Monday, 21 October 2013

High above Saturn, new NASA image

A new iconic image from NASA?

High Above Saturn

This portrait looking down on Saturn and its rings was created from images obtained by NASA's Cassini spacecraft on Oct. 10, 2013. It was made by amateur image processor and Cassini fan Gordan Ugarkovic. This image has not been geometrically corrected for shifts in the spacecraft perspective and still has some camera artifacts.The mosaic was created from 12 image footprints with red, blue and green filters from Cassini's imaging science subsystem. Ugarkovic used full color sets for 11 of the footprints and red and blue images for one footprint.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit and
Image credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic 
Photonic Space

Sunday, 20 October 2013

UMass Amherst Social Psychologists Say War is Not Inevitable

Photonic Positive is back posting after a prolonged summer break: much to catch-up.

Here is an article from Massachusetts University Amherst with an optimistic view that questions the need for war and the role psychological science can play.

Peace Symbol on the  Lennon Wall in Prague, Czech Republic

 In a new review of how psychology research has illuminated the causes of war and violence, three political psychologists at the University of Massachusetts Amherst say this understanding can and should be used to promote peace and overturn the belief that violent conflict is inevitable.
Writing in the current special “peace psychology” issue of American Psychologist, lead author Bernhard Leidner, Linda Tropp and Brian Lickel of UMass Amherst’s Psychology of Peace and Violence program say that if social psychology research focuses only on how to soften the negative consequences of war and violence, “it would fall far short of its potential and value for society.”
“In summarizing psychological perspectives on the conditions and motivations that underlie violent conflict,” says Tropp, “we find that psychology’s contributions can extend beyond understanding the origins and nature of violence to promote nonviolence and peace.” She adds, “We oppose the view that war is inevitable and argue that understanding the psychological roots of conflict can increase the likelihood of avoiding violence as a way to resolve conflicts with others.”
Political leaders can be crucial in showing people different paths and alternatives to violent confrontation, the researchers point out. Leidner mentions Nelson Mandela, a leader who “offered South Africans an example of how to deal with the legacy of apartheid without resorting to further violence by making statements such as, ‘If you want to make peace with your enemy, you have to work with your enemy. Then he becomes your partner.’”
Leidner and colleagues recall how political and social psychology researchers have in recent decades steadily gained more understanding, through research, of such psychological factors as intergroup threat, uncertainty, group identity, emotions, moral beliefs and how intergroup conflict affects views of the world and of oneself.
They review theory and research that specify psychological factors that contribute to and perpetuate intergroup violence through emotional responses and belief systems fostered by conflict. Finally, they summarize ideas of how psychological “defenses of peace” –– a phrase in the United Nations Educational, Scientific and Cultural Organization (UNESCO) preamble –– can be constructed in the human mind.
The authors acknowledge that conflict and violence between groups persist because they often give people ways to address psychological needs, for identity, safety, security and power. Nonviolence has received far less media and research attention, they point out, but this should change. The UMass Amherst team urges social psychologists to consider factors that increase empathy and understanding of others, along with factors that increase the capacity for critical evaluation of the “ingroup.”
They conclude, “Research that investigates how to mitigate negative consequences of war and violence is valuable,” and the studies they summarize, grounded in “realistic insights,” support the view that psychology can be applied to promote peace. “It is our contention that psychology can and should be applied to promote peace, not war.”
The UMass Amherst Psychology of Peace and Violence Programwas launched in 2004 by a private endowment with matching university support. The only program of its kind in the United States, it uses scientific knowledge to resolve conflict between groups, promote reconciliation and build peace through cooperation. Faculty and students join a wide range of academic and community partners to decrease violence and promote peace through the application of research findings to real-world situations. The program hosts an international speakers series to bring peace and nonviolence research to the campus and local community.


