard laboratory. “We have top-flight, extremely sensitive equipment and the meticulous techniques necessary to make such precise measurements. We plan to refine our techniques with additional challenging assignments so we can apply them to the OSIRIS-REx asteroid sample return mission.”
[/caption]Back in 2009, Cirque du Soleil founder Guy Laliberte fired up the imaginations of would-be astronauts the world round when he paid an estimated $35 million dollars to spend 12 days aboard the International Space Station How many of us who are too large, too small or too out of physical shape to be a space traveller cheered when a rather “ordinary” human took place in space? Well, get in line for the next adventure… because just a mere $28,750,000 might buy you a ticket for a 30-day stay in Earth orbit.
Away from the glitz of Las Vegas, real estate developer Robert Bigelow is making use of the quiet Mojave Desert setting to solidify plans which border on the down-right incredible. His Bigelow Aerospace company owns 50 acres of barren land with buildings that aren’t much different than neighboring contractors – with the exception of high security. So why would these unassuming structures need armed security guards with futuristic alien patches on their uniforms?
Because he’s building the first space hotel.
These high-tech, low-cost inflatable space stations may very well be our future. As Bigelow believes, we’ll need a place to stay if we’re to further our studies in space – so why not in affordable accommodations? Bigelow has amassed his terrestrial wealth over his lifetime by providing rooms here, and the last 15 years have seen him invest approximately $210 million of his own money towards futuristic plans. In the long run, he’s willing to put forward up to $500 million to see his project through. His goal is to prove that space is a safe place for those willing to make the jump.
“We have a way of building stations that are far less expensive, far more safe and can be built more quickly,” says Bigelow. “And the timing is right.”
According the the entrepreneur, he’s engaging more than a dozen nations and has “memorandums of understanding” from countries including Japan, the Netherlands, Singapore, Sweden, Australia and the United Kingdom. In February NASA Deputy Administrator Lori Garver visited Bigelow Aerospace’s plant in North Las Vegas, and the agency is currently evaluating the company’s expandable modules for use as expansions to the International Space Station.
While it would be easy to write off such grand schemes as another of Bigelow’s “big” adventures, these inflatable space habitats are founded in solid technology. Bigelow’s prototypes have been orbiting Earth since 2006. His expansion of the desert plant will provide at least double the amount of work space, allowing him to construct a a scale model of the Sundancer, the first habitat he plans to launch into space. And when that’s done, he’ll build a model of its big brother, the BA330: At 11,600 cubic feet, it has nearly as much volume as the entire ISS!
When can we expect to book a room with a real view? Bigelow expects to have a fully functioning station in orbit by 2016 and to begin charging rent for it. While a little less than a million dollars a night isn’t going to exactly threaten Super 8 rates, one thing we can look forward to is knowing exactly what lights they’ll leave on…
Spirit’s last panoramic from Mars was taken during February 2010 before her death. Featured on Astronomy Picture of the Day (APOD) on 30 May 2011. Spirit’s final panoramic picture show from Mars was snapped on Sol 2175 in February 2010 before entering hibernation mode in March 2010 just prior to the onset of her 4th Martian winter. Spirit was just 500 feet from her next science target - dubbed Von Braun – center of the mosaic. The Columbia Hills form the backdrop to the mosaic from Spirits final resting place. Spirit never awoke. NASA ceased all communications attempts with Spirit on May 25, 2011. Credit: Mosaic by Marco De Lorenzo and Ken Kremer, images NASA/JPL/Cornell University.
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Scientists leading NASA’s Mars rover team have selected “Spirit Point” as the name for the spot where the “Opportunity” Mars rover will arrive at her next destination – Endeavour Crater. The site was named in honor of the death of the “Spirit” Mars Exploration Rover, which NASA recently declared has ceased all communications with Earth.
Spirit’s passing comes after more than six highly productive years roving the surface of the red planet as humankind’s surrogate. NASA concluded the last attempt to communicate with Spirit in a transmission on May 25, 2011.
“First landfall at Endeavour will be at the southern end of Cape York [at Spirit Point],” Steve Squyres told me. Squyres of Cornell University, Ithaca, N.Y., is principal investigator for the rovers. Read tributes from the Spirit rover science team below.
