COMING EVENTS Public Observing Sunday Jan. 27 Sunday Feb. 24

Prairie Park Nature Center 8:00 PM

Monthly Meeting Friday FEB. 15 7:30 PM, 2001 Malott

President

Rick Heschmeyer rcjbm@sbcglobal.net

University Advisor Dr. Bruce Twarog btwarog@ku.edu

Webmaster Howard Edin

howard@howardedin.com

Observing Clubs Doug Fay

dfay@ku.edu

ALCOR William Winkler

billwink10@yahoo.com

Report from the Officers: The end-of-year celebration went well with refreshments and door prizes for everyone in attendance, including a lovely small telescope in need of a home. Our speaker was Dr. Roger Boyd, Professor Emeritus at Baker University, and the Director of the Baker Wetlands Science Center. Dr. Boyd discussed the history of the wet-lands, including the multigenerational involvement of his family in setting up and maintaining the site. Baker University has filed plans with

the Lawrence-Douglas County Planning Department to build a $1.2 million wetland education center near the wetlands that the university is creating as part of the miti-

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Volume 39 Number 01 January 2013

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INSIDE THIS ISSUE

Charlemagne (continued) 2

Clouds: Armchair Science 3

NASA Space Place 4

Free E-Books 5

Van Allen Probes - Results 6

Giant Star Makes Waves 7

Gigantic Galaxy Clusters 8

Galaxy Bullseye 9

Galaxy Cluster (continued) 10

Charlemagne (continued) 3

Of Local Interest Researcher points to Sun as likely source of eighth-century

'Charlemagne event' Until recently, the years 774 and 775 were best known for Charlemagne’s victory over the Lombards. But earlier this year, a team of scientists in Japan discovered a baffling spike in carbon-14 deposits within the rings of cedar trees that matched those same years. Because cosmic rays are tied to carbon-14 concentrations, scientists around the world have wondered about the cause: a nearby supernova, a gamma ray burst in the Milky Way or an intense superflare emanating from the Sun?

Now, Adrian Melott, professor of physics and astronomy at the University of Kansas and Brian Thomas, KU alumnus and professor of physics and astronomy at Washburn University, have examined the evidence and zeroed in on the likely source of the medieval cosmic ray bombardment — a coronal mass ejection from the Sun. Melott said the scientists, who originally discovered the carbon-14 spike and pub-lished their findings in the journal Nature, miscalculated the implied intensity of such an event, and they mistakenly ruled out the Sun as the cause of the radiation de-tected for the years 774-775.

“What they concluded was that the energy emitted by the Sun would have had to have been, say, 1,000 times larger than the Carrington event — the greatest solar flare ever known,” Melott said. “We just observed this simple mistake and corrected it, and the answer came out that it would be 10 or 20 times greater than the Carring-ton event in 1859. That means that this may be a more reasonable explanation. The Carrington event is the greatest in the last 200 years, and this would be the greatest thing in the last 1,300 years or so, so it becomes more reasonable.”

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A New Year’s Welcome to new AAL club member

ROB BURK

About the Astronomy Associates of Lawrence

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The club is open to all people interested in sharing their love for astronomy. Monthly meetings are typically on the second Fri-day of each month and often feature guest speakers, presentations by club members, and a chance to exchange amateur as-tronomy tips. Approximately the last Sunday of each month we have an open house at the Prairie Park Nature Center. Periodic

star parties are scheduled as well. For more information, please contact the club officers: president, Rick Heschmeyer at rcjbm@sbcglobal.net; webmaster, Howard Edin, at howard@howardedin.com; AlCor William Winkler, at

billwink10@yahoo.com; or faculty advisor, Prof. Bruce Twarog at btwarog@ku.edu. Because of the flexibility of the schedule due to holidays and alternate events, it is always best to check the Web site for the exact Fridays and Sundays when events

are scheduled. The information about AAL can be found at http://groups.ku.edu/~astronomy