Photonic Progress

Wednesday, 3 July 2013

Big Brother to the Milky Way

This image from NASA's Galaxy Evolution Explorer shows NGC 6744, one of the galaxies most similar to our Milky Way in the local universe. This ultraviolet view highlights the vast extent of the fluffy spiral arms, and demonstrates that star formation can occur in the outer regions of galaxies. The galaxy is situated in the constellation of Pavo at a distance of about 30 million light-years. NGC 6744 is bigger than the Milky Way, with a disk stretching 175,000 light-years across. A small, distorted companion galaxy is located nearby, which is similar to our galaxy's Large Magellanic Cloud. This companion, called NGC 6744A, can be seen as a blob in the main galaxy's outer arm, at upper right. On June 28, 2013, NASA turned off its Galaxy Evolution Explorer (GALEX) after a decade of operations in which the venerable space telescope used its ultraviolet vision to study hundreds of millions of galaxies across 10 billion years of cosmic time. Highlights from the mission's decade of sky scans include: -- Discovering a gargantuan, comet-like tail behind a speeding star called Mira. -- Catching a black hole "red-handed" as it munched on a star. -- Finding giant rings of new stars around old, dead galaxies. -- Independently confirming the nature of dark energy. -- Discovering a missing link in galaxy evolution -- the teenage galaxies transitioning from young to old. The mission also captured a dazzling collection of snapshots, showing everything from ghostly nebulas to a spiral galaxy with huge, spidery arms.  