In memory of Spirit, the last panorama she snapped on Sol 2175 in February 2010 was featured on Astronomy Picture of the Day (APOD) on May 30, 2011 and is the lead image here. The photo mosaic was created by Marco Di Lorenzo and Ken Kremer and shows some of the last scenes that Spirit ever photographed.
Spirit approaches von Braun mound in April 2009
This mosaic of images was collected on Sol 1869 in April 2009 as Spirit approached a mysterious circular volcanic mound known as Von Braun, at left. Foreground at center, left ahead shows where Spirit became stuck in a concealed sand trap of slippery, water related sulfate minerals lying adjacent to the eroded volcanic plateau named Home Plate. Columbia Hills in the background.
Mosaic Credit: Kenneth Kremer/Marco Di Lorenzo/NASA/JPL/Cornell
Endeavour’s massive rim consists of a series of ridges. Cape York is a 400 foot wide (120 meters) rim fragment at the western edge of Endeavour. Opportunity should reach “Spirit Point” before the end of this year, 2011.
“Spirit Point” was chosen as the site at Endeavour to commemorate the scientific achievements of Opportunity’s twin sister “Spirit”. Endeavour Crater was determined to be Opportunity’s long term destination nearly three ago after she departed the environs of Victoria crater.
“The Initial exploration plan will be decided when we get closer. The [science] priorities will depend on what we find,” Squyres added.
Since August 2008, the blistering pace of Opportunity’s long overland trek of about 11 miles (18 kilometers) has brought the golf cart sized robot to within about 2 miles (3 kilometers) of the rim of the humongous Endeavour crater – some 14 miles (22 kilometers) in diameter. Endeavour is more than 20 times wider than Victoria crater and by far the largest feature the Opportunity will ever explore – see route maps below.
This oblique view with moderate vertical exaggeration shows the portion of the rim of Endeavour crater given the informal name "Spirit Point." This is the location where the team operating NASA's Mars Exploration Rover Opportunity plans to drive the rover to its arrival at the Endeavour rim. As of mid-June 2011, Opportunity was about 2 miles away from the rim of Endeavour. Credit: NASA/JPL-Caltech/Univ. of Arizona
“Spirit achieved far more than we ever could have hoped when we designed her,” according to Squyres in a NASA statement. “This name will be a reminder that we need to keep pushing as hard as we can to make new discoveries with Opportunity. The exploration of Spirit Point is the next major goal for us to strive for.”
The imaging team of Marco Di Lorenzo and Ken Kremer created a series of Spirit photomosaics from publically available images to illustrate the location and hazardous nature of Spirits final resting place – which fortuitously turned out to be a scientific goldmine revealing new insights into the flow of liquid water on Mars billions of years ago.
Mosaic of microscopic images of Spirit’s underbelly on Sol 1925 in June 2009
Mosaic shows predicament of being stuck at Troy with wheels buried in the sulfate-rich Martian soil. This false color mosaic has been enhanced and stretched to bring out additional details about the surrounding terrain and embedded wheels and distinctly shows a pointy rock perhaps in contact with the underbelly.
Mosaic Credit: Marco Di Lorenzo/ Kenneth Kremer/NASA/JPL/Cornell
The western rim of Endeavour possesses geological deposits far older than any Opportunity has investigated before and which may feature environmental conditions that were more conducive to the potential formation of ancient Martian life forms.
Spirits last transmissions to Earth took place in March 2010, before she entered hibernation mode due to ebbing solar power and succumbed to the likely damaging effects of her 4th Martian winter.
Spirit was closing in on her next science target, a mysterious volcanic feature named Von Braun, when she became mired in a sand trap named “Troy” on the outskirts of the eroded volcano named “Home Plate, just about 500 feet away. See our mosaics.
Spirit embedded at sand trap in February 2010 on Sol 2174
Numerous attempts by the rover team failed to extricate Spirit from the sand trap at Troy in which she became mired in May 2009 on the western edge of Home Plate. Mosaic shows last robotic arm maneuver before hibernation and above bright toned soil containing hydrated sulfates. Mosaic Credit: Marco Di Lorenzo/ Kenneth Kremer/ NASA/JPL/Cornell
Unable to escape and absent of sufficient power to run critical survival heaters, Spirit experienced temperatures colder than ever before that probably crippled fragile electronics components and connections and prevented further communications – although no one knows for sure.