Copies of the Celestial Mechanic can also be found on the web at http://groups.ku.edu/~astronomy/celestialmechanic

gation efforts for the South Lawrence Trafficway project. The plans call for a 10,000-square-foot center that will have a large display area, two classrooms, a kitchen, a gift shop and office space. The project also calls for a 3,000-square-foot mainte-nance building for the property and is set to be built near the main entrance of the wetlands area, which is at 1365 North 1250 Road. The new building will accommodate up to 170 people at a time for presentations and other related activities. Baker University is betting that the education center will draw interest from the general community, but will be a particularly popular place for school field trips. The relevance to AAL is that, as part of the final plan for the Science Center, Dr. Boyd has proposed construction of a public observatory at the Wetlands Science Center. His presentation included some basic designs for installation of a 12-16 inch scope with dome, as well as a concrete platform for potential use by individual observers with their own portable instruments. The response of the attendees was enthusiastically positive and led to immediate discussion of more up-to-date options for installing a scope/dome and for laying out a open area for public observing. It appears that this is a project that the club can easily get behind and contribute to through its expertise in state-of-the-art equipment for amateur astronomy, as well as the basics for designing a good ob-serving site for small telescopes. We will keep you posted as the discussions move forward and the design plans become more concrete. NEXT MONTH: The Astronomical League has a new observing program on OBSERVING STELLAR EVOLUTION. More on this in the next issue! Any suggestions for improving the club or the newsletter are always welcome.

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In addition, Melott noted that recent observations of stars similar to the Sun made by the Kepler satellite suggest that they are flaring at levels similar to that which they suggest — and higher — at average intervals of a few hundred to thousand years. Other explanations for the medieval radiation burst are highly improbable, according to the KU researcher. For instance, the scientists who discovered the carbon-14 spike ruled out the possibility of a nearby galactic supernova as a source, and Melott agrees with their conclusion.

“A supernova is basically a star that comes to the end of its life and produces a spectacular explosion,” said Melott. “But in order to produce effects like the ones seen in the tree rings, such a supernova would have had to have been within 100 light years or so. Such an event would have been blindingly bright in the sky, much brighter than a full moon. It would have been bright like that for months and could not have failed to be noted by every civilization on Earth. Being so close, there would be remnants of the explosion visible today, still expanding. Something so close could not have been missed.”

Melott believes a third possibility for the 774-775 burst of cosmic energy — a gamma ray burst — should have been considered by the original authors, even though he deemed it unlikely.

“A gamma ray burst comes from a small fraction of supernovae,” he said. “They result in a beaming of the radiation into two nar-row searchlight beams going out in opposite directions from the event. Now, because the radiation is so columnated, they can nail you from quite far away. They could be hundreds or even thousands of light years away and still nail us with enough radia-tion to produce the carbon-14 spike. It’s a possibility, but not a likely possibility, because these things happen with intervals of 10-15 million years on average. Is it likely that such a burst would have happened 1,200 years ago? Rare events do happen, but it would be very surprising. I don’t think it’s a likely explanation.”

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Armchair Science: Bag and Tag Glowing Galactic Clouds A new galactic game launches today that lets citizen scientists identify the glowing clouds where future stars will be born. The online experience, called Clouds, is a new addition to the Milky Way Project, where everyone can help astronomers to sort and measure our galaxy. Clouds features images and data from NASA's Spitzer Space Telescope and the Herschel Space Observatory, a European Space Agency mission with important participation from NASA.

In the rapid-fire game, players gauge whether a targeted section of a presented image is a cloud, a "hole" - an empty region of space - or something in between. The cataloging of these snapshots of the local cosmos will help astronomers learn more about the architecture and character of our home galaxy, the Milky Way.

The organizers of Clouds encourage astronomy enthusiasts to start playing now because with enough participa-tion, important insights into the Milky Way could come as soon as early next year.

"We're really excited to launch Clouds and see results back from our giant volunteer team of amateur scientists," said Robert Simpson, a postdoctoral researcher in astronomy at Oxford University, England and principal investi-gator of the Milky Way Project. "We think the community can blast through all these data fairly quickly. We may even be done by the spring and that would be an amazing result for citizen science."

Clouds joins its predecessor Milky Way Project game, Bubbles, as one of the many "crowdsourced" efforts under-way at Zooniverse, home to the Internet's biggest and most popular online citizen science projects.