Photonic Space

Saturday, 29 June 2013

Search for Habitable Moons around Kepler-22b

Judith E. Braffman-Miller speculates in her recent blog about moons on Exoplanets and the search for habitable environments near Kepler-22b.
image from NASA
Moons are enchanting, mesmerizing objects dwelling in their orbits around planets both within and beyond our Solar System. Earth's own large Moon, a silver-golden world that shines in our starlit night sky with the reflected fires of our Star, the Sun, has long been the inspiration of haunting poems and tales of love, as well as myths of magic and madness. Most of the moons of our Sun's own bewitching family are glistening little icy worlds in orbit around the giant planets of the outer Solar System. In June 2013, astronomers announced their dedicated hunt for a habitable moon-world beyond our Sun's family, circling around the planet Kepler-22b, that dwells in the faraway family of a different star.
Moons can be found in a rich assortment of various sizes, shapes, and types. Although they are generally solid little worlds, a few of them are known to sport atmospheres. Indeed, the atmosphere of the second largest moon in our Solar System, Titan of Saturn, is so dense that it hides Titan's strange hydrocarbon-slashed surface beneath a thick orange veil.
Most of the moons dwelling in our Sun's family were probably born from primordial disks of dust and gas, orbiting around newly formed planets, when our Solar System was very young about 4.5 billion years ago. There are at least 150 moons circling the planets in our Solar System--and about 25 moons are currently awaiting official confirmation of their discovery.
Of the four terrestrial, rocky planets of the inner Solar System (Mercury, Venus, our Earth, and Mars), both Mercury and Venus are moonless. Earth possesses one lone Moon, but it is a very large one--the fifth largest moon in our entire Solar System, in fact. Mars, on the other hand, has two tiny misshapen moons that resemble rocky potatoes, and are lumpy and dark, as they travel in their nearly circular orbits close to the plane of the Martian equator. The Martian moons, Phobos and Deimos, are probably asteroids that were captured by Mars long ago.
The outer Solar System is more richly endowed with moons than the inner regions. The two enormous gas giant planets, Jupiter and Saturn, and the ice giant planets, Uranus and Neptune, have numerous moons of various sizes, shapes, and origins. As these enormous planets grew, during the early days of our Solar System, they were able to ensnare wandering objects with their mighty gravitational grips.
Jupiter, the largest planet in our Solar System, also has the largest moon--Ganymede. A large number of Jovian moons sport highly elliptical orbits and also circle backwards--that is, opposite to the spin of their planet. Saturn, Uranus, and Neptune also sport such so-called irregular moons, that orbit far from their respective parent planets.
Earth's bewitching large Moon was probably born as the result of an immense impact, when a Mars-size protoplanet named Theia smashed into Earth about 4.5 billion years ago. This cataclysmic collision is thought to have hurled a vast amount of Earth-stuff and Theia-stuff into orbit around our ancient planet. Debris from the two unfortunate bodies gradually accumulated to give birth to our Moon, as tumbling little newborn moonlets crashed into one another and melded together into one large object.
We have known since 1995 that our Solar System is far from unique in the Cosmic scheme of things, and that there are a vast number of planets that circle stars beyond our own Sun. Furthermore, some of these extrasolar planets probably have moons just like most of the planets in our Sun's family. These faraway exomoons are enticing little worlds of wonder and mystery--and possibly even life.
A Habitable Exomoon For Kepler-22b?
Kepler-22b is an extrasolar planet that circles Kepler-22, a G-type star that is situated about 600 light-years from our own planet in the constellation Cygnus. This intriguing new world, that resides beyond our Solar System, was first spotted by NASA's highly productive, though ill-fated, Kepler Space Telescope in 2011. Kepler-22b has the distinction of being the first known transiting extrasolar planet to reside within the so-calledhabitable zone of its star. The habitable zone is the term used to describe that Goldilocks region around a star where water can exist in its life-loving liquid state. Planets dwelling in this fortunate region are not too hot, not too cold, but just right for water and, hence, life to exist. A planet that circles its star in the habitable zone suggests that there is the possibility--though not the promise--of life as we know it to exist on that world.
Kepler-22b's initial transit in front of the face of its fiery star was seen by Kepler on its third day of scientific observations, back in May 2009. The third passage was spotted in late 2010. Still more confirming evidence was provided by the infrared Spitzer Space Telescope, as well as by ground-based 'scopes. The confirmation of the existence of this interesting extrasolar planet world was announced on December 5, 2011.
Kepler-22b sports an orbital period of approximately 200 days. Its inclination is about 90 degrees, and it transits in front of the face of its star as observed by Earth-based astronomers. The shape of Kepler-22b's orbit is unknown, but it is known that its average orbital distance is well within its parent star's habitable zone. Many extrasolar planets are known to sport highly elliptical (football-shaped) orbits, and if Kepler-22b also travels along such a path around its star, it would only spend a tiny fraction of its time within this Goldilocks zone. This would cause the planet to undergo such extreme variations in temperature that it would not be a pleasant place for delicate living things to evolve and flourish. Kepler-22b is approximately 2.4 times the radius of Earth.
With the discoveries of 132 confirmed extrasolar planets and more than three thousand planet candidates, the Kepler mission revolutionized scientific understanding of planets residing beyond our own Star. Much of the attention surrounding these discoveries has focused on identifying an Earth-analog--a planet about the size of our own world dwelling within the precious Goldilocks zone around its distant star. Now, for the first time, Dr. David M. Kipping of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, and his team, have started to hunt for a habitable moon around Kepler-22b!
Kepler-22b, with its radius almost two and a half times that of Earth, is too large to be considered a true Earth-analog. Nevertheless, if it possesses an Earth-sized moon, the planetary system could still host a habitable world like our own.
In order to spot such a remote exomoon, the authors of this new study, The Hunt for Exomoons with Kepler (HEK): III. The First Search for an Exomoon around a Habitable-Zone Planet, used a technique that models the dips and features of the parent star's light-curve (stellar brightness vs. time), which are caused by transits of the planet (and any accompanying moons) in front of the face of its star. This is a complicated and difficult endeavor because numerous and diverse models of planet-moon dynamics must be taken into consideration. Each one of these models possesses parameters that describe physical properties belonging to the planet or moon, as well as parameters describing the orbital system. The authors use what is termed Bayesian statistics to account for the fact that the true orbital model of this planetary system is still not known--and this enables them to calculate if a model with our without a moon fits the observed light-curve the best.
The team also considered whether it would be possible to determine, with an adequate degree of certainty, if a detected moon could bear life-loving liquid water. In their analysis, the "input" climate for the moon is habitable, which is identified with high probability. However, there still remains approximately a one in six failure rate.
With such intriguing results before them, the team of astronomers studied the data to determine if Kepler-22b actually has a moon. Unfortunately, their analysis reveals no evidence for the existence of an exomoon circling Kepler-22b. This non-detection suggests that the mass of any companion world around Kepler-22b must be less than 0.54 times the mass of our planet--with an impressive confidence rate of 95%! Therefore, it is very unlikely that Kepler-22b is circled by an Earth-like moon. Nevertheless, it is still too soon to give up hope. The Hunt for Exomoons with Kepler project has studied nine planetary systems in search of exomoons. Although none were detected, with the team's new results about the possibility of finding Earth-sized moons and the remaining treasure trove of Kepler data to sift through, large and possibly even habitable exomoons may start being spotted in the near future.
Judith E. Braffman-Miller is a writer and astronomer whose articles have been published since 1981 in various newspapers, magazines, and journals. Although she has written on a variety of topics, she particularly loves writing about astronomy because it gives her the opportunity to communicate to others the many wonders of her field. Her first book, "Wisps, Ashes, and Smoke," will be published soon.