NASA’s twin rovers Spirit and Opportunity have been exploring the Martian terrain on opposite sides of the red planet since the dynamic duo successfully landed over 7 years ago in January 2004.
Both robots were expected to last just three months but have accumulated a vast bonus time of exploration and discovery in numerous extended mission phases.
*** Several top members of the rover science team kindly provided me some comments (below) to sum up Spirits achievements and legacy and what’s ahead for Opportunity at Endeavour.
Ray Arvidson of Washington University, St Louis, Deputy Principal Investigator for the rovers:
“Spirit’s last communication with Earth was in March 2010 as the southern hemisphere winter season began to set in, the sun was low on the horizon, and the rover presumably stopped communicating to use all available solar power to charge the batteries.
Von Braun was one of the two destinations Spirit was traveling to when the rover became embedded in soft sands in the valley to the west of Home Plate.
Von Braun is a conically-shaped hill to the south of Home Plate, Inner Basin, Columbia Hills. Goddard is an oval-shaped shallow depression to the west of von Braun and was the second area to be visited by Spirit. Both von Braun and Goddard are suspected to be volcanic features.
Spirit is the brightest spot in this image taken on 31 March 2011 from Mars orbit. Spirit is gleaming in the sun beside Home Plate inside Gusev Crater. The solar panels are not covered by an optically thick layer of dust. Spirit last communicated on 22 March 2010. Credit: NASA/JPL/UA
During Spirit’s six year and two month mission the vehicle acquired remote sensing and in-situ observations that conclusively demonstrated that the ancient Columbia Hills in Gusev Crater expose materials that have been altered in water-related environments, including ground water corrosion and generation of sulfate and opaline minerals in volcanic steam vents and perhaps hydrothermal pools.
Together with its sister rover, Opportunity, the Mars Exploration Rover Mission, was designed to “follow the water” and return data that would allow us to test the hypothesis that water was at and near the surface during previous epochs.
Opportunity is still exploring the evidence in Meridiani for ancient shallow lakes and is on the way to outcrops on the rim of Endeavour crater, a ~20 km wide crater that exposes the old Noachian crust that shows evidence from orbital data for hydrated clay minerals.
These two rovers have performed far beyond expectations, unveiled the early, wet history of Mars, and have made an enormous scientific return on investment.”
Steve Squyres of Cornell University, Ithaca, N.Y., Principal Investigator for the rovers:
“Our best hope for hearing from Spirit was last fall. When that didn’t happen, we began a long, careful process of trying every possible approach to re-establishing contact. But it slowly became clear that it was unlikely, and I personally got used to the idea that Spirit’s mission was probably over several months ago.
Once that right front wheel failed, Spirit’s days were numbered in that kind of terrain. It wouldn’t have made any difference if we had tried to move Spirit sooner. We were very lucky to have survived as long as we did.
One of the lessons learned is to try to keep the wheels from failing.
It’s very sad to lose Spirit. But two things have softened the blow. First we’ve had a long time to get used to the idea. Second, even though Spirit is dead, she died an honorable death. If we’d lost her early in the mission, before she accomplished so much, it would have been much harder. But she accomplished so much more than any of us expected, the sadness is very much tempered with satisfaction and pride.
The big scientific accomplishments are the silica deposits at Home Plate, the carbonates at Comanche, and all the evidence for hydrothermal systems and explosive volcanism. What we’ve learned is that early Mars at Spirit’s site was a hot, violent place, with hot springs, steam vents, and volcanic explosions. It was extraordinarily different from the Mars of today.
Opportunity is heading at high speed for the rim of Endeavour Crater. First landfall will be at the southern end of Cape York. She should be there in not too many more months.
It hasn’t yet been decided where Opportunity will attempt to climb up Endeavour… we’ll see when we get there.
The phyllosilicates are a high priority, but the top priority depends on what we find.
