Posts by AltonParrish:
- Ancient Greece – Ancient Greeks did not view human sexuality the same as we do now. There seems to have been a lot more freedom. As women became land owners and their position in society increased, sexual freedoms became more acceptable as it was considered a gift from the Gods.
- The dawning of Christianity – There are scholars who have interpreted certain parts of the Scripture to indicate that some of the earliest Christians felt that because their sins were forgiven they had the freedom to commit all kinds of sexual immorality that had previously been denied them. The Apostle Paul addressed this issue several times in the Epistles admonishing early believers that they were to emulate Christ and abstain from sexual immorality and all other acts that were not in alignment with the teachings of Christ.
- Middle Ages – During the Middle Ages adultery was seen as a diversion for the upper classes. Men were expected to marry a virgin and marry well. However, before doing so, there was the expectation that they would have proven their virility on several occasions.
- Early U.S. History – At this time there were no divorces because there was no legal way for a couple to end their marriage. However in 1701, if you lived in Maryland, you were able to get a divorce. Divorces were only granted for adultery.
- Early 1900’s – Divorce rates were still relatively low, but higher for women than men, which would indicate a rise in adultery since that was the only reason one could get divorced.
- 1930’s – During the great depression divorce rates more than quadrupled for both men and women. Most likely the stress of the times caused an increase in adultery and the fact that during the 1920’s there was a much looser lifestyle on the rise than had been seen before.
- World War II – This period of time saw another spike in the divorce rate, presumably due to the many wartime marriages that took place where people did not really know each other that well. Many marriages were the result of young people feeling that they had to get married since the males were going off to war.
- 1950’s – This period of time saw the steady increase of divorce rates, over twice the rates of the Great Depression era. At this time divorce was still only granted on grounds of adultery.
- 1960’s and 70’s – During this time of history, society was going through some major changes. This was the era of “free love,” the Vietnam War was in full swing, Civil Rights and Women’s rights were also being fought for. Once again the divorce rate spiked, this time, it is thought that the advent of no fault divorce played a part in the spike. Even so, history tells us that sexual exploitation was rampant.
- 21st Century – Once again, society has gone through some serious changes. People are viewing marriage and relationships differently. Statistically it looks like adultery is still on the rise and the disillusionment of marriage and our disposable mentality seems to be at the root of it.
Particle Accelerator Discovered In The Heart Of Earth’s Radiation Belt
July 26th, 2013By Alton Parrish.
Recent observations by NASA’s twin Van Allen Probes show that particles in the radiation belts surrounding Earth are accelerated by a local kick of energy, helping to explain how these particles reach speeds of 99 percent the speed of light.
Image Credit: G. Reeves/M. Henderson
In order for scientists to understand the belts better, the Van Allen Probes were designed to fly straight through this intense area of space. When the mission launched in August 2012, it had top-level goals to understand how particles in the belts are accelerated to ultra-high energies, and how the particles can sometimes escape. By determining that this superfast acceleration comes from these local kicks of energy, as opposed to a more global process, scientists have been able to definitively answer one of those important questions for the first time.
“This is one of the most highly anticipated and exciting results from the Van Allen Probes,” said David Sibeck, Van Allen Probes project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “It goes to the heart of why we launched the mission.”
The radiation belts were discovered upon the launch of the very first successful U.S. satellites sent into space, Explorers I and III. It was quickly realized that the belts were some of the most hazardous environments a spacecraft can experience. Most satellite orbits are chosen to duck below the radiation belts or circle outside of them, and some satellites, such as GPS spacecraft, must operate between the two belts. When the belts swell due to incoming space weather, they can encompass these spacecraft, exposing them to dangerous radiation. Indeed, a significant number of permanent failures on spacecraft have been caused by radiation. With enough warning, we can protect technology from the worst consequences, but such warning can only be achieved if we truly understand the dynamics of what’s happening inside these mysterious belts.
“Until the 1990s, we thought that the Van Allen belts were pretty well-behaved and changed slowly,” said Geoff Reeves, the first author on the paper and a radiation belt scientist at Los Alamos National Laboratory in Los Alamos, N.M. “With more and more measurements, however, we realized how quickly and unpredictably the radiation belts changed. They are basically never in equilibrium, but in a constant state of change.”
In fact, scientists realized that the belts don’t even change consistently in response to what seem to be similar stimuli. Some solar storms caused the belts to intensify; others caused the belts to be depleted, and some seemed to have almost no effect at all. Such disparate effects from apparently similar events suggested that this region is much more mysterious than previously thought. To understand – and eventually predict – which solar storms will intensify the radiation belts, scientists want to know where the energy that accelerates the particles comes from.
The twin Van Allen Probes were designed to distinguish between two broad possibilities on what processes accelerate the particles to such amazing speeds: radial acceleration or local acceleration. In radial acceleration, particles are transported perpendicular to the magnetic fields that surround Earth, from areas of low magnetic strength far from Earth to areas of high magnetic strength nearer Earth. The laws of physics dictate that the particle speeds in this scenario will speed up when the magnetic field strength increases. So the speed would increase as the particles move toward Earth, much the way a rock rolling down hill gathers speed simply due to gravity. The local acceleration theory posits that the particles gain energy from a local energy source more similar to the way hot ocean water spawns a hurricane above it.
Two swaths of particles surrounding Earth called the radiation belts are one of the greatest natural accelerators in the solar system, able to push particles up to 99% the speed of light. The Van Allen Probes launched in August 2012, have now discovered mechanisms behind this acceleration.
Image Credit: NASA/Goddard /Scientific Visualization Studio
To help distinguish between these possibilities, the Van Allen Probes consist of two spacecraft. With two sets of observations, scientists can measure the particles and energy sources in two regions of space simultaneously, which is crucial to distinguish between causes that occur locally or come from far away. Also, each spacecraft is equipped with sensors to measure particle energy and position and determine pitch angle – that is, the angle of movement with respect to Earth’s magnetic fields. All of these will change in different ways depending on the forces acting on them, thus helping scientists distinguish between the theories.
Equipped with such data, Reeves and his team observed a rapid energy increase of high-energy electrons in the radiation belts on Oct. 9, 2012. If the acceleration of these electrons was occurring due to radial transport, one would measure effects starting first far from Earth and moving inward due to the very shape and strength of the surrounding fields. In such a scenario, particles moving across magnetic fields naturally jump from one to the next in a similar cascade, gathering speed and energy along the way – correlating to that scenario of rocks rolling down a hill.
But the observations didn’t show an intensification that formed further away from Earth and gradually moved inward. Instead they showed an increase in energy that started right in the middle of the radiation belts and gradually spread both inward and outward, implying a local acceleration source.
“In this particular case, all of the acceleration took place in about 12 hours,” said Reeves. “With previous measurements, a satellite might have only been able to fly through such an event once, and not get a chance to witness the changes actually happening. With the Van Allen Probes we have two satellites and so can observe how things change and where those changes start.”
Scientists believe these new results will lead to better predictions of the complex chain of events that intensify the radiation belts to levels that can disable satellites. While the work shows that the local energy comes from electromagnetic waves coursing through the belts, it is not known exactly which such waves might be the cause. During the set of observations described in the paper, the Van Allen Probes observed a specific kind of wave called chorus waves at the same time as the particles were accelerated, but more work must be done to determine cause and effect.
“This paper helps differentiate between two broad solutions,” said Sibeck. “This shows that the acceleration can happen locally. Now the scientists who study waves and magnetic fields will jump in to do their job, and find out what wave provided the push.”
Luckily, such a task will also be helped along by the Van Allen Probes, which were also carefully designed to measure and distinguish between the numerous types of electromagnetic waves.
“When scientists designed the mission and the instrumentation on the probes, they looked at the scientific unknowns and said, ‘This is a great chance to unlock some fundamental knowledge about how particles are accelerated,’” said Nicola J. Fox, deputy project scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “With five identical suites of instruments on board twin spacecraft – each with a broad range of particle and field and wave detection – we have the best platform ever created to better understand this critical region of space above Earth.”
The Applied Physics Laboratory built and operates the twin Van Allen Probes for NASA’s Science Mission Directorate. The Van Allen Probes comprise the second mission in NASA’s Living With a Star program, managed by Goddard, to explore aspects of the connected sun-Earth system that directly affect life and society.
For more information about the Van Allen probes, visit: www.nasa.gov/vanallenprobes/
Contacts and sources:
Karen C. Fox
NASA’s Goddard Space Flight Center
10 Historic Times That Saw A Rise In Adultery And Why
July 25th, 2013Contacts and sources:
A Blue Planet Like Earth Discovered
July 23rd, 2013
By Alton Parrish.