Photonic Progress

Imagination can change what we hear and see: spooky?

It appears what you see or hear isn't always what you get!  I wonder if this contributes more widely to 'spooky' experiences.
A study from the Swedish Karolinska Institutet shows, that our imagination may affect how we experience the world more than we perhaps think. What we imagine hearing or seeing 'in our head' can change our actual perception. The study, which is published in the scientific journal Current Biology, sheds new light on a classic question in psychology and neuroscience - about how our brains combine information from the different senses.
Henrik Ehrsson and Christopher Berger. Photo: Stefan Zimmerman
"We often think about the things we imagine and the things we perceive as being clearly dissociable," says Christopher Berger, doctoral student at the Department of Neuroscience and lead author of the study. "However, what this study shows is that our imagination of a sound or a shape changes how we perceive the world around us in the same way actually hearing that sound or seeing that shape does. Specifically, we found that what we imagine hearing can change what we actually see, and what we imagine seeing can change what we actually hear."
The study consists of a series of experiments that make use of illusions in which sensory information from one sense changes or distorts one's perception of another sense. Ninety-six healthy volunteers participated in total. In the first experiment, participants experienced the illusion that two passing objects collided rather than passed by one-another when they imagined a sound at the moment the two objects met. In a second experiment, the participants' spatial perception of a sound was biased towards a location where they imagined seeing the brief appearance of a white circle. In the third experiment, the participants' perception of what a person was saying was changed by their imagination of a particular sound.
Illusion of colliding objects.
According to the scientists, the results of the current study may be useful in understanding the mechanisms by which the brain fails to distinguish between thought and reality in certain psychiatric disorders such as schizophrenia. Another area of use could be research on brain computer interfaces, where paralyzed individuals' imagination is used to control virtual and artificial devices.
"This is the first set of experiments to definitively establish that the sensory signals generated by one's imagination are strong enough to change one's real-world perception of a different sensory modality", says Professor Henrik Ehrsson, the principle investigator behind the study.
This study was funded by the European Research Council, the Swedish Foundation for Strategic Research, the James S. McDonnell Foundation, the Swedish Research Council, and the Söderberg Foundation.
Photonic Progress

Friday, 28 June 2013

NASA's Voyager 1 Explores Final Frontier

Data from Voyager 1, now more than 11 billion miles (18 billion kilometers) from the sun, suggest the spacecraft is closer to becoming the first human-made object to reach interstellar space.