The crowdsourcing concept involves having a lot of people evaluate the same image or pieces of data. A consen-sus decision on some aspect of the image is then reached through the collective "wisdom of crowds." Crowd-sourced citizen science becomes especially important when humans can do a better job at analyzing images or objects than a computer can. The Clouds game is an example of just such an exercise in which eyeballs and brains beat out cameras and computer algorithms.

The goal of Clouds is to tag the dense, cold cores of gas and dust known as infrared dark clouds. These clouds collapse under their own gravity and then burst forth as new stars. An empty region of space, however, can look rather like one of these dark clouds and deceive a computer accordingly. "Automated routines have tried to de-cide which of these objects are holes and which are true infrared dark clouds, but the task is often tricky and it takes a human eye to decide," said Simpson.

Clouds combines infrared observations from Herschel and Spitzer to reveal cool clouds and holes throughout the Milky Way's disk. The Herschel data, at a wavelength of 250 microns, appears in yellow throughout the game. The Spitzer data, at 8 microns, is rendered in blue.

Together with its companion Bubbles game, Clouds serves as another example of how Zooniverse makes cut-ting-edge scientific investigation freely available to the general public. "Citizen science through Zooniverse has been a real boon to research in fields ranging from astronomy to biology to history," noted Simpson. "We feel very fortunate to be able to send science work out to computer, tablet and smartphone screens and for people to col-laborate with us in a quest to better understand our universe."

For those interested in looking for infrared clouds and contributing to the Milky Way Project, visit the following link: http://www.milkywayproject.org To learn of other citizen science-based efforts, check out the Zooniverse: https://www.zooniverse.org

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Returning to the more-likely solar event, Melott said that something similar to the Charlemagne event would have disastrous consequences for today’s technology-dependent world. He said such an event could occur every one or two thousand years, but unpredictably and with only a few hours’ warning.

“You’d get a slight increase in skin cancer rates because of effects on the ozone layer,” said Melott. “You’d get a little bit of damage to food crops, but that’s not too serious — and it wasn’t for the Holy Roman Empire either. But we have a problem they didn’t, which is our technological level. When these things hit, the Earth’s magnetic field undergoes an interaction, and the magnetic field lines move, and that produces a current in wires. If you have a long power line, you can get a huge current. Transformers get overloaded, and they burn out. And you can lose a lot of transformers. Imagine the lights going off all over the developed world — not to come on for who knows how long — because you have to build more transformers. And how to you do that without electricity? It’s a real problem to prepare for it.”

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Partnering to Solve Saturn’s Mysteries

By Diane K. Fisher

From December 2010 through mid-summer 2011, a giant storm raged in Saturn’s northern hemisphere. It was clearly visible not only to NASA’s Cassini spacecraft orbiting Saturn, but also astronomers here on Earth—even those watching from their back yards. The storm came as a surprise, since it was about 10 years earlier in Saturn’s seasonal cycle than expected from observations of similar storms in the past. Saturn’s year is about 30 Earth years. Saturn is tilted on its axis (about 27° to Earth’s 23°), causing it to have seasons as Earth does. But even more surprising than the unseasonal storm was the related event that followed. First, a giant bubble of very warm material broke through the clouds in the region of the now-abated storm, sud-denly raising the temperature of Saturn’s stratosphere over 150 °F. Accompanying this enormous “burp” was a sudden increase in ethylene gas. It took Cassini’s Composite Infrared Spectrometer instrument to detect it. According to Dr. Scott Edgington, Deputy Project Scientist for Cassini, “Ethylene [C2H4] is normally present in only very low concentrations in Saturn’s atmosphere and has been very difficult to detect. Although it is a transitional product of the thermochemical proc-esses that normally occur in Saturn’s atmosphere, the concentrations detected concurrent with the big ‘burp’ were 100

times what we would expect.”

So what was going on?

Chemical reaction rates vary greatly with the energy available for the proc-ess. Saturn’s seasonal changes are exaggerated due to the effect of the rings acting as venetian blinds, throw-ing the northern hemisphere into shade during winter. So when the Sun again reaches the northern hemi-sphere, the photochemical reactions that take place in the atmosphere can speed up quickly. If not for its rings, Saturn’s seasons would vary as pre-dictably as Earth’s.