At a distance of 63 light-years from us, this turbulent alien world is one of the nearest exoplanets to Earth that can be seen crossing the face of its star. By observing this planet before, during, and after it disappeared behind its host star during orbit, astronomers were able to deduce that HD 189733b is a deep, azure blue — reminiscent of Earth’s color as seen from space.
Credit: NASA, ESA, M. Kornmesser
Credit: A. Fujii
“This planet has been studied well in the past, both by ourselves and other teams,” says Frédéric Pont of the University of Exeter, UK, leader of the Hubble observing programme and an author of this new paper. “But measuring its colour is a real first — we can actually imagine what this planet would look like if we were able to look at it directly.”
In order to measure what this planet would look like to our eyes, the astronomers measured how much light was reflected off the surface of HD 189733b — a property known as albedo [2].
Because the planet is only 63 light-years from Earth, a visitor would see many of the same stars we see in our nighttime sky, though the constellation patterns would be different. Our Sun and the nearest star to our Sun, Alpha Centauri, are labelled here – two faint stars near the centre of the image. Also labelled is Sirius, the brightest star in our skies in the constellation of Canis Major (The Greater Dog).
HD 189733b is faint and close to its star. To isolate the planet’s light from this starlight, the team used Hubble’s Space Telescope Imaging Spectrograph (STIS) to peer at the system before, during, and after the planet passed behind its host star as it orbited. As it slipped behind its star, the light reflected from the planet was temporarily blocked from view, and the amount of light observed from the system dropped. But this technique also shows how the light changes in other ways — for example, its colour [3].
“We saw the brightness of the whole system drop in the blue part of the spectrum when the planet passed behind its star,” explains Tom Evans of the University of Oxford, UK, first author of the paper. “From this, we can gather that the planet is blue, because the signal remained constant at the other colours we measured.”
The planet’s azure blue colour does not come from the reflection of a tropical ocean, but is due to a hazy, turbulent atmosphere thought to be laced with silicate particles, which scatter blue light [4]. Earlier observations using different methods have reported evidence for scattering of blue light on the planet, but these most recent Hubble observations give robust confirming evidence, say the researchers.
HD 189733b presented a favourable case for these kinds of measurements as it belongs to a class of planets known as “hot Jupiters”. These massive planets are similar in size to the gas giants in the Solar System, but instead lie very close to their parent star — this size and proximity to their star make them perfect subjects for exoplanet hunting. We know that hot Jupiters are numerous throughout the Universe. As we do not have one close to home in our own Solar System, studies of planets like HD 189733b are important to help us understand these dramatic objects.
“It’s difficult to know exactly what causes the colour of a planet’s atmosphere, even for planets in the Solar System,” says Pont [5]. “But these new observations add another piece to the puzzle over the nature and atmosphere of HD 189733b. We are slowly painting a more complete picture of this exotic planet.”
Notes
[1] In 2007 NASA’s Spitzer Space Telescope measured the infrared light from the planet, producing one of the first ever temperature maps for an exoplanet. The map shows that day- and night-side temperatures differ by about 260 degrees Celsius, causing fierce winds to roar across the planet. The condensation temperature of the silicates (over 1300 degrees Celsius) mean these particles could form very small grains of glass in the atmosphere.
[2] Albedo is a measure of how much incident radiation is reflected. The greater the albedo, the greater the amount of light reflected. This value ranges from 0 to 1, with 1 being perfect reflectivity and 0 being a completely black surface. The Earth has an albedo of around 0.4.
[3] This technique is possible because the planet’s orbit is tilted edge-on as viewed from Earth, so that it routinely passes in front of and behind the star. When the planet passes behind its host star, the light received from the system drops by about one part in 10 000.
[4] The deep blue colour of HD 189733b is consistent with the “red sunset of HD 189733b” result from the transit spectrum (heic0720). If sodium absorbs red light and dust scatters red light, the atmosphere will redden light shining through it, but will appear blue in reflected light.
[5] The colours of Jupiter and Venus are both due to unknown particles within the atmospheres of the planets. Earth looks blue from space because the oceans absorb red and green wavelengths more strongly than blue ones, and reflect the blueish hue of our sky. The shorter blue wavelengths of sunlight are selectively scattered by oxygen and nitrogen molecules in our atmosphere via a process called Rayleigh scattering.
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
The new paper, titled “The deep blue colour of HD 189733b: albedo measurements with HST/STIS at visible wavelengths”, will appear in the 1 August issue of the journal Astrophysical Journal Letters.
[1] The international team of astronomers in this study consists of T. Evans (University of Oxford, UK), F. Pont (University of Exeter, UK), D. K. Sing (University of Exeter, UK), S. Aigrain (University of Oxford, UK), J. K. Barstow (University of Oxford, UK), J-M. Désert (California Institute of Technology, USA; Sagan Postdoctoral Fellow), N. Gibson (European Southern Observatory, Germany), K. Heng (University of Bern, Switzerland), H. A. Knutson (California Institute of Technology, USA) and A. Lecavelier des Etangs (Universite Pierre et Marie Curie, France).
15 Female Journalists Who’ve Paved the Way
July 22nd, 2013By Alton Parrish.
- Nellie Bly: Elizabeth Jane Cochran, better known as Nellie Bly, famously endured one of the most courageous, brutal acts of undercover journalism ever. Ten Days in a Mad-House chronicled the squalid, abusive plight of the mentally ill interred in asylums — atrocities she witnessed firsthand after faking instability and landing in the women’s facilities on Blackwell’s Island. After publishing her discoveries in 1887, the United States government launched a formal investigation and subsequently called for significant mental healthcare reform. Even beyond that, Bly also reached out to other charitable and social causes, traveling the world and reporting back the politics and culture of all the peoples encountered.
- Marion Carpenter: Thanks to this photojournalist’s passion and drive, one of the industry’s glass ceilings received a nice little breaking. After launching her career with Washington Times-Herald in 1944, she joined International News Photo and worked on special assignments involving federal politicians. But her biggest contribution to women in journalism came when she became the first female member of the White House News Photographers Association. This honor bought Carpenter daily interaction with President Harry S. Truman, with whom she also traveled, and resulted in some famous portraits.
- Katie Couric: Broadcast journalist Katie Couric, known for her work with NBC and CBS, paved the way for others in her field when she became the first woman to solo anchor a weekday evening newscast. She began her stint with CBS Evening News in 2006, continuing to participate in specials on a wide variety of subjects. But today’s audiences know Couric for her political commentary and interviews with everyone from Sarah Palin to Shakira, though the majority of her more memorable ones involve current and former heads of state. And, of course, the 15 years she spent co-anchoring The Today Show with Tom Brokaw.
- Evelyn Cunningham: Pittsburgh Courier played a pivotal role in the Civil Rights Movement, with Evelyn Cunningham’s sterling, fearless efforts front and center. As both a correspondent and, later, the editor, she tackled social injustices — most especially lynching — the mainstream media never bothered touching. Cunningham also enjoyed the honor of profiling Civil Rights leaders such as Dr. Martin Luther King, Jr. and Malcolm X. Her absolutely amazing accomplishments, which also stretched into a radio career, earned her prestigious positions on several human rights organizations and even a special assistant gig with Nelson Rockefeller.
- Dorothy Dix: Love them, hate them or indifferent them, advice columns eventually became a permanent element of newspaper and magazine journalism. Elizabeth Meriwether Gilmer worked under the pseudonym Dorothy Dix and reached an audience of around 60 million in her prime. Dorothy Dix Talks began life in 1896, publishing marriage and homemaking advice on the pages of New Orleans periodicalDaily Picayune. After Public Ledger Syndicate picked it up in 1923, her readership expanded to 273 papers around the world, earning her a swath of dedicated fans and a few book deals — not to mention the honor of being the most widely-read female journalist during the era.
- Betty Friedan: Betty Friedan’s journalism background revolutionized women’s rights from both a rhetorical and professional standpoint. 1963’s The Feminine Mystique helped kick off Second Wave Feminism thanks to her painstaking investigative research delving deeply into the disturbing psychological realities of American housewives. Friedan herself had been previously fired from her journalist position at UE News for no reason other than pregnancy — an incident that ended up sparking a significant cultural shift. These firebrand actions paved the way for many, many more women than merely those in her industry.
- Margaret Fuller: As a voracious reader, it makes perfect sense that the vibrant Margaret Fuller would go on to become the first full-time, American, female book review journalist. Her transcendentalist leanings inspired good friend Ralph Waldo Emerson to offer her an editorship position with The Dial in 1839. From there, she joined up with New York Tribune and secured a lauded literary critic spot, though Fuller also covered the visual and performing arts, social justice and political issues on occasion. Two years after that, the newspaper named her its first female editor because of her column’s great success.