The yellow line on this map shows where NASA's Mars Rover Opportunity has driven from the place where it landed in January 2004 -- inside Eagle crater, at the upper left end of the track -- to a point about 2.2 miles (3.5 kilometers) away from reaching the rim of Endeavour crater. Credit: NASA/JPL-Caltech/MSSS
I hope Spirits legacy will be the inspiration that people, especially kids, will take away from Spirit’s mission. I have had long, thoughtful conversations about Spirit with kids who have had a rover on Mars as long as they can remember. And my fondest hope for Spirit is that somewhere there are kids who will look at what we did with her, and say to themselves “well, that’s pretty cool… but I bet when I grow up I can do better. That’s what we need for the future of space exploration.
Spirit existed, and did what she did, because of the extraordinary team of engineers and scientists who worked so hard to make it possible. It’s a team that I’m incredibly proud to have been a small part of. Working with them has been quite literally the adventure of a lifetime.”
Jim Bell of Arizona State University, lead scientist for the rovers Pancam stereo panoramic camera:
“It is with a bittersweet sense of both sadness and pride that NASA announced the official end of the mission for the Mars Exploration Rover Spirit.
The Spirit team has seen the end coming since communications were lost with the rover in March 2010. Mission engineers made heroic efforts to reestablish contact. In the end Spirit was conquered by the extremely cold Martian winter and its two broken wheels, which prevented its dusty solar panels from pointing toward the Sun.
But what a mission! Designed to last 90 days, Spirit kept going for more than six years, with the team driving the rover almost 5 miles (8 km) across rocky volcanic plains, climbing rugged ancient hills, and scurrying past giant sand-dune fields. It eventually spent most of the mission near the region known as Home Plate, which is full of layered, hydrated minerals.
Data from the rover enabled dozens of scientific discoveries, but three stand out to me as most important:
Hydrated sulfate and high-silica soils in the Columbia Hills and around Home Plate.
These minerals, and the environment in which they occur (Home Plate is a circular-shaped, finely layered plateau that may be the eroded remains of a volcanic cone or other hydrothermal deposit), tell us that at some point in the past history of Gusev there was liquid water and there were heat sources — two key ingredients needed to consider the area habitable for life as we know it.
Carbonate minerals in some of the rocks within the Columbia Hills.
Carbonates were expected on Mars, if indeed the climate was warmer and wetter in the past. However, their detection has been elusive so far. Indeed, the Spirit team had to work hard to uncover the signature of carbonates years after the rover made the measurements. As the analysis continues the results for Mars in general could be profound.
An incredible diversity of rock types, from all over Mars, that Spirit was able to sample in Gusev crater.
Some of the rocks appear to be from local volcanic lava flows or ash deposits. But others have likely been flung in to the area over time by distant impacts or volcanoes, and a few even appear to be meteorites, flung in from outer space. Spirit’s instruments provided the team with the ability to recognize this amazing diversity, and thus to learn much more about Mars in general, not just Gusev in particular.
Spirit also helped us test an experiment: If we put all the rover’s images out on the Web for everyone in the world to see, in near real-time, would people follow along? They did!
I wonder if, maybe 10 or 15 years from now, I’ll meet some young colleagues who were turned on to space exploration by being able to check out the latest Spirit images from Mars from their classroom, or living room, every day when they were a kid. That would be extremely satisfying — and a great testament to the power of openly sharing data from space exploration missions like Spirit’s.
Meanwhile, Opportunity continues to rove on to city-size Endeavour crater, where orbital measurements have identified, for the first time in either rover’s mission, the signatures of clay minerals in the crater’s rim. Clays are also formed in water, but in less acidic, perhaps more life-friendly water than the sulfates that Opportunity has been mapping thus far.”
Rob Manning, Jet Propulsion laboratory, Pasadena, CA., Mars Rover Spacecraft System Engineering team lead
“Although Opportunity has proven her endurance, Spirit was the one we struggled with the hardest to get what she earned. Suffering from late repair and modification, a blown fuse in her power system and with possibly damaged circuits, she was very late getting out the door and onto the pad in Florida.
Unlike Opportunity, whose Hematite-laden Meridiani destination had been established long before launch, Spirit was launched with a great deal of uncertainty on where she would find herself on Mars. Would it be the flat and safe plains of Elysium? Would the intriguing but rough ancient Gusev crater with what appears to have been an ancient river flowing into a giant but now dry lake?