But there may be another cycle going on besides the seasonal one. Com-puter models are based on expected reaction rates for the temperatures and pressures in Saturn’s atmosphere, explains Edgington. However, it is very difficult to validate those models here on Earth. Setting up a lab to replicate conditions on Saturn is not easy!

Also contributing to the apparent mys-tery is the fact that haze on Saturn often obscures the view of storms be-

low. Only once in a while do storms punch through the hazes. Astronomers may have previously missed large storms, thus failing to notice any non-seasonal patterns. As for atmospheric events that are visible to Earth-bound telescopes, Edgington is particularly grateful for non-professional astronomers. While these astronomers are free to watch a planet continuously over long periods and record their finding in photographs, Cassini and its several science instruments must be shared with other scientists. Observation time on Cassini is planned more than six months in advance, making it diffi-cult to immediately train it on the unexpected. That’s where the volunteer astronomers come in, keeping a continuous watch on the changes taking place on Saturn. Edgington says, “Astronomy is one of those fields of study where amateurs can contribute as much as professionals.”

Go to http://saturn.jpl.nasa.gov/ to read about the latest Cassini discoveries. For kids, The space Place has lots of ways to explore Saturn at http://spaceplace.nasa.gov/search/cassini/.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

This false-colored Cassini image of Saturn was taken in near-infrared light on January 12, 2011. Red and orange show clouds deep in the atmosphere. Yellow and green are intermediate clouds. White and blue are high clouds and haze. The rings appear as a thin, blue horizontal line.

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New Free E-books Available about Two Famous NASA Space Telescopes NASA's Hubble Space Telescope has been providing astounding images of the universe since April 1990 and has led to remarkable discoveries. NASA's James Webb Space Telescope is the next-generation telescope that will peer even deeper into space and unveil even more mysteries. Both of these extraordinary telescopes are now the topics of two free e-books available from the Apple iBookstore.

The books are written on a high-school level and can be viewed using iPads with the free iBooks app. Because they're about two NASA space telescopes, the Hubble and its successor, the Webb, the books complement each other.

"These new e-books from NASA will allow people to discover Hub-ble and Webb in a whole new way — both the science and the tech-nology behind building them," said Amber Straughn, an astrophysi-cist on the Webb telescope pro-ject at NASA's Goddard Space Flight Center in Greenbelt, Md. "They collect all of the amazing resources about these two obser-vatories in an excellent product that I think people will really en-joy."

The e-books are highly interactive and include image galleries and videos. Tracy Vogel of the Space Telescope Science Institute in Baltimore, Md., is part of the de-sign team that put them together. "For instance, the readers can watch a galaxy collision simulation video, manipulate a telescope model to see it from all angles, or flip through a gallery of planetary nebulae — all right there on the page," Vogel said.

The book "Hubble Space Tele-scope: Discoveries" takes the reader on a tour of some of Hub-ble's most significant science suc-

cesses, combined with some of the telescope's technology and history. For more than two decades, Hubble has had a front-row seat for cosmic events: comets bombarding Jupiter, the explosive death of stars, the birth of new solar systems, and more. It helped reveal the age of the universe and stunned scientists with the discovery of the still-mysterious dark energy. The book details Hubble's work in cosmology, planetary science, and galactic science. Inter-active elements include a gallery of images taken by Hubble's different instruments, an interactive showing how as-tronomers measure distance in space, and a short movie on the discovery of planet Fomalhaut b.

In the e-book called the "James Webb Space Telescope: Science Guide," readers will learn how the Webb telescope will reveal in much more detail mysteries of the universe that the Hubble is not able to see. With a mirror almost seven times the area of the Hubble Space Telescope's, and an orbit far beyond Earth's moon, Hubble's successor will utilize infrared light to see the first galaxies being born in the very distant universe, penetrate clouds of dust to reveal newly forming stars and solar systems, and analyze planets around other stars for traces of potentially life-giving water. The Webb book explains the innovative technology and design making the Webb a reality. Among the interactive elements are images that transform as they're seen in different wavelengths of light, a simulation of the formation of the "cosmic web" in the early universe, a 3D fly-by interactive, and an animation of the Webb Telescope unfolding in space as it nears its orbit.