- Mary Garber: For nearly 70 years, heavily decorated Mary Garber enjoyed preeminence as the veritable First Lady of sports journalism. Her career launched in 1940 as Twin City Sentinel‘s society editor, but snapped up general assignments once World War II started leaving holes in the staff — and it just so happened that sports coverage needed a warm body after a while. After that, Geaber’s knowledge, passion and tenacity earned her a litany of awards, honors and critical acclaim. Most importantly of all, though, such a success challenged preconceived notions of women and journalism.
- Ayala Hasson-Nesher: This news correspondent with IBA is considered one of Israel’s foremost political commentators, earning the very first Queen of the Desert Award celebrating female empowerment. Ayala Hasson-Nesher’s career unearthed some incredibly shattering conspiracies, most notably the Bar-On-Hebron controversy of 1997. Today, she hosts the news magazine show Yoman on weekends and continues to cover the hard-hitting political stories garnering her initial renown. In addition to being seen on IBA, Israeli citizens can hear her “Hakol Diburim” radio program on its Kol Yisrael station.
- Marguerite Higgins: Female war correspondents today owe a debt of gratitude to Marguerite Higgins for her pioneering work in World War II, Korea and Vietnam. She launched such an illustrious pedigree with New York Herald Tribune, eventually covering such momentous historical events as the liberation of Dachau, the Nuremberg Trials and the first few days of the Korean War in addition to interviewing notable names like Jawaharlal Nehru, Francisco Franco and Nikita Khrushchev. General Douglas MacArthur declared the ban on female war correspondents because of Higgins’ tenacity as the Korean War broke out. Among her myriad other awards and accomplishments, this influential woman was the very first to ever receive a Pulitzer Prize.
- Nancy Hicks Maynard: The Maynard Institute of Journalism Education leaves a wonderful legacy for its stunning, groundbreaking co-founder. Nancy Hicks Maynard paved the way for women and minority journalists alike when she became the first African-American, female reporter with The New York Times, working on education, science and healthcare stories. After that, she served as president of the MIJE, which she co-founded with husband Robert C. Maynard. Together, they also purchased the struggling newspaper Oakland Tribune — thus making it the very first entirely African-American owned and operated daily in a major metropolitan area.
- Ethel L. Payne: In 1972, Ethel L. Payne made history when CBS made her the very first African-American female commentator at a major news organization. Her blend of journalism and activism during the Civil Rights Era garnered the nickname “First Lady of the Black Press,” and she started out covering the lives of black soldiers stationed in Japan. While working for the Chicago Defender, Payne stood at the forefront of racial equality, with stories about the 1963 March on Washington, the Montgomery Bus Boycott, desegregation of the University of Alabama and plenty more. She even famously interviewed President Dwight D. Eisenhower and asked him point blank about the desegregation of interstate transportation.
- Pearl Stewart: Oakland Tribune once again played an integral role in equitable journalism when it hired Pearl Stewart for its editor position. Though it only lasted seven months from 1992 to 1992, she still became the very first African-American woman to edit a major city’s newspaper. Over a decade after departing to make room for original chair holder David Burgin, Stewart took up editing for Chicago Defender, although she ended up resigning two months after. Most of her legacy goes largely unsung, however, as she served in several roles at Florida A&M’s School of Journalism and Graphic Communication.
- Barbara Walters: These days, most think of Barbara Walters as a celebrity first, journalist second, with many completely unaware of her earlier gender breakthroughs. In 1974, NBC named her the first female anchor on a major network’s evening news. Walters co-anchored The Today Show and, in doing so, opened up the floodgates for other women journalists wanting a spot on local and national programming. It probably comes as no shock to anyone, but she encountered considerable sexism from the men with whom she shared desk and studio space — and boy howdy will she remind everyone at any given opportunity.
- Oprah Winfrey: Oprah Winfrey, regardless of opinion, undoubtedly shapes a not-insignificant segment of pop culture with her juggernaut media empire. The very definition of a self-made billionaire, her traumatized, impoverished childhood ended when she landed a position anchoring the local news at age 19. From there, she climbed her way up the professional hierarchy — no easy feat for a minority woman — and completely revolutionized the daytime talk show format into something viable and (to tens of millions of viewers) relevant. Today, her worldwide acclaim and personal and financial successes inspire many female journalists hoping for even a molecule of what she’s earned.
Will Comet ISON Collide With Earth? Timeline Of Its Perilous Journey
July 22nd, 2013
By Alton Parrish.
For those who are familiar with the night sky, you already know the answer because you’ve already looked at the projected trajectory of ISON and read many blog posts about it. For you guys, I don’t think it comes as any surprise when I say the short answer to the question of ‘Will ISON hit us?’ is no.
But c’mon, don’t you want to know why?
A comet’s journey through the solar system is perilous and violent. A giant ejection of solar material from the sun could rip its tail off. Before it reaches Mars — at some 230 million miles away from the sun — the radiation of the sun begins to boil its water, the first step toward breaking apart. And, if it survives all this, the intense radiation and pressure as it flies near the surface of the sun could destroy it altogether.
Predicted hour-by-hour position of Comet ISON in various instruments on one of NASA’s Solar Terrestrial Relations Observatory spacecraft between 1 a.m. EST on Nov. 26, 2013, and 7 p.m. EST on Nov. 29, 2013. The blue field of view is from the outer coronagraph and green from the inner coronagraph.
Image Credit: NASA/STEREO/Goddard Space Flight CenterRight now, Comet ISON is making that journey. It began its trip from the Oort cloud region of our solar system and is now travelling toward the sun. The comet will reach its closest approach to the sun on Thanksgiving Day — Nov. 28, 2013 — skimming just 730,000 miles above the sun’s surface. If it comes around the sun without breaking up, the comet will be visible in the Northern Hemisphere with the naked eye, and from what we see now, ISON is predicted to be a particularly bright and beautiful comet.
Cataloged as C/2012 S1, Comet ISON was first spotted 585 million miles away in September 2012. This is its very first trip around the sun, which means it is still made of pristine matter from the earliest days of the solar system’s formation, its top layers never having been lost by a trip near the sun. Scientists will point as many ground-based observatories as they can and at least 15 space-based assets towards the comet along the way, in order to learn more about this time capsule from when the solar system first formed.
Even if the comet does not survive, tracking its journey will help scientists understand what the comet is made of, how it reacts to its environment, and what this explains about the origins of the solar system. Closer to the sun, watching how the comet and its tail interact with the vast solar atmosphere can teach scientists more about the sun itself.
Image Credit: NASA, ESA, J.-Y. Li (Planetary Science Institute)NASA has initiated a Comet ISON Observing Campaign to facilitate a massive global observation campaign incorporating both space-based and ground-based telescopes and encouraging citizen scientists and both professional and amateur astronomers to participate.
Read on for a timeline of observations expected of Comet ISON on its perilous journey.
10,000 years ago
The comet began its journey from the Oort cloud, a swath of icy objects that orbit far beyond Neptune. This is Comet ISON’s first trip through the inner solar system.
September 2012
Comet ISON was first discovered by Russian astronomers, Vitali Nevski and Artyom Novichonok, using the International Scientific Optical Network in Kislovodsk, Russia.
For two months, NASA’s Swift mission observed ISON when it was around 460 million miles away from the sun. (http://1.usa.gov/13E3yg0) Observations showed that ISON was shedding about 112,000 pounds of dust and 130 pounds of water every minute. The lower amount of water represents the fact that the comet was too far away from the sun for its water ice to have begun evaporating. Instead, other materials such as carbon dioxide or carbon monoxide ice were boiling off.
NASA’s Hubble Space Telescope observed Comet ISON at 386 million miles away from the sun on April 10, 2013. (http://1.usa.gov/ZGGitt) Preliminary Hubble observations provided surprising results: The nucleus of the comet appeared to be no larger than 3 to 4 miles across. Since the comet was so bright and so active, scientists had assumed the nucleus was larger. Hubble found the dusty coma, or head of the comet, to be around 3,100 miles across and the tail to be more than 57,000 miles long. HST also observed the comet on May 2 and May 7, and produced an upper limit on how fast the comet was producing carbon monoxide. Hubble also released a movie of the comet from May 8, 2013:http://1.usa.gov/17RuUS1
NASA’s Spitzer Space Telescope observed Comet ISON at 310 million miles away from the Sun. The data are still being processed and no results have been announced yet.
Sometime in late July or early August, the comet will pass what’s called the frost line, some 230 to 280 million miles away from the sun, when it will feel enough radiation from the sun that water will begin to evaporate and the comet will appear brighter. Some comets have broken up upon crossing the frost line.
Beginning in August, astronomers will be able to observe the comet through ground-based telescopes once again.From early June through late-August, ISON was almost directly behind the sun as viewed from Earth, and thus could not be observed from the ground.
In September, the comet will be visible near dawn in the Southern Hemisphere with binoculars.