If Opportunity failed to get on her way to Mars, would her destination become Meridiani? Would Spirit have also been as lucky to find herself bouncing into a tiny rock-outcropped crater as Opportunity had?
Only after the successful launch of Opportunity followed by further successful rocket and airbag tests to confirm that the landing system design would work in the rougher terrain inside Gusev crater allowed us to seal her fate and her permanent home.
She would go Gusev and test the Gusev lake hypothesis. Sadly the surface of Gusev where she came to rest revealed a meteor impact-tilled lake of ancient lava. Any signs of ancient water lake beds and other fantastic discoveries would have to wait until she surmounted many more obstacles including summiting a formidable hill her designers never intended her to attempt.
Spirit, her designers, her builders, her testers, her handlers and I have a lot to be thankful for.
That NASA, the congress and the public were willing to trust us with this daunting feat is perhaps a statement about the persistent spirit of discovery that remains in all of us.
I think that Spirit is alive and well.”
Map mosaic shows 7 Year and 30 Kilometer Long Journey of Opportunity approaching Endeavour Crater. Opportunity is being targeted to Spirit Point on the rim of Endeavour Crater, to honor her now dead sister. Photo mosaic of Santa Maria crater at top right was featured on Astronomy Picture of the Day on 29 January 2011. Mosaic shows Opportunity self portrait at the rim of Santa Maria where she investigated signatures of hydrated mineral deposits.
Mosaic Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Kenneth Kremer
The dark and light side of Iapetus. Credit: NASA/JPL/Space Science Institute
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Although Saturn’s moon Iapetus was first discovered in 1671 by Giovanni Cassini, its behavior was extremely odd. Cassini was able to regularly find the moon when it was to the west of Saturn, but when he waited for it to swing around to Saturn’s east side, it seemed to vanish. It wasn’t until 1705 that Cassini finally observed Iapetus on the eastern side, but it took a better telescope because the side Iapetus presented when to the east was a full two magnitudes darker. Cassini surmised that this was due to a light hemisphere, presented when Iapetus was to the west, and a dark one, visible when it was to the east due to tidal locking.
With the advances in telescopes, the reason for this dark divide has been the subject of much research. The first explanations came in the 1970’s and a recent paper summarizes the work done so far on this fascinating satellite as well as expanding it to the larger context of some of Saturn’s other moons.
The foundation for the current model of Iapetus’ uneven display was first proposed by Steven Soter, one of the co-writers for Carl Sagans Cosmos series. During a colloquium of the International Astronomical Union, Soter proposed that micrometeorite bombardment of another of Saturn’s moons, Pheobe, drifted inwards and were picked up by Iapetus. Since Iapetus keeps one side facing Saturn at all times, this would similarly give it a leading edge that would preferentially pick up the dust particles. One of the great successes of this theory is that the center of the dark region, known as the Cassini Regio, is directly situated along the path of motion. Additionally, in 2009, astronomers discovered a new ring around Saturn, following Phoebe’s retrograde orbit, although slightly interior to the moon, adding to the suspicion that the dust particles should drift inwards, due to the Poynting-Robertson effect.
In 2010, a team of astronomers reviewing the images from the Cassini mission, noted that the coloration had properties that didn’t quite fit with Soter’s theory. If deposition from dust was the end of the story, it was expected that the transition between the dark region and the light would be very gradual as the angle at which they would strike the surface would become elongated, spreading out the incoming dust. However, the Cassini mission revealed the transitions were unexpectedly abrupt. Additionally, Iapetus’ poles were bright as well and if dust accumulation was as simple as Soter had suggested, they should be somewhat coated as well. Furthermore, spectral imaging of the Cassini Regio revealed that its spectrum was notably different than that of Phoebe. Another potential problem was that the dark surface extended past the leading side by more than ten degrees.