Research using Voyager 1 data and published in the journal Science today provides new detail on the last region the spacecraft will cross before it leaves the heliosphere, or the bubble around our sun, and enters interstellar space. Three papers describe how Voyager 1's entry into a region called the magnetic highway resulted in simultaneous observations of the highest rate so far of charged particles from outside heliosphere and the disappearance of charged particles from inside the heliosphere.
Scientists have seen two of the three signs of interstellar arrival they expected to see: charged particles disappearing as they zoom out along the solar magnetic field, and cosmic rays from far outside zooming in. Scientists have not yet seen the third sign, an abrupt change in the direction of the magnetic field, which would indicate the presence of the interstellar magnetic field.
"This strange, last region before interstellar space is coming into focus, thanks to Voyager 1, humankind's most distant scout," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. "If you looked at the cosmic ray and energetic particle data in isolation, you might think Voyager had reached interstellar space, but the team feels Voyager 1 has not yet gotten there because we are still within the domain of the sun's magnetic field."
Scientists do not know exactly how far Voyager 1 has to go to reach interstellar space. They estimate it could take several more months, or even years, to get there. The heliosphere extends at least 8 billion miles (13 billion kilometers) beyond all the planets in our solar system. It is dominated by the sun's magnetic field and an ionized wind expanding outward from the sun. Outside the heliosphere, interstellar space is filled with matter from other stars and the magnetic field present in the nearby region of the Milky Way.
Voyager 1 and its twin spacecraft, Voyager 2, were launched in 1977. They toured Jupiter, Saturn, Uranus and Neptune before embarking on their interstellar mission in 1990. They now aim to leave the heliosphere. Measuring the size of the heliosphere is part of the Voyagers' mission.
The Science papers focus on observations made from May to September 2012 by Voyager 1's cosmic ray, low-energy charged particle and magnetometer instruments, with some additional charged particle data obtained through April of this year.
Voyager 2 is about 9 billion miles (15 billion kilometers) from the sun and still inside the heliosphere. Voyager 1 was about 11 billion miles (18 billion kilometers) from the sun Aug. 25 when it reached the magnetic highway, also known as the depletion region, and a connection to interstellar space. This region allows charged particles to travel into and out of the heliosphere along a smooth magnetic field line, instead of bouncing around in all directions as if trapped on local roads. For the first time in this region, scientists could detect low-energy cosmic rays that originate from dying stars.
"We saw a dramatic and rapid disappearance of the solar-originating particles. They decreased in intensity by more than 1,000 times, as if there was a huge vacuum pump at the entrance ramp onto the magnetic highway," said Stamatios Krimigis, the low-energy charged particle instrument's principal investigator at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "We have never witnessed such a decrease before, except when Voyager 1 exited the giant magnetosphere of Jupiter, some 34 years ago."
Other charged particle behavior observed by Voyager 1 also indicates the spacecraft still is in a region of transition to the interstellar medium. While crossing into the new region, the charged particles originating from the heliosphere that decreased most quickly were those shooting straightest along solar magnetic field lines. Particles moving perpendicular to the magnetic field did not decrease as quickly. However, cosmic rays moving along the field lines in the magnetic highway region were somewhat more populous than those moving perpendicular to the field. In interstellar space, the direction of the moving charged particles is not expected to matter.
In the span of about 24 hours, the magnetic field originating from the sun also began piling up, like cars backed up on a freeway exit ramp. But scientists were able to quantify that the magnetic field barely changed direction -- by no more than 2 degrees.
"A day made such a difference in this region with the magnetic field suddenly doubling and becoming extraordinarily smooth," said Leonard Burlaga, the lead author of one of the papers, and based at NASA's Goddard Space Flight Center in Greenbelt, Md. "But since there was no significant change in the magnetic field direction, we're still observing the field lines originating at the sun."
NASA's Jet Propulsion Laboratory, in Pasadena, Calif., built and operates the Voyager spacecraft. California Institute of Technology in Pasadena manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.