Launch window for the Balloon Rapid Response for ISON, or BRRISON. This balloon, which with its payload will be 671 feet tall, taller than the Washington Monument, will launch from NASA’s Scientific Balloon Flight Facility in Fort Sumner, N.M. for a single day, carrying a 2.6-foot telescope and other science equipment. It will soar up to 23 miles above Earth’s surface, where it can observe the comet largely unhindered by Earth’s atmosphere.BRRISON will observe ISON in the near-infrared, near-ultraviolet and visible wavelength ranges, and will measure the ratio of carbon dioxide to water emissions from the comet. This ratio will be a vital diagnostic of the comet’s origins. These emissions are blocked by Earth’s atmosphere and cannot be measured from the ground.
BRRISON is an unprecedented quick-reaction project to take advantage of the opportunity presented by the discovery of comet ISON, and is the first NASA Planetary Science Division balloon mission to observe a comet.
Mars Curiosity and Opportunity will have a view of ISON in October, with Oct. 1, 2013, being the comet’s closest approach to Mars.Comet ISON will be close enough to the sun, as of Oct. 10 that it will be visible by an instrument with an extremely wide view on one of the solar observatories: the HI 2 instrument on one of NASA’s Solar Terrestrial Relations Observatories, STEREO-A. At that point the comet will be around 94.5 million miles away from the sun.
Additional Hubble observations are planned to provide new estimates on nucleus size and composition as well as to search for any fragments that have broken off.
November 2013
Observations of Comet ISON with NASA’s Chandra X-ray Observatory will be used to study particles streaming away from the sun in the solar wind. These particles from the sun interact with Comet ISON to generate X-rays that are detected by Chandra. The first of two sets of observations is planned for early November, when Comet ISON will be passing through the hot wind produced by regions along the sun’s equator.
Comet ISON will be visible to MESSENGER, which is near Mercury. The closest approach will be on Nov. 19.Once the comet passes Mercury, it will be on the most perilous part of its journey. The intense radiation of the sun causes material to evaporate quickly off the comet. Moreover the very pressure of the solar particles on the comet can cause it to break up. A slew of space and ground-based telescopes will watch the comet as it makes its slingshot around the sun.
Launch window for NASA’s FORTIS (short for Far-ultraviolet Off Rowland-Circle for Imaging and Spectroscopy) sounding rocket, which will measure ultraviolet light from Comet ISON as it nears the sun. Such light can help scientists determine the production rate of volatile chemicals leaving the comet surface and also can be used to search for previously undetected types of atoms or molecules on the comet.
As of Nov. 21, Comet ISON will begin to enter the fields of view of NASA’s space-based solar observatories. Comet ISON will be viewed first in what’s called coronagraphs, images that block the brighter view of the sun itself in order to focus on the solar atmosphere, the corona. Such images – from STEREO and the joint European Space Agency/NASA Solar Heliospheric Observatory, or SOHO — will likely be quite visually compelling. NASA’s Solar Dynamics Observatory, or SDO, will view the comet for a few hours around perihelion. SDO’s imagery should be detailed enough to gather information about how the comet evolves through the radiation and pressure of the sun’s atmosphere.All of these observatories will have different views. STEREO-A will be the only one that sees the comet transit across the face of the sun. In SDO’s view, the comet will appear to travel above the sun.
The exact dates of view for these observatories is as follows:
Nov 21–28: STEREO-A HI1 sees comet
Nov 26-29: STEREO-B coronagraphs sees comet
Nov 27-30: SOHO sees comet in coronagraphs
Nov 28-29: STEREO-A coronagraphs sees comet
Nov 28: SDO sees comet (for a few hours)
In addition, ground-based solar telescopes – observing in optical, infrared and radio wavelengths – will all be able to observe the comet during perihelion. Such observations will provide additional information about the composition of the comet and how material evaporates off it, fueling the dusty cloud that surrounds the nucleus.
One last solar effect could impact the comet at this stage in its journey. If the sun coincidentally sends out a giant cloud of solar particles, known as a coronal mass ejection, at the right time and direction to pass the comet, it could pull the comet’s tail right off.
If Comet ISON survives its trip around the sun, there’s a good chance that it will be incredibly bright and easily visible with the naked eye in the Northern Hemisphere. In early December, it will be seen in the morning, low on the horizon to the east-southeast. In late December and early January, it will be visible all night long.A second set of Chandra observations is planned for the middle of December to early January, when ISON will be passing through a transition region in the solar wind, where the hot wind from the Sun’s sun’s equator is mixed with a cooler wind produced by regions near the poles of the sun.
Closest approach to Earth, just a third of the distance between Earth and the sun, at approximately 2.8 million miles away.
The Real Cause Of Typhoid Fever Accidentally Discovered
July 20th, 2013
By Alton Parrish.
Image credit: blakespot via Flickr |
Typhoid fever is a disease that dates back to before ancient Greece and still causes as many as 200,000 deaths worldwide each year, roughly the population of Birmingham, Ala. For millennia, the cause of typhoid fever has remained a mystery. But a paper published last week in Nature revealed the true cause of the disease.
“It’s the oldest recognizable disease, it devastated Athens and is credited as the main reason why the Spartans beat the Athenians in war,” said Jorge Galan, the study’s author.
It’s been known for some time that the bacterium responsible for the disease is Salmonella typhi, but despite mankind’s long history with the microbe, “we’ve really been blindsided as to why this bug is so pathogenic, even though it’s a close cousin of the other salmonella sickness, food poisoning,” said Galan.
One of the reasons why humankind has been ignorant to the workings of S. typhi is because it’s a somewhat neglected disease without many researchers working on it, said leading typhoid fever expert Dr. Zulfiqar Bhutta, from Aga Khan University in Pakistan.
Galan’s research now discloses how S. typhi has managed to retain its stealth for so long. Its deadliness comes from a novel life strategy: it doesn’t release its toxin until it’s firmly inside a mammalian host cell. Normally when microbiologists search for a potential toxin produced by a microbe, they grow the organism in a culture and then grind it up and search for a candidate compound within the mixture. But S. typhi does not produce a toxin unless you’ve allowed it to enter a host cell, so you couldn’t possibly find it using conventional methods.
Galan, however, broke with protocol to look at the microbe after it had infected a host cell. “We happened to be studying the interaction of [S. typhi] with human cells, we weren’t in the business of trying to find the typhoid toxin, we just bumped into this,” said Galan.
Once inside a mammalian host cell, the typhoid bacterium begins to synthesize the toxin, which is then packaged into courier vessels to be unleashed.
“The toxin is dumped outside of the cell where the bacterium resides and it enters the blood system to hit its target,” said Galan.
Once Galan had identified what he thought could be the toxin responsible for typhoid disease, he isolated and purified it. He then infected mice with it and found that it did indeed result in typhoid symptoms in the mice, except fever, which is an immune response to the presence of the bacterium rather than the toxin itself.
“I think this is an absolutely fascinating paper, but it’s only the first step in the right direction,” said Bhutta. “This particular study looked at mutant strains [of S. typhi], the next step is to work out how much of this is true in real life. How much of this can be replicated by other researchers?”
Bhutta said that it’s still “too early to say whether this is a turning point or not,” towards the possible eradication of the disease.
Galan on the other hand said it will be “scientifically trivial” to synthesize an effective vaccine from an inactivated version of the toxin he discovered – though he concedes that the practicalities of the matter, such as finding enough funding, present a more formidable challenge.
Currently, typhoid treatment relies on a course of antibiotics that targets the bacteria rather than the toxin; occasionally even that fails.
“There are many instances in which people receive antibiotics but they still can’t pull out of the disease. Clearly the bacteria is no longer there. They eventually die. Our hypothesis is that the toxins are still circulating around,” said Galan.
Archaeologists Unearth More Than 300 Prehistoric Clay Figurines In Greece
July 19th, 2013
By University of South Hampton.
The Southampton team, working in collaboration with the Greek Archaeological Service and the British School at Athens, is studying the site of Koutroulou Magoula near the Greek village of Neo Monastiri, around 160 miles from Athens.
Koutroulou Magoula was occupied during the Middle Neolithic period (c. 5800 – 5300 BC) by a community of a few hundred people who made architecturally sophisticated houses from stone and mud-bricks. The figurines were found all over the site, with some located on wall foundations. It’s believed the purpose of figurines was not only as aesthetic art, but also to convey and reflect ideas about a community’s culture, society and identity.
“Figurines were thought to typically depict the female form, but our find is not only extraordinary in terms of quantity, but also quite diverse – male, female and non-gender specific ones have been found and several depict a hybrid human-bird figure,” says Professor Yannis Hamilakis, Co-Director of the Koutroulou Magoula Archaeology and Archaeological Ethnography project.
He continues, “We still have a lot of work to do studying the figurines, but they should be able to give us an enormous amount of information about how Neolithic people interpreted the human body, their own gender and social identity and experience.”