Information about how to download the books as well as a PDF version of the books is available at:

http://hubblesite.org/ibooks/

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Van Allen Probes reveal new dynamics of radiation belts

Just 96 days since their launch, NASA's twin Van Allen Probes have already provided new insights into the structure and behavior of the radiation belts that surround Earth, giving scientists a clearer understanding about the fundamental physical properties of these regions more than half a century after their discovery.

n a press conference on Tuesday, Dec. 4 at the American Geophysical Union's 2012 Fall Meeting in San Francisco, members of the Van Allen Probes science team discussed current findings made in unlocking the mys-teries of the radiation belts. These two donut-shaped regions of high-energy and hazardous particles -- named for their dis-coverer and the mission's namesake, Ameri-can physicist James Van Allen of the Univer-sity of Iowa -- are created by our planet's magnetosphere, and can harm space technologies such as satellites, as well as affect human space travel.

Throughout the brief early life of the two-year mission, energetic events and ejections of plasma from the sun caused dramatic changes in the radiation belts that, for the first time, were observed by twin spacecraft within the belts. "The sun has been a driver of these systems more than we had any right to expect," says Daniel Baker, Principal Investigator, Van Allen Probes Relativistic Electron Proton Telescope (REPT, which is part of the Energetic Particle, Composition, and Thermal Plasma Suite, or ECT), from the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder. "We're seeing brand new features we hadn't expected."

The twin probes, built and managed for NASA by the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., contain identical sets of five instrument suites. These suites have confirmed previous hypotheses about the belts' behavior, while also revealing that the belts are a far more dynamic and changing environment than previously thought. "We expected to see a fairly placid radiation belt system," Baker says. "Instead, we see that the belts have been extraordinarily active and dynamic during the first few weeks. We're looking in the right places at the right times."

Our planet's magnetosphere captures particles from the billions of tons of plasma ejected by the sun and from other sources; fields and waves of electricity and magnetism control and guide the charged particles within the belts, with the particles "surfing" on the waves, losing or gaining large amounts of energy along the way as they enter and leave the region. Measurements made by instruments like the Electric Fields and Waves Suite (EFW) and the Electric and Mag-netic Field Instrument Suite and Integrated Science (EMFISIS) are helping scientists understand how those fields and waves affect the particles. "The electric field and magnetic field measurements on the Van Allen Probes are the best ever made in the radiation belts," says the University of Iowa's Craig Kletzing, Principal Investigator for EMFISIS. "For the first time, we've been able to see how long intense low frequency electric fields and waves at the edge of the radia-tion belts can last -- sometimes for over five hours during geomagnetic storms. Before, it was like we could see a car zoom past, but not see anything about the details. Now, we can see what color the upholstery is."

The inner belt, where many satellites must operate, is home to the most hazardous and energized particles, mostly pro-tons. "A staggering number of the spacecraft we rely upon daily have to spend a part of their orbit in the harshest area of Earth's radiation environment," says Joseph Mazur of the Aerospace Corporation, Principal Investigator of the probes' Relativistic Proton Spectrometer (RPS). The Van Allen Probes are providing researchers with detailed views of how the populations of those particles vary with altitude, which should help engineers more effectively protect satellites. "This is the first time we've been able to measure the high energy particles in the heart of the radiation belts," Mazur said. "We're able to measure at the one billion electron volt level; particles at that energy are virtually impossible to shield against. They will easily penetrate half-inch thick aluminum plate." Particles at that energy level are known to cause a range of damages to spacecraft, from physical degradation to instrument malfunctions and false readings.

"NASA built these spacecraft to be super tough, and thank goodness we did," says APL's Nicky Fox, Van Allen Probes deputy project scientist. "The instruments are seeing the exact sorts of damaging effects we designed the spacecraft to survive."

The Van Allen Probes are part of NASA's Living With a Star Program to explore aspects of the connected sun-Earth system that directly affect life and society. LWS is managed by the agency's Goddard Space Flight Center in Greenbelt, Md. APL built the twin spacecraft and manages the mission for NASA.

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Shot Away from its Companion, Giant Star Makes Waves

The giant star Zeta Ophiuchi is having a "shocking" effect on the surrounding dust clouds in this infrared image from NA-SAs Spitzer Space Telescope. Stellar winds flowing out from this fast-moving star are making ripples in the dust as it ap-proaches, creating a bow shock seen as glowing gossamer threads, which, for this star, are only seen in infrared light.