For more information about the Voyager spacecraft mission, visit: and .


Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.

Steve Cole 202-358-0918
NASA Headquarters, Washington 

Photonic Space

Tuesday, 18 June 2013

Cassini Probe to Take Photo of Earth From Deep Space

NASA's Cassini spacecraft, now exploring Saturn, will take a picture of our home planet from a distance of hundreds of millions of miles on July 19. NASA is inviting the public to help acknowledge the historic interplanetary portrait as it is being taken. 

This simulated view from NASA's Cassini spacecraft shows the expected positions of Saturn and Earth on July 19, 2013, around the time Cassini will take Earth's picture. Cassini will be about 898 million miles (1.44 billion kilometers) away from Earth at the time. That distance is nearly 10 times the distance from the sun to Earth. Image credit: NASA/JPL-Caltech 

Earth will appear as a small, pale blue dot between the rings of Saturn in the image, which will be part of a mosaic, or multi-image portrait, of the Saturn system Cassini is composing.

"While Earth will be only about a pixel in size from Cassini's vantage point 898 million [1.44 billion kilometers] away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We hope you'll join us in waving at Saturn from Earth, so we can commemorate this special opportunity."

Cassini will start obtaining the Earth part of the mosaic at 2:27 p.m. PDT (5:27 p.m. EDT or 21:27 UTC) and end about 15 minutes later, all while Saturn is eclipsing the sun from Cassini's point of view. The spacecraft's unique vantage point in Saturn's shadow will provide a special scientific opportunity to look at the planet's rings. At the time of the photo, North America and part of the Atlantic Ocean will be in sunlight.

Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini's highest-resolution camera. The probe's position will allow it to turn its cameras in the direction of the sun, where Earth will be, without damaging the spacecraft's sensitive detectors.

"Ever since we caught sight of the Earth among the rings of Saturn in September 2006 in a mosaic that has become one of Cassini's most beloved images, I have wanted to do it all over again, only better," said Carolyn Porco, Cassini imaging team lead at the Space Science Institute in Boulder, Colo. "This time, I wanted to turn the entire event into an opportunity for everyone around the globe to savor the uniqueness of our planet and the preciousness of the life on it."

Porco and her imaging team associates examined Cassini's planned flight path for the remainder of its Saturn mission in search of a time when Earth would not be obstructed by Saturn or its rings. Working with other Cassini team members, they found the July 19 opportunity would permit the spacecraft to spend time in Saturn's shadow to duplicate the views from earlier in the mission to collect both visible and infrared imagery of the planet and its ring system.

"Looking back towards the sun through the rings highlights the tiniest of ring particles, whose width is comparable to the thickness of hair and which are difficult to see from ground-based telescopes," said Matt Hedman, a Cassini science team member based at Cornell University in Ithaca, N.Y., and a member of the rings working group. "We're particularly interested in seeing the structures within Saturn's dusty E ring, which is sculpted by the activity of the geysers on the moon Enceladus, Saturn's magnetic field and even solar radiation pressure."

This latest image will continue a NASA legacy of space-based images of our fragile home, including the 1968 "Earthrise" image taken by the Apollo 8 moon mission from about 240,000 miles (380,000 kilometers) away and the 1990 "Pale Blue Dot" image taken by Voyager 1 from about 4 billion miles (6 billion kilometers) away.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington, and designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team consists of scientists from the United States, the United Kingdom, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

To learn more about the public outreach activities associated with the taking of the image, visit: .

For more information about Cassini, visit and .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.