Excavations at Koutroulou Magoula were started in 2001 by Dr Nina Kyparissi (formerly Greek Archaeological Service) and this latest project began in 2010. The site is roughly four times the area of a football pitch and consists of a mound up to 18 feet high featuring at least three terraces surrounded by ditches. The people who lived in the settlement appear to have rebuilt their homes on the same building footprint generation after generation, and there is also evidence that some of the houses were unusual in their construction.
Professor Hamilakis comments, “This type of home would normally have stone foundations with mud-bricks on top, but our investigations at Koutroulou Magoula have found some preserved with stone walls up to a metre in height, suggesting that the walls may have been built entirely of stone, something not typical of the period.
“The people would have been farmers who kept domestic animals, used flint or obsidian1 tools and had connections with settlements in the nearby area. The construction of parts of the settlement suggests they worked communally, for example, to construct the concentric ditches surrounding their homes.
“There is no evidence of a central authority to date, yet large numbers of people were able to come together and carry out large communal and possibly socially beneficial projects.”
In later centuries, the settlement mount became an important memory place. For example, at the end of the Bronze Age, a ‘tholos’ or beehive-shaped tomb was constructed at the top and in Medieval times (12-13th c. AD) at least one person (a young woman) was buried amongst the Neolithic houses.
In addition to excavation, the project has conducted ethnography amongst the local communities, exploring their customs and culture and their relationship to the site. It has engaged in a series of community and public archaeology events, including the production and staging of site-specific theatrical performances, which turn into communal celebrations with food, drink and dance. In part, this aims to examine the importance of Koutroulou Magoula to contemporary communities and make the site an important feature in the social and cultural life of the area.
The project team will carry out two study seasons in 2013 and 2014.
Archaeology at Southampton: www.southampton.ac.uk/archaeology/index.page
Koutroulou Magoula Project Facebook page: www.facebook.com/groups/153333058025580
British School at Athens: www.bsa.ac.uk
Ping Pong Balls Break The Sound Barrier
July 18th, 2013
By Alton Parrish.
Getting students excited about science isn’t always easy, but having a live demonstration that uses ping pong balls traveling at supersonic speeds will get almost any kid’s attention.
Mechanical engineering and technology students at Purdue University built a supersonic, air-powered cannon that shoots ping pong balls at speeds so fast they break the sound barrier.
“We figured out it was coming out at about 919 miles an hour, and it was just mind-blowing,” said Craig Zehrung, a Ph.D. student at Purdue.
That is faster than an F-16 fighter jet at low speeds. Drawing upon his experience in the air force, mechanical engineer Mark French designed the cannon and turned a mundane class in to a fun learning experience.
“You shoot the gun, it makes this great big bang and the ball is in the barrel for, you know, milliseconds, and nobody thinks of ping pong balls as going very fast,” said French.
Soda cans ripped apart by ping pong ball
Credit: Purdue University
A vacuum pump sucks the air out of a sealed tube and air rushes into a special hourglass-shaped nozzle, just like those in F-16 engines. The nozzle accelerates the ball to supersonic speeds, propelling it with incredible momentum through wood, soda cans, and even denting steel.
“You can get really, really high accelerations, the ball comes out of the barrel intact and doesn’t break until it actually hits something,” said French.
Researchers were surprised by the supersonic speeds because the lightweight balls have poor aerodynamics. Despite their measly 2.3 grams, the balls delivered a startling amount of energy to targets: the equivalent of a 125 mile-per-hour fastball or a brick falling several stories.
“Obviously the main thing is how do we make it go faster, how we get more boom out of any device, right?” commented Zehrung.
The engineers do caution that this should not be done at home. It should only be done in a safe lab environment.
Contacts and sources:
Karin Heineman executive producer
Inside Science TV
Penn Anthropologists Clarify Link Between Asians And Early Native Americans
July 17th, 2013
By Alton Parrish.
Credit: University of Pennsylvania
The team’s study, published in the American Journal of Human Genetics, analyzed the genetics of individuals living in Russia’s Altai Republic to identify markers that might link them to Native Americans. Prior ethnographic studies had found distinctions between tribes in the northern and southern Altai, with the northern tribes apparently linked linguistically and culturally to ethnic groups farther to the north, such as the Uralic or Samoyedic populations, and the southern groups showing a stronger connection to Mongols, Uighurs and Buryats.
Schurr and colleagues assessed the Altai samples for markers in mitochondrial DNA, which is maternally inherited, and in Y chromosome DNA, which is passed from fathers to sons. They also compared the samples to ones previously collected from individuals in southern Siberia, Central Asia, Mongolia, East Asia and a variety of American indigenous groups. Because of the large number of gene markers examined, the findings have a high degree of precision.
“At this level of resolution we can see the connections more clearly,” Schurr said.
Looking at the Y chromosome DNA, the researchers found a unique mutation shared by Native Americans and southern Altaians in the lineage known as Q.
“This is also true from the mitochondrial side,” Schurr said. “We find forms of haplogroups C and D in southern Altaians and D in northern Altaians that look like some of the founder types that arose in North America, although the northern Altaians appeared more distantly related to Native Americans.”
Calculating how long the mutations they noted took to arise, Schurr’s team estimated that the southern Altaian lineage diverged genetically from the Native American lineage 13,000 to 14,000 years ago, a timing scenario that aligns with the idea of people moving into the Americas from Siberia between 15,000 and 20,000 years ago.
Though it’s possible, even likely, that more than one wave of people crossed the land bridge, Schurr said that other researchers have not yet been able to identify a similar geographic focal point from which Native Americans can trace their heritage.
“It may change with more data from other groups, but, so far, even with intensive work in Mongolia, they’re not seeing the same things that we are,” he said.
In addition to elucidating the Asia-America connection, the study confirms that the modern cultural divide between southern and northern Altaians has ancient genetic roots. Southern Altaians appeared to have had greater genetic contact with Mongolians than they did with northern Altaians, who were more genetically similar to groups farther to the north.
However, when looking at the Altaians’ mitochondrial DNA in isolation, the researchers did observe greater connections between northern and southern Altaians, suggesting that perhaps females were more likely to bridge the genetic divide between the two populations.
“Subtle differences here both reflect the Altaians themselves — the differentiation among those groups — and allow us to try to point to an area where some of these precursors of American Indian lineages may have arisen,” Schurr said.
Moving forward, Schurr and his team hope to continue to use molecular genetic techniques to trace the movement of peoples within Asia and into and through the Americas. They may also attempt to identify links between genetic variations and adaptive physiological responses, links that could inform biomedical research.
For example, Schurr noted that both Siberians and Native American populations “seem to be susceptible to Westernization of diet and moving away from traditional diets, but their responses in terms of blood pressure and fat metabolism and so forth actually differ.”
Using genomic approaches along with traditional physical anthropology may lend insight into the factors that govern these differences.
In addition to Schurr and Dulik, the research was conducted by Sergey Zhadanov, Ayken Askapuli, Lydia Gau, Omer Gokcumen and Samara Rubinstein of Penn’s Department of Anthropology.
The study was supported by the University of Pennsylvania, the National Science Foundation, the Social Sciences and Humanities Research Council of Canada and the Russian Basic Fund for Research. The National Geographic Society also provided infrastructural support to the Schurr lab.
A few Coolest Historic Bars Around The U.S.
July 15th, 2013By Alton Parrish.
Going back to before the War of Independence, how many conversations in bars, over a beer, ale, or cider, have possibly inspired revolutions in art or in politics? When you take into account the pubs and cafes across the planet, trying to account for the number of historical dramas that unfolded after a few drinks can be overwhelming. Maybe this is why historical bars are so much fun. You can feelhistory, or at least imagine that you do, as you enjoy what may be the same bar stool Lord Byron, Ernest Hemmingway, or Jean Lafitte once sat on. Here is a list, by no means comprehensive, of some of the coolest historical bars to be found in the U.S., as well as London and Paris.
The Green Dragon Tavern (Boston, MA)
Established in 1654, The Green Dragon Tavern’s website insists the watering hole played a decisive role in the War of Independence, as it was there that plans for the invasion of Lexington and Concorde were overheard, prompting the famous ride of Green Dragon patron Paul Revere. This isn’t completely accurate, although in those days, Revere certainly did enjoy a drink or two at the tavern. John Hancock was another famous patron, his brother lived next door. Full bands play onstage now in what is one of the oldest and most popular bars in Boston.
The Spaniards Inn (Hampstead, London)
In London, there are no shortages of pubs and folks who love a good pint. The historic 16th century Spaniards Inn is mentioned in both Charles Dickens’Pickwick Papers and Bram Stoker’s Dracula, and served both poets Lord Byron and John Keats, who wrote “Ode to a Nightingale” while sipping a claret. Today, the pub boasts a backyard “dog-friendly beer garden” complete with a dog-wash. It’s the perfect spot to read, wash your dog, and enjoy a variety of ales and ciders.