Zeta Ophiuchi is a young, large and hot star located around 370 light-years away. It dwarfs our own sun in many ways -- it is about six times hotter, eight times wider, 20 times more massive, and about 80,000 times as bright. Even at its great distance, it would be one of the brightest stars in the sky were it not largely obscured by foreground dust clouds.

This massive star is travelling at a snappy pace of about 54,000 mph (24 kilometers per second), fast enough to break the sound barrier in the surrounding interstellar material. Because of this motion, it creates a spectacular bow shock ahead of its direction of travel (to the left). The structure is analogous to the ripples that precede the bow of a ship as it moves through the water, or the sonic boom of an airplane hitting supersonic speeds. The fine filaments of dust surrounding the star glow primarily at shorter infrared wavelengths, rendered here in green. The area of the shock pops out dramatically at longer infrared wavelengths, creating the red highlights.

A bright bow shock like this would normally be seen in visible light as well, but because it is hidden behind a curtain of dust, only the longer infrared wavelengths of light seen by Spitzer can reach us. Bow shocks are commonly seen when two different regions of gas and dust slam into one another. Zeta Ophiuchi, like other massive stars, generates a strong wind of hot gas particles flowing out from its surface. This expanding wind collides with the tenuous clouds of interstellar

gas and dust about half a light-year away from the star, which is almost 800 times the distance from the sun to Pluto. The speed of the winds added to the stars supersonic motion result in the spec-tacular collision seen here.

Our own sun has signifi-cantly weaker solar winds and is passing much more slowly through our galactic neighborhood so it may not have a bow shock at all. NASAs twin Voyager spacecraft are headed away from the solar system and are cur-rently about three times farther out than Pluto. They will likely pass be-yond the influence of the sun into interstellar space in the next few years, though this is a much gentler transition than that seen around Zeta Ophiu-chi.

For this Spitzer image, infrared light at wave-lengths of 3.6 and 4.5 microns is rendered in blue, 8.0 microns in green, and 24 microns in red.

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Little Telescope Spies Gigantic Galaxy Clusters WISE Press Release

Our solar system, with its colorful collection of planets, asteroids and comets, is a fleck in the grander cosmos. Hundreds of billions of solar systems are thought to reside in our Milky Way galaxy, which is itself just a drop in a sea of galaxies. The rarest and largest of galaxy groupings, called galaxy clusters, can be the hardest to find. That's where NASA's Wide-field Infrared Survey Explorer (WISE) can help. The mission's all-sky infrared maps have revealed one distant galaxy cluster and are expected to uncover thousands more. These massive structures are collections of up to thousands of galaxies bound together by gravity. They were born out of seeds of matter formed in the very early universe, and grew rapidly by a process called inflation. "One of the key questions in cosmology is how did the first bumps and wiggles in the distribution of matter in our uni-verse rapidly evolve into the massive structures of galaxies we see today," said Anthony Gonzalez of University of Flor-ida, Gainesville, who led the research program. The results are published in the Astrophysical Journal. "By uncovering the most massive of galaxy clusters billions of light-years away with WISE, we can test theories of the universe's early inflation period." WISE completed its all-sky survey in 2011, after surveying the entire sky twice at infrared wavelengths. The 16-inch (40-centimeter) telescope ran out of its coolant as expected in 2010, but went on to complete the second sky scan using two of its four infrared channels, which still functioned without coolant. At that time, the goal of the mission extension was to

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This galaxy cluster 7.7 billion light years away was discovered in data from the WISE Mission All Sky Survey. The discov-ery image is shown in the main panel. The inset shows a deeper optical and near-infrared composite image constructed using data form the WIYN telescope at Kitt Peak in Arizona and Subaru Telescope in Hawaii. The red galaxies in this image are part of the cluster, and the circles in this inset highlight the galaxies seen in WISE that were used to detect the cluster. This galaxy cluster is the first of thousands that are expected to be discovered with WISE over the entire sky.