Revised explanations were readily forthcoming. The Cassini team suggested that the abrupt transition was due to a runaway heating effect. As the dark dust accumulated, it would absorb more light, converting it to heat and helped to sublimate more of the bright ice. In turn, this would reduce the overall brightness, again increasing the heating, and so on. Since this effect amplified the coloration, it could explain the more abrupt transition in much the same way as adjusting the contrast on an image will sharpen gradual transitions between colors. This explanation also predicted that the sublimated ice could travel around the far side of the moon, freezing out and enhancing the brightness on the other sides as well as the poles.
To explain the spectral differences, astronomers proposed that Phoebe may not be the only contributor. Within Saturn’s satellite system, there are over three dozen irregular satellites with dark surfaces which could also potentially contribute, altering the chemical makeup. But while this sounded like a tantalizingly straight-forward solution, confirmation would require further investigation. The new study, led by Daniel Tamayo at Cornell University, analyzed the efficiency with which various other moons could produce dust as well as the likelihood with which Iapetus could scoop it up. Interestingly, their results showed that Ymir, a mere 18 km in diameter, “should be roughly as important a contributor of dust to Iapetus as Phoebe”. Although none of the other moons, independently looked to be as strong of sources for dust, the sum of dust coming the remaining irregular, dark moons was found to be at least as important as either Ymir or Phoebe. As such, this explanation for the spectral deviation is well grounded.
The last difficulty, that of spreading dust past the leading face of the moon, is also explained in the new paper. The team proposes that eccentricities in the orbit of the dust allow it to strike the moon at odd angles, off from the leading hemisphere. Such eccentricities could be readily produced by solar radiation, even if the orbit of the originating body was not eccentric. The team carefully analyzed such effects and produced models capable of matching the dust distribution past the leading edge.
The combination of these revisions seem to secure Soter’s basic premise. A further test would be to see if other large satellites like Iapetus also showed signs of dust deposition, even if not so starkly divided since most other moons lack the synchronous orbit. Indeed, the moon Hyperion was found to have darker regions pooling in its craters when Cassini few by in 2007. These dark regions also revealed similar spectra to that of Cassini Regio. Saturn’s largest moon, Titan is also tidally locked and would be expected to sweep up particles on its leading edge, but due to its thick atmosphere, the dust would likely be spread moon-wide. Although difficult to confirm, some studies have suggested that such dust may help contribute to the haze Titan’s atmosphere exhibits.
Centaurus A - the closest galaxy with an active galactic nucleus - a mere 10-16 million light years away. Now I wonder where all those ultra high energy cosmic rays are coming from. Hmmm...
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Cosmic rays are really sub-atomic particles, being mainly protons (hydrogen nuclei) and occasionally helium or heavier atomic nuclei and very occasionally electrons. Cosmic ray particles are very energetic as a result of them having a substantial velocity and hence a substantial momentum.
The Oh-My-God particle detected over Utah in 1991 was probably a proton traveling at 0.999 (and add another 20 x 9s after that) of the speed of light and it allegedly carried the same kinetic energy as a baseball traveling at 90 kilometers an hour.
Its kinetic energy was estimated at 3 x 1020 electron volts (eV) and it would have had the collision energy of 7.5 x 1014 eV when it hit an atmospheric particle – since it can’t give up all its kinetic energy in the collision. Fast moving debris carries some of it away and there’s some heat loss too. In any case, this is still about 50 times the collision energy we expect the Large Hadron Collider (LHC) will be able to generate at full power. So, this gives you a sound basis to scoff at doomsayers who are still convinced that the LHC will destroy the Earth.
Now, most cosmic ray particles are low energy, up to 1010 eV – and arise locally from solar flares. Another more energetic class, up to 1015 eV, are thought originate from elsewhere in the galaxy. It’s difficult to determine their exact source as the magnetic fields of the galaxy and the solar system alter their trajectories so that they end up having a uniform distribution in the sky – as though they come from everywhere.
But in reality, these galactic cosmic rays probably come from supernovae – quite possibly in a delayed release process as particles bounce back and forth in the persisting magnetic field of a supernova remnant, before being catapulted out into the wider galaxy.
And then there are extragalactic cosmic rays, which are of the Oh-My-God variety, with energy levels exceeding 1015 eV, even rarely exceeding 1020 eV – which are more formally titled ultra-high-energy cosmic rays. These particles travel very close to the speed of light and must have had a heck of kick to attain such speeds.