Napoleon House (New Orleans, LA)
Napoleon House, a building that includes a bar, opened up in 1797. The building’s first occupant, Nicholas Girod, was mayor of New Orleans from 1812 to 1815. Being a proud French Quarter resident, Girod offered Napoleon himself refuge at the residence in 1821, a gesture that would give the establishment its name. Peeling paint, arched doorways, wood worn surfaces, and a clientele that includes artists, writers, and professional alcoholics, all give Napoleon House its justified charm and historical vibe.
McSorley’s Old Ale House (New York, NY)
Many of our county’s oldest bars are located in New York City. Established in 1854, located at 15 East 7th street, McSorely’s Old Ale House is the city’s oldest, continuously operated saloon. It also enjoys the dubious distinction of denying women entrance through its swinging doors until 1970. Abraham Lincoln visited McSorely’s, as did Woody Guthrie, and John Lennon (We’re not sure if Yoko Ono was allowed in or not.). Visit McSorely’s, and you can try to sort out its contradictory history over a draft or two (or three).
Harry’s New York Bar is actually located in Paris, France. Originally located in New York City, the bar was dismantled in 1911, and brought over to Rue Daunou Paris in pieces to be rebuilt. Its famous patrons include Coco Chanel, Ernest Hemmingway, F. Scott Fitzgerald, and Jean-Paul Sartre. Some sources say that George Gershwin composed his popular, programmatic orchestral piece “An American in Paris” on the bar’s piano. The bar’s interior is decorated with American memorabilia, which may or may not be of much interest to the French, but certainly helps 21st century expats feel right at home.
Located on North Broadway Avenue in Chicago, The Green Mill Jazz Club is a hotspot for hearing jazz in all of it forms, played by musicians both young and old alike. Jam sessions until dawn are not uncommon. The Green Mill was established in 1907, and was a favorite hang of gangster Al Capone, silent comedian Charlie Chaplin, and singer Frank Sinatra. During Prohibition, The Green Mill was a speakeasy, and still has a trapdoor behind the bar leading to tunnels that were used to illegally deliver alcohol.
There is a lot of history to explore throughout the city of Columbus, a major American test market that is currently enjoying a rep as a foodie’s paradise. The Jury Room, located at 22 East Mound Street, was built in 1831, to serve those visiting the Courthouse across the street. It has operated continuously, even through the years of Prohibition, ever since. The building, like most of the historic bars we are listing, is haunted. Indoor lights that are turned off mysteriously come back on, and a back gate that’s always locked sometimes squeaks ominously, as if someone is passing through.
Everywhere you look in downtown Savannah, you’re confronted with history. Since it opened in 1890, The Rail Pub, located at 405 West Congress Street, has operated as a boarding house and a brothel, as its location used to be Savannah’s own “Red Light” district. Day laborers used to gather in Franklin Square, across the street from the pub, and wait for work on the railroad. At the end of a day, they would come to The Rail for a drink, thus inspiring its name.
Lafitte’s Blacksmith Shop Bar (New Orleans, LA)
This establishment, built between 1722-1732, is named after the privateer (i.e. “pirate”), entrepreneur (i.e. “gangster”), and sailor (i.e. again, “pirate”) of the Battle of New Orleans, Jean Lafitte. Located in the French Quarter, and lit mostly by candlelight, Lafitte’s Blacksmith Shop features well-priced drinks and plenty free-of-charge “old-world charm.” The bar’s website indicates it is “the only known watering hole that pre-dates our nation’s independence.” But what about the aforementioned Green Dragon Tavern which was established in 1654? The answer may be a matter of historical interpretation, best discussed and debated over a drink or two. Cheers!
First Interspecies Transplant, Goal Is Animal to Human Transplant Of Insulin Producing Cells Without Drugs
July 15th, 2013By Alton Parrish.
In the first step toward animal-to-human transplants of insulin-producing cells for people with type 1 diabetes, Northwestern Medicine® scientists have successfully transplanted islets, the cells that produce insulin, from one species to another. And the islets survived without immunosuppressive drugs. Northwestern scientists developed a new method that prevented rejection of the islets, a huge problem in transplants between species, called xenotransplantation.
Credit: Wikipedia
by Marla Paul
Northwestern University
Norwegian Researcher Unlocks Construction Secrets Of The Pyramids
July 13th, 2013
By Alton Parrish.
For thousands of years, scientists from around the world have tried to understand how the Egyptians erected their giant pyramids. Now, an architect and researcher at the Norwegian University of Science and Technology (NTNU) says he has the answer to this ancient, unsolved puzzle.
Researchers have been so preoccupied by the weight of the stones that they tend to overlook two major problems: How did the Egyptians know exactly where to put the enormously heavy building blocks? And how was the master architect able to communicate detailed, highly precise plans to a workforce of 10,000 illiterate men?
The Cheops Pyramid
Photo credit Havard Houen
These were among the questions that confronted Ole J. Bryn, an architect and associate professor in NTNU’s Faculty of Architecture and Fine Art when he began examining Khufu’s Great Pyramid in Giza. Khufu’s pyramid, better known as the Pyramid of Cheops, consists of 2.3 million limestone blocks weighing roughly 7 million tons. At 146.6 meters high, it held the record as the tallest structure ever built for nearly 4000 years.
What Bryn discovered was quite simple. He believes that the Egyptians invented the modern building grid, by separating the structure’s measuring system from the physical building itself, thus introducing tolerance, as it is called in today’s engineering and architectural professions.
The building grid for the Cheops Pyramid, as drawn by Norwegian University of Science and Technology architect and Associate Professor Ole J. Bryn
Bryn has studied the plans from the thirty oldest Egyptian pyramids, and discovered a precision system that made it possible for the Egyptians to reach the pyramid’s last and highest point, the apex point, with an impressive degree of accuracy. By exploring and making a plan of the pyramid it is possible to prepare modern project documentation of not just one, but all pyramids from any given period.
As long as the architect knows the main dimensions of a pyramid, he can project the building as he would have done it with a modern building, but with building methods and measurements known from the ancient Egypt, Bryn says.
In a scientific article published in May 2010 (Retracing Khufu’s Great Pyramid in the Nordic Journal of Architectural Research, 1-2 2010) Bryn discusses aspects that can explain the construction of a multitude of the Egyptian pyramids by taking the building grid, and not the physical building itself, as the starting point for the analysis.
If the principles behind Bryn’s drawings are correct, then archaeologists will have a new “map” that demonstrates that the pyramids are not a “bunch of heavy rocks with unknown structures” but, rather, incredibly precise structures.
Ole J. Bryn’s findings will be presented and explained at the exhibition The Apex Point in Trondheim, Norway from September 13 to October 1, and in a forthcoming book to be published in the spring of 2011. The exhibition is an official part of the programme celebrating the centenary (1910-2010) of the Norwegian University of Science and Technology.
Contacts and sources:
Norwegian University of Science and Technology news release
Solar Tsunami Used To Measure Sun’s Magnetic Field
July 13th, 2013
By University Of College London.
Solar tsunamis are produced by enormous explosions in the Sun’s atmosphere called coronal mass ejections (CMEs). As the CME travels out into space, the tsunami travels across the Sun at speeds of up to 1000 kilometres per second.
Credit: NASA/SDO/AIA
Dr David Long, UCL Mullard Space Science Laboratory, and lead author of the research, said: “We’ve demonstrated that the Sun’s atmosphere has a magnetic field about ten times weaker than a normal fridge magnet.”
Using data obtained using the Extreme ultraviolet Imaging Spectrometer (EIS), a UK-led instrument on the Japanese Hinode spacecraft, the team measured the density of the solar atmosphere through which the tsunami was travelling.
The combination of imaging and spectral observations provides a rare opportunity to examine the magnetic field which permeates the Sun’s atmosphere.
Dr Long noted: “These are rare observations of a spectacular event that reveal some really interesting details about our nearest star.”
Visible as loops and other structures in the Sun’s atmosphere, the Sun’s magnetic field is difficult to measure directly and usually has to be estimated using intensive computer simulations. The Hinode spacecraft has three highly sensitive telescopes, which use visible, X-ray and ultraviolet light to examine both slow and rapid changes in the magnetic field.
The instruments on Hinode act like a microscope to track how the magnetic field around sunspots is generated, shapes itself, and then fades away. These results show just how sensitive these instruments can be, measuring magnetic fields that were previously thought too weak to detect.
The explosions that produce solar tsunamis can send CMEs hurtling towards the Earth. Although protected by its own magnetic field, the Earth is vulnerable to these solar storms as they can adversely affect satellites and technological infrastructure.