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Hubble Sees a Galaxy Hit a Bull's-Eye Bright pink nebulae almost completely encircle a spiral galaxy in this NASA/ESA Hubble Space Telescope image of NGC 922. The ring structure and the galaxy’s distorted spiral shape result from a smaller galaxy scoring a cosmic bullseye, hitting the centre of NGC 922 some 330 million years ago.

In Hubble’s image, NGC 922 clearly reveals itself not to be a normal spiral galaxy. The spiral arms are disrupted, a stream of stars extends out towards the top of the image, and a bright ring of nebulae encircles the core. Observing with NASA’s Chandra X-ray Observatory reveals more chaos in the form of ultraluminous X-ray sources dotted around the galaxy.

NGC 922’s current unusual form is a result of a cosmic bullseye millions of years ago. A smaller galaxy, catalogued as 2MASXI J0224301-244443, plunged right through the heart of NGC 922 and shot out the other side. In wide-field views of the NGC 922, the small interloper can still be seen shooting away from the scene of the crash.

As the small galaxy passed through the middle of NGC 922, it set up ripples that disrupted the clouds of gas, and triggered the formation of new stars whose radiation then lit up the remain-ing gas. The bright pink color of the re-sulting nebulae is a characteristic sign of this process, and it is caused by excited hydrogen gas (the dominant element in interstellar gas clouds). This process

of excitation and emission of light by gases is similar to that in neon signs.

In theory, if two galaxies are aligned just right, with the small one passing through the centre of the larger one, the ring of nebulae should form a perfect circle, but more often the two galaxies are slightly off kilter, leading to a circle that, like this one, is noticeably brighter on one side than the other.

These objects, called collisional ring galaxies, are relatively rare in our cosmic neighborhood. Although galaxy colli-sions and mergers are commonplace, the precise alignment and ratio of sizes necessary to form a ring like this is not, and the ring-like phenomenon is also thought to be relatively short-lived.

The chances of seeing one of these galaxies nearby is therefore quite low. Despite the immense number of galax-ies in the Universe, this is one of only a handful known in our cosmic neighborhood (the Cartwheel Galaxy, being the most famous example). Observations of the more distant Universe (where we see further into the past) show that these rings were more common in the past, however.

Hubble’s image of NGC 922 consists of a series of exposures taken in visible light with Hubble’s Wide Field Cam-era 3, and in visible and near-infrared light with the Wide Field and Planetary Camera 2.

AAL Astronomy Associates of Lawrence

University of Kansas Malott Hall 1251 Wescoe Hall Dr, Room 1082 Lawrence, KS 66045-7582

Celestial Mechanic January 2013

hunt for more near-Earth asteroids via a project called NEOWISE. NASA has since funded the WISE team to combine all that data, allowing astronomers to study everything from nearby stars to distant galaxies. These next-generation all-sky images, part of a new project called "AllWISE," will be signifi-cantly more sensitive than those previously released, and will be publicly available in late 2013. Gonzalez and his team plan to use the enhanced WISE data to hunt for more massive galaxy clusters. The first one they spotted, MOO J2342.0+1301, is located more than 7 billion light-years away, or halfway back to the time of the Big Bang. It is hundreds of times more massive than our Milky Way. By scanning the whole sky with the improved AllWISE data, the team will sleuth out the true monsters of the bunch, clusters as big as thousands of times the mass of the Milky Way, assembled even earlier in the history of the universe. Galaxy clusters from the first half of the universe are hard to find because they are so far away and because not very many had time to assemble by then. What's more, they are especially hard to see using visible-light telescopes: light that left these faraway structures in visible wavelengths has been stretched into longer, infrared wavelengths due to the expansion of space. WISE can hunt some of these rare colossal structures down because it scanned the whole sky in infrared light. "I had pretty much written off using WISE to find distant galaxy clusters because we had to reduce the telescope di-ameter to only 16 inches [40 centimeters] to stay within our cost guidelines, so I am thrilled that we can find them after all," said Peter Eisenhardt, the WISE project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. and an author of the new paper. "The longer exposures from AllWISE open the door wide to see the most massive structures forming in the distant universe." Other projects planned for the enhanced WISE data include the search for nearby, hidden cool stars, including those with masses as low as planets. If a large planet or tiny star does exist close to our solar system, an object some call "Tyche," then WISE's infrared data may reveal it.

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