Dwayne Brown 202-358-1726
NASA Headquarters, Washington 
Photonic Space

Friday, 24 May 2013

Double Rainbow

Photonic Image

Here is an image of a spectacular double rainbow seen recently over my home in Sussex, England. I just grabbed the camera! It goes to show you don't need to be in space or have sophisticated equipment to capture arial phenomena (though of course it may help!): Steve

another image of the rainbow is here

Photonic Image

Spiral Galaxy M109

new NASA image

Beautiful barred spiral galaxy M109, 109th entry in Charles Messier's famous catalog of bright Nebulae and Star Clusters, is found just below the Big Dipper's bowl in the northern constellation Ursa Major. In telescopic views, its striking central bar gives the galaxy the appearance of the Greek letter "theta", θ, a common mathematical symbol representing an angle. Of course M109 spans a very small angle in planet Earth's sky, about 7 arcminutes or 0.12 degrees. But that small angle corresponds to an enormous 120,000 light-year diameter at the galaxy's estimated 60 million light-year distance. The brightest member of the now recognized Ursa Major galaxy cluster, M109 (aka NGC 3992) is joined by three spiky foreground stars strung out across this frame. The three small, fuzzy bluish galaxies also on the scene, identified left to right as UGC 6969, UGC 6940 and UGC 6923, are possibly satellite galaxies of the larger M109.

Photonic Space

Sunday, 12 May 2013

Scientists confirm that the Justinianic Plague was caused by the bacterium Yersinia pestis

DNA evidence from Johannes Gutenberg University, Mainz shed light on a plague that ravaged Europe in the 6th to 8th centuries AD and confirm it was caused by the same bacterium as the Black Death of the middle ages. here is their report. This settles a debate whether the various plagues had the same causative agent, that has raged for many years.

From the several pandemics generally called 'pestilences' three are historically recognized as due to plague, but only for the third pandemic of the 19th-21st centuries AD there were microbiological evidences that the causing agent was the bacterium Yersinia pestis. "For a long time scholars from different disciplines have intensively discussed about the actual etiological agents of the past pandemics. Only ancient DNA analyses carried out on skeletal remains of plague victims could finally conclude the debate", said Dr. Barbara Bramanti of the Palaeogenetics Group at the Institute of Anthropology at Johannes Gutenberg University Mainz (JGU). About two years ago, she headed the international team which demonstrated beyond any doubt that Y. pestis also caused the second pandemic of the 14th-17th centuries including the Black Death, the infamous epidemic that ravaged Europe from 1346-1351. Bramanti and her Mainz colleague Stephanie Hänsch now cooperated with the University of Munich, the German Bundeswehr, and international scholars to solve the debate as to whether Y. pestis caused the so-called Justinianic Plague of the 6th-8th centuries AD. The results of ancient DNA analyses carried out on the early medieval cemetery of Aschheim in Bavaria were published last week in PloS Pathogens. They confirmed unambiguously that Y. pestis was indeed the causing agent of the first pandemic, in contrast to what has been postulated by other scientists recently. This revolutionary result is supported by the analysis of the genotype of the ancient strain which provide information about the phylogeny and the place of origin of this plague. As for the second and third pandemic, the original sources of the plague bacillus were in Asia.

"It remains questionable whether at the time of the Byzantine Emperor Justinian only one strain or more were disseminated in Europe, as it was at the time of the Black Death," suggested Bramanti and Hänsch. To further investigate this and other open questions about the modalities and route of transmission of the medieval plagues, Bramanti has recently obtained an ERC Advanced Grant for the project "The medieval plagues: ecology, transmission modalities and routes of the infection" (MedPlag) and will move to the Center for Ecological and Evolutionary Synthesis (CEES) at the University of Oslo in Norway. The CEES, chaired by Nils Chr. Stenseth, has an outstanding and rewarded record of excellence in the research on infectious diseases and in particular on Y. pestis.
Photonic Progress

Friday, 10 May 2013

Secret Streets of Britain’s Atlantis are Revealed

A University of Southampton professor has carried out the most detailed analysis ever of the archaeological remains of the lost medieval town of Dunwich, dubbed ‘Britain’s Atlantis’.