Dr Long said: “As our dependency on technology increases, understanding how these eruptions occur and travel will greatly assist in protecting against solar activity.”
Outdated Practice Of Annual Cervical-Cancer Screenings May Cause More Harm Than Good
July 11th, 2013
By University of North Carolina.
Despite the revised guidelines, about half of the obstetrician-gynecologists surveyed in a recent study said they continue to provide annual exams – an outdated practice that may be more harmful than helpful, said Drs. Russell Harris and Stacey Sheridan of the Cecil G. Sheps Center for Health Services Research at the University of North Carolina at Chapel Hill.
“Screening is not the unqualified good that we have advertised it to be,” they wrote in an editorial titled, “The Times They (May Be) A-Changin’: Too Much Screening is a Health Problem.” The editorial accompanied a research study reviewing physician practices around cervical-cancer screening and vaccination for human papilloma virus (HPV), which has been linked to cervical cancer.
The study, “Physicians Slow to Implement HPV Vaccination and Cervical Screening Guidelines,” was published July 9 in the American Journal of Preventive Medicine.
“Screening for cervical cancer and other cancers such as breast and prostate, has clear potential for harms as well as benefits, and these must be carefully weighed before a rational decision about screening can be made,” wrote Harris and Sheridan, who are professor and assistant professor of medicine, respectively, at UNC’s School of Medicine. They also hold adjunct appointments at UNC’s Gillings School of Global Public Health.
The study noted physicians said they were comfortable with longer testing intervals, but were concerned their patients might not come in for annual check-ups if Pap tests, the screening test for cervical cancer, were not offered. The problem, Harris said, is that annual Pap tests produce more abnormal results leading to additional, invasive testing that itself bring risks.
“Many women have ‘abnormal’ [Pap test] findings that are not cancer, but may be a ‘cancer precursor.’ We know that the great majority of these abnormal findings would never progress to actual invasive cancer, yet these women are referred” for further, more invasive testing, Harris said.
One such test, called a “colposcopy,” [cohl-PAH-scoh-pee], involves examining the cervix for possibly cancerous lesions, followed frequently by a biopsy, i.e., taking a small sample of the lesion, which can cause pain and bleeding, as well as potential psychological harm. “The screening test itself can raise concern about dreaded cancer; a positive screening test heightens this worry; finding a cancer precursor, even one of uncertain importance, just increases worry further,” they wrote.
The authors recognize the important benefit of screening for cervical and other cancers, but “screening every three years [for cervical cancer] retains about 95 percent of the benefit of annual screening, but reduces harms by roughly two-thirds.” Less-frequent screening also reduces costs significantly in terms of patient and physician time and laboratory testing supplies and other resources.
The newest cervical-cancer and HPV screening recommendations were released in March 2012, too recent to have been included in the July 9 study. Women should still begin Pap tests at age 21 and every three years afterward, but women between the ages of 30 and 65 may choose to extend the Pap test interval to every five years, provided they also get an HPV test, according to the U.S. Preventive Services Task Force and the American Cancer Society, among others. However, the authors added, “the debate about a do-less approach to screening—for cervical cancer and other conditions as well—is ongoing.”
The editorial concluded: “Bob Dylan sang about changing times before they actually changed, yet his singing moved the public discussion in a positive direction. Our sense is that the right song for the current discussion is about helping people come to appreciate the harms screening does … and move us toward a better balance of benefits and harms.”
Egyptian Leader Makes Surprise Appearance At Archaeological Dig In Israel
July 11th, 2013
By Alton Parrish.
At a site in Tel Hazor National Park, north of the Sea of Galilee, archeologists from the Hebrew University of Jerusalem have unearthed part of a unique Sphinx belonging to one of the ancient pyramid-building pharaohs.
The Hazor Excavations are headed by Prof. Amnon Ben-Tor, the Yigael Yadin Professor in the Archaeology of Eretz Israel at the Hebrew University’s Institute of Archaeology, and Dr. Sharon Zuckerman, a lecturer at the Hebrew University’s Institute of Archaeology.
Working with a team from the Institute of Archaeology, they discovered part of a Sphinx brought over from Egypt, with a hieroglyphic inscription between its front legs. The inscription bears the name of the Egyptian king Mycerinus, who ruled in the third millennium BCE, more than 4,000 years ago. The king was one of the builders of the famous Giza pyramids.
As the only known Sphinx of this king discovered anywhere in the world — including in Egypt — the find at Hazor is an unexpected and important discovery. Moreover, it is only piece of a royal Sphinx sculpture discovered in the entire Levant area (the eastern part of the Mediterranean).
Along with the king’s name, the hieroglyphic inscription includes the descriptor “Beloved by the divine manifestation… that gave him eternal life.” According to Prof. Ben-Tor and Dr. Zuckerman, this text indicates that the Sphinx probably originated in the ancient city of Heliopolis (the city of ‘On’ in the Bible), north of modern Cairo.
The Sphinx was discovered in the destruction layer of Hazor that was destroyed during the 13th century BCE, at the entrance to the city palace. According to the archaeologists, it is highly unlikely that the Sphinx was brought to Hazor during the time of Mycerinus, since there is no record of any relationship between Egypt and Israel in the third millennium BCE.
More likely, the statue was brought to Israel in the second millennium BCE during the dynasty of the kings known as the Hyksos, who originated in Canaan. It could also have arrived during the 15th to 13th centuries BCE, when Canaan was under Egyptian rule, as a gift from an Egyptian king to the king of Hazor, which was the most important city in the southern Levant at the time.
Hazor is the largest biblical-era site in Israel, covering some 200 acres, and has been recognized as a World Heritage Site by UNESCO. The population of Hazor in the second millennium BCE is estimated to have been about 20,000, making it the largest and most important city in the entire region. Its size and strategic location on the route connecting Egypt and Babylon made it “the head of all those kingdoms” according to the biblical book of Joshua (Joshua 11:10). Hazor’s conquest by the Israelites opened the way to the conquest and settlement of the Israelites in Canaan. The city was rebuilt and fortified by King Solomon and prospered in the days of Ahab and Jeroboam II, until its final destruction by the Assyrians in 732 BCE.
Documents discovered at Hazor and at sites in Egypt and Iraq attest that Hazor maintained cultural and trade relations with both Egypt and Babylon. Artistic artifacts, including those imported to Hazor from near and far, have been unearthed at the site. Hazor is currently one of Israel’s national parks.
The Hebrew University began the Hazor excavation in the mid-1950s and continued them in the late 1960s. Excavations at the site were resumed in 1990 by Prof. Amnon Ben-Tor, who was joined in 2006 by Dr. Sharon Zuckerman, as part of the Selz Foundation Hazor Excavations in Memory of Yigael Yadin. The present excavation area is managed by Shlomit Becher, a doctoral student of the Hebrew University’s Institute of Archaeology, and is sponsored by the Israel Exploration Society (IES) in cooperation with the Israel Antiquities Authority and the Israel Nature and Parks Authority.
Hebrew University of Jerusalem
Meteorite Mystery
July 9th, 2013University of Chicago.
This is an artist’s rendition of a sun-like star as it might have looked at one million years of age. As a cosmochemist, the University of Chicago’s Lawrence Grossman reconstructs the sequence of minerals that condensed from the solar nebula, the primordial gas cloud that eventually formed the sun and planets.
Illustration by NASA/JPL-Caltech/T. Pyle, SSC
Credit: University of Chicago
Researchers have continued to regard chondrules as liquid droplets that had been floating in space before becoming quickly cooled, but how did the liquid form? “There’s a lot of data that have been puzzling to people,” Grossman said.
Grossman’s research reconstructs the sequence of minerals that condensed from the solar nebula, the primordial gas cloud that eventually formed the sun and planets. He has concluded that a condensation process cannot account for chondrules. His favorite theory involves collisions between planetesimals, bodies that gravitationally coalesced early in the history of the solar system. “That’s what my colleagues found so shocking, because they had considered the idea so ‘kooky,’” he said.
Cosmochemists know for sure that many types of chondrules, and probably all of them, had solid precursors. “The idea is that chondrules formed by melting these pre-existing solids,” Grossman said.
Photo by Steven Simon
One problem concerns the processes needed to obtain the high, post-condensation temperatures necessary to heat the previously condensed solid silicates into chondrule droplets. Various astonishing but unsubstantiated origin theories have emerged. Maybe collisions between dust particles in the evolving solar system heated and melted the grains into droplets. Or maybe they formed in strikes of cosmic lightning bolts, or condensed in the atmosphere of a newly forming Jupiter.
Another problem is that chondrules contain iron oxide. In the solar nebula, silicates like olivine condensed from gaseous magnesium and silicon at very high temperatures. Only when iron is oxidized can it enter the crystal structures of magnesium silicates. Oxidized iron forms at very low temperatures in the solar nebula, however, only after silicates like olivine had already condensed at temperatures 1,000 degrees higher.