Left image: The energy spectrum of cosmic rays approaching Earth. Cosmic rays with low energies come in large numbers from solar flares (yellow range). Less common, but higher energy cosmic rays originating from elsewhere in the galaxy are in the blue range. The least common but most energetic extragalactic cosmic rays are in the purple range. Right image: The output of the active galactic nucleus of Centaurus A dominates the sky in radio light - this is its apparent size relative to the full Moon. It is likely that nearly all extragalactic cosmic rays that reach Earth originate from Centaurus A.
However, a perhaps over-exaggerated aura of mystery has traditionally surrounded the origin of extragalactic cosmic rays – as exemplified in the Oh-My-God title.
In reality, there are limits to just how far away an ultra-high-energy particle can originate from – since, if they don’t collide with anything else, they will eventually come up against the Greisen–Zatsepin–Kuzmin (GZK) limit. This represents the likelihood of a fast moving particle eventually colliding with a cosmic microwave background photon, losing momentum energy and velocity in the process. It works out that extragalactic cosmic rays retaining energies of over 1019 eV cannot have originated from a source further than 163 million light years from Earth – a distance known as the GZK horizon.
Recent observations by the Pierre Auger Observatory have found a strong correlation between extragalactic cosmic rays patterns and the distribution of nearby galaxies with active galactic nuclei. Biermann and Souza have now come up with an evidence-based model for the origin of galactic and extragalactic cosmic rays – which has a number of testable predictions.
They propose that extragalactic cosmic rays are spun up in supermassive black hole accretion disks, which are the basis of active galactic nuclei. Furthermore, they estimate that nearly all extragalactic cosmic rays that reach Earth come from Centaurus A. So, no huge mystery – indeed a rich area for further research. Particles from an active supermassive black hole accretion disk in another galaxy are being delivered to our doorstep.
WISE image of the "Elephant Trunk" nebula. NASA/JPL-Caltech/WISE Team.
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The stellar wind, that is! This beautiful image, taken by NASA’s Wide-Field Infrared Explorer (WISE) shows a vast ring of interstellar dust and gas being forced outwards by the wind and radiation from a massive star.
The star, HR8281, is located in the center of the image, the topmost star in a small triangular formation of blue stars to the upper left of the tip of a bright elongated structure – the end of the “elephant trunk” that gives the nebula its name. The star may not look like much, but HR8281’s powerful stellar wind is what’s sculpting the huge cloud of dust into the beautiful shapes seen in this infrared image.
Located 2,450 light-years from Earth, the Elephant’s Trunk Nebula spans 100 light-years. The “trunk” itself is about 30 light-years long. (That’s about, oh… 180 trillion miles!)
Structures like this are common in nebulae. They are formed when the stellar wind – the outpouring of ultraviolet radiation and charged particles that are constantly streaming off stars – blows away the gas and dust near a star, leaving only the densest areas. It’s basically erosion on a massive interstellar scale.
The tip of the "trunk" and the triangle of stars, the topmost of which is HR8281.
It’s not just a destructive process, though. Within those dense areas new stars can form… in fact, in the bright tip of the trunk above a small dark spot can be seen. That’s an area that’s been cleared by the creation of a new star. When a baby star “ignites” and its nuclear fusion factory turns on, its stellar wind clears away the dust and gas in the cloud it was formed from. Nebulae aren’t just pretty clouds in space… they’re stellar nurseries!
The red-colored stars in this image are other newborn stars, still wrapped in their dusty “cocoons”.
The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust.
The streak on Google Mars misinterpreted as a secret Mars base.
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It’s time for another episode of “Conspiracy Theory of the Week.” This one involves a supposed secret space station on Mars. The You Tube video showing “Bio Station Alpha” (below) went viral and was even reported on some mainstream media outlets. The station is supposedly a 700 ft x 150 ft structure on Mars and by some accounts is colored white with blue and red stripes. It was found on Google Mars by an “armchair astronaut” and breathless conspiracy bloggers have touted this as the most important discovery on Mars yet, and “proof!” that NASA is hiding their activities.