Funded and supported by English Heritage, and using advanced underwater imaging techniques, the project led by Professor David Sear of Geography and Environment has produced the most accurate map to date of the town’s streets, boundaries and major buildings, and revealed new ruins on the seabed. Professor Sear worked with a team from the University’s GeoData Institute; the National Oceanography Centre, Southampton; Wessex Archaeology; and local divers from North Sea Recovery and Learn Scuba.

He comments, “Visibility under the water at Dunwich is very poor due to the muddy water. This has limited the exploration of the site.

“We have now dived on the site using high resolution DIDSON ™ acoustic imaging to examine the ruins on the seabed – a first use of this technology for non-wreck marine archaeology.

“DIDSON technology is rather like shining a torch onto the seabed, only using sound instead of light. The data produced helps us to not only see the ruins, but also understand more about how they interact with the tidal currents and sea bed.”

Peter Murphy, English Heritage’s coastal survey expert who is currently completing a national assessment of coastal heritage assets in England, says: “The loss of most of the medieval town of Dunwich over the last few hundred years – one of the most important English ports in the Middle Ages – is part of a long process that is likely to result in more losses in the future. Everyone was surprised, though, by how much of the eroded town still survives under the sea and is identifiable.

“Whilst we cannot stop the forces of nature, we can ensure what is significant is recorded and our knowledge and memory of a place doesn’t get lost forever. Professor Sear and his team have developed techniques that will be valuable to understanding submerged and eroded terrestrial sites elsewhere.”

Present day Dunwich is a village 14 miles south of Lowestoft in Suffolk, but it was once a thriving port – similar in size to 14th Century London. Extreme storms forced coastal erosion and flooding that have almost completely wiped out this once prosperous town over the past seven centuries. This process began in 1286 when a huge storm swept much of the settlement into the sea and silted up the Dunwich River. This storm was followed by a succession of others that silted up the harbour and squeezed the economic life out of the town, leading to its eventual demise as a major international port in the 15th Century. It now lies collapsed and in ruins in a watery grave, three to 10 metres below the surface of the sea, just off the present coastline.

The project to survey the underwater ruins of Dunwich, the world’s largest medieval underwater town site, began in 2008. Six additional ruins on the seabed and 74 potential archaeological sites on the seafloor have since been found. Combining all known archaeological data from the site, together with old charts and navigation guides to the coast, it has also led to the production of the most accurate and detailed map of the street layout and position of buildings, including the town’s eight churches. Findings highlights are:

* Identification of the limits of the town, which reveal it was a substantial urban centre occupying approximately 1.8 km2 – almost as large as the City of London
* Confirmation the town had a central area enclosed by a defensive, possibly Saxon earthwork, about 1km2
* The documentation of ten buildings of medieval Dunwich, within this enclosed area, including the location and probable ruins of Blackfriars Friary, St Peter’s, All Saint’s and St Nicholas Churches, and the Chapel of St Katherine
* Additional ruins which initial interpretation suggests are part of a large house, possibly the town hall
* Further evidence that suggests the northern area of the town was largely commercial, with wooden structures associated with the port
* The use of shoreline change analysis to predict where the coastline was located at the height of the town’s prosperity

Commenting on the significance of Dunwich, Professor Sear says: “It is a sobering example of the relentless force of nature on our island coastline. It starkly demonstrates how rapidly the coast can change, even when protected by its inhabitants.
“Global climate change has made coastal erosion a topical issue in the 21st Century, but Dunwich demonstrates that it has happened before. The severe storms of the 13th and 14th Centuries coincided with a period of climate change, turning the warmer medieval climatic optimum into what we call the Little Ice Age.
“Our coastlines have always been changing, and communities have struggled to live with this change. Dunwich reminds us that it is not only the big storms and their frequency – coming one after another, that drives erosion and flooding, but also the social and economic decisions communities make at the coast. In the end, with the harbour silting up, the town partly destroyed, and falling market incomes, many people simply gave up on Dunwich.”
Professor Sear’s full report can be found at:                  link to article
Photonic Progress