In reality, this is not a space station, a Mars base or any type of structure – created or natural — on the surface of the Red Planet. What shows up in this location on Google Mars is just a smattering of about 11 bad pixels from data dropout – a linear streak artifact likely caused by a cosmic ray hitting the Mars Express spacecraft while it was taking the image – and then that smudge has been badly distorted through image processing when it became part of Google Mars.
Here’s the image that is seen on Google Mars after processing, which includes very noticeable compression artifacts:
And now here’s the original image taken by the Mars Express High Resolution Stereo Camera image (H5620_0000_ND), taken on May 18, 2008 (and here’s the link to the original image):
Original Mars Express HRSC image of the location in question on Mars. Credit: ESA
This image really makes it clear this is an image artifact from a cosmic ray hit.
Here’s the same location taken by the MRO Context Camera (CTX) on January 25, 2010 (a crop of the same location as seen above from the original large CTX image, available here):
MRO's Context Camera (CTX) image MRO CTX B17_016407_2528_XN_72N029W of the same location. Credit: MSSS
In this image, each pixel represents a distance of about 6.25 meters, a higher resolution than what is available from the Mars Express spacecraft, which takes images at 10 meters per pixel. Obviously, there is no structure or anything unusual at that location, except for the northern polar sand dunes.
Harrison explained that the CTX acquires grayscale (black & white) images at 6 meters per pixel scale over a swath 30 kilometers wide and provides context images for the MRO HiRISE and CRISM cameras, which can take even higher resolution images. It is used to monitor changes occurring on the planet, and help the science team select critical science targets. The team at Malin Space Science Systems pores over the images looking for anything unusual. In this case, at this location, they found nothing.
“Every day, the images we acquired with CTX and MARCI the previous day are inspected by multiple sets of eyes,” Harrison told Universe Today. “We look at every single image for multiple reasons: checking the health of the instrument, monitoring weather conditions for future targeting of the cameras, and looking for anything geologically interesting.”
Harrison added that nearly all the operations folks on the team have Master’s degrees or Ph.D.s in geology or a related field.
“If we spot anything out of the ordinary, we look at previous images of the area, not just from CTX and MARCI, but from the Mars Global Survery’s Mars Orbiter Camera, the THEMIS VIS and IR on the Mars Odyssey spacecraft, the HRSC on Mars Express, and Viking,” Harrison said. “This lets us look at the features at different illumination angles, times of day, resolutions, etc. We know better than to speculate on something below the resolution of our cameras, so if we see something in CTX that’s worth following up on at a higher resolution, we ask HiRISE to shoot it. The same thing was true for MOC, following up on things observed in the low-resolution wide angle images with high-resolution narrow angle images.”
Clearly, this region has been imaged and examined previously, with absolutely nothing found by the top experts in the field. The region is so uninteresting that no one has requested for HiRISE — which can take images of 1-2 meters per pixel — to take any images of this area.
Harrison said CTX takes images of Mars that are up to 30 km wide and over 300 km long at a very high resolution. “This is a pretty big footprint with a relatively high resolution compared to previous cameras!” she said. “The size of that footprint has allowed us to cover over 60% of Mars at 6 meters per pixel in the 5 years MRO has been orbiting Mars. In addition to mapping, we use CTX to acquire stereo coverage of key areas, as well as to monitor hundreds of locations on Mars for changes such as new impact craters and dust activity.”
If there were something unusual on Mars, the people at NASA, ESA, MSSS and anyone monitoring Mars would have imaged this site repeatedly with the best cameras available. They would love to find something unusual, groundbreaking and front-page worthy, and if they did would be shouting it from the rooftops, not hiding it.
The folks at Dragon*Con have decided to decline having me as a guest this year. I already have my plane tickets, hotel booked, so I’m still going to go – I just signed up with a regular membership. It’s too bad, but then, this gives me the freedom to just enjoy the convention as a fan, and not have to participate in panels, help promote the convention through Universe Today, etc. I think we’re still going to do an episode of Astronomy Cast live, just because that’s so much fun. I’m bringing the whole family: wife, kids, even the mother-in-law. Anyway, you’ll see me lurking around the Astronomy Cast booth, or watching panels. It should be a fun vacation. 🙂 See you there!