At the temperature at which iron becomes oxidized in the solar nebula, though, it diffuses too slowly into the previously formed magnesium silicates, such as olivine, to give the iron concentrations seen in the olivine of chondrules. What process, then, could have produced chondrules that formed by melting pre-existing solids and contain iron oxide-bearing olivine?
“Impacts on icy planetesimals could have generated rapidly heated, relatively high-pressure, water-rich vapor plumes containing high concentrations of dust and droplets, environments favorable for formation of chondrules,” Grossman said. Grossman and his UChicago co-author, research scientist Alexei Fedkin, published their findings in the July issue of Geochimica et Cosmochimica Acta.
Grossman and Fedkin worked out the mineralogical calculations, following up earlier work done in collaboration with Fred Ciesla, associate professor in geophysical sciences, and Steven Simon, senior scientist in geophysical sciences. To verify the physics, Grossman is collaborating with Jay Melosh, University Distinguished Professor of Earth & Atmospheric Sciences at Purdue University, who will run additional computer simulations to see if he can recreate chondrule-forming conditions in the aftermath of planetesimal collisions.
“I think we can do it,” Melosh said.
LONGSTANDING OBJECTIONS
Grossman and Melosh are well-versed in the longstanding objections to an impact origin for chondrules. “I’ve used many of those arguments myself,” Melosh said.
Grossman re-evaluated the theory after Conel Alexander at the Carnegie Institution of Washington and three of his colleagues supplied a missing piece of the puzzle. They discovered a tiny pinch of sodium—a component of ordinary table salt—in the cores of the olivine crystals embedded within the chondrules.
When olivine crystallizes from a liquid of chondrule composition at temperatures of approximately 2,000 degrees Kelvin (3,140 degrees Fahrenheit), most sodium remains in the liquid if it doesn’t evaporate entirely. But despite the extreme volatility of sodium, enough of it stayed in the liquid to be recorded in the olivine, a consequence of the evaporation suppression exerted by either high pressure or high dust concentration. According to Alexander and his colleagues, no more than 10 percent of the sodium ever evaporated from the solidifying chondrules.
Grossman and his colleagues have calculated the conditions required to prevent any greater degree of evaporation. They plotted their calculation in terms of total pressure and dust enrichment in the solar nebula of gas and dust from which some components of the chondrites formed. “You can’t do it in the solar nebula,” Grossman explained. That’s what led him to planetesimal impacts. “That’s where you get high dust enrichments. That’s where you can generate high pressures.”
When the temperature of the solar nebula reached 1,800 degrees Kelvin (2,780 degrees Fahrenheit), it was too hot for any solid material to condense. By the time the cloud had cooled to 400 degrees Kelvin (260 degrees Fahrenheit), however, most of it had condensed into solid particles. Grossman has devoted most of his career to identifying the small percentage of substances that materialized during the first 200 degrees of cooling: oxides of calcium, aluminum and titanium, along with the silicates. His calculations predict condensation of the same minerals that are found in meteorites.
Over the last decade, Grossman and his colleagues have written a slew of papers exploring various scenarios for stabilizing iron oxide enough that it would enter the silicates as they condensed at high temperatures, none of which proved feasible as an explanation for chondrules. “We’ve done everything that you can do,” Grossman said.
This included adding hundreds or even thousands of times the concentrations of water and dust that they had any reason to believe ever existed in the early solar system. “This is cheating,” Grossman admitted. It didn’t work anyway.
Instead, they added extra water and dust to the system and increased its pressure to test a new idea that shock waves might form chondrules. If shock waves of some unknown source had passed through the solar nebula, they would have rapidly compressed and heated any solids in their path, forming chondrules after the melted particles cooled off. Ciesla’s simulations showed that a shock wave can produce silicate liquid droplets if he increased the pressure and the quantities of dust and water by these abnormally if not impossibly high amounts, but the droplets would be different from the chondrules actually found in meteorites today.
COSMIC SHOVING MATCH
They differ in that actual chondrules contain no isotopic anomalies, whereas the simulated shock-wave chondrules do. Isotopes are atoms of the same element that have different masses from one another. The evaporation of atoms of a given element from droplets drifting through the solar nebula causes the production of isotopic anomalies, which are deviations from the normal relative proportions of the element’s isotopes. It’s a cosmic shoving match between dense gas and hot liquid. If the number of a given type of atoms pushed out of the hot droplets equals the number of atoms getting pushed in from the surrounding gas, no evaporation will result. This prevents isotope anomalies from forming.
The olivine found in chondrules presents a problem. If a shock wave formed the chondrules, then the olivine’s isotopic composition would be concentrically zoned, like tree rings. As the droplet cools, olivine crystallizes with whatever isotopic composition existed in the liquid, starting at the center, then moving out in concentric rings. But no one has yet found isotopically zoned olivine crystals in chondrules.
Realistic-looking chondrules would result only if evaporation were suppressed enough to eliminate the isotope anomalies. That, however, would require higher pressure and dust concentrations that go beyond the range of Ciesla’s shock-wave simulations.
Providing some help was the discovery a few years ago that chondrules are one or two million years younger than calcium-aluminum-rich inclusions in meteorites. These inclusions are exactly the condensates that cosmochemical calculations dictate would condense in the solar nebular cloud. That age difference provides enough time after condensation for planetesimals to form and start colliding before chondrules form, which then became part of Fedkin and Grossman’s radical scenario.
They now say that planetesimals consisting of metallic nickel-iron, magnesium silicates and water ice condensed from the solar nebula, well ahead of chondrule formation. Decaying radioactive elements inside the planetesimals provided enough heat to melt the ice.
The water percolated through the planetesimals, interacted with the metal and oxidized the iron. With further heating, either before or during planetesimal collisions, the magnesium silicates re-formed, incorporating iron oxide in the process. When the planetesimals then collided with each other, generating the abnormally high pressures, liquid droplets containing iron oxide sprayed out.
“That’s where your first iron oxide comes from, not from what I’ve been studying my whole career,” Grossman said. He and his associates have now reconstructed the recipe for producing chondrules. They come in two “flavors,” depending on the pressures and dust compositions arising from the collision.
“I can retire now,” he quipped.
Citation: “Vapor saturation of sodium: Key to unlocking the origin of chondrules,” by Alexei V. Fedkin and Lawrence Grossman, Geochimica et Cosmochimica Acta, Vol. 112, July 2013, pages 226-250.
Funding: National Aeronautics and Space Administration
– See more at: http://news.uchicago.edu/article/2013/07/08/cosmochemist-discovers-potential-solution-meteorite-mystery#sthash.42govANZ.dpuf
Cyrus Cylinder: First Bill Of Human Rights Is 2600 Years Old
July 9th, 2013
The Cyrus Cylinder, sometimes referred to as the first “bill of human rights,” traces its origins to the Persian king Cyrus the Great’s conquest of Babylon in the sixth century B.C. Almost 2,600 years later, its remarkable legacy continues to shape contemporary political debates, cultural rhetoric and philosophy.
One of the most celebrated objects in world history made its U.S. debut March 9 when “The Cyrus Cylinder and Ancient Persia” opened at the Arthur M. Sackler Gallery. On loan from the British Museum, the Cylinder will be on view at the Sackler through April 28, travelling afterwards to Houston, New York, San Francisco and Los Angeles.
“You could almost say that the Cyrus Cylinder is a history of the Middle East in one object, creating a link to a past that we all share and to a key moment in history that has shaped the world around us,” said Neil MacGregor, director of the British Museum. “Objects are uniquely able to speak across time and space, and this object must be shared as widely as possible.”
The Cylinder—a football-sized, barrel-shaped clay object covered in Babylonian cuneiform, one of the earliest written languages—announced Cyrus’ victory and his intention to allow freedom of worship to communities displaced by the defeated ruler Nabonidus. At the time, such declarations were not uncommon, but Cyrus’ was unique in its nature and scope. When contextualized with other contemporary sources, such as the Bible’s Book of Ezra, it becomes evident that Cyrus allowed displaced Jews to return to Jerusalem.
“One of the goals of this exhibition is to encourage us to reflect that relations between Persians and Jews have not always been marked by the discord that disfigures the political map of the Near East today,” said Julian Raby, The Dame Jillian Sackler Director of the Arthur M. Sackler Gallery and the Freer Gallery of Art. “Cyrus was the very image of a virtuous rule¬—inspiring leaders from Alexander the Great to Thomas Jefferson—so it is apt that the first time it will be seen in the West is in Washington, D.C.”
Under Cyrus (ca. 580–530 B.C.), the Persian Empire became the largest and most diverse the world had known to that point. Subsequent generations of rulers considered it to be the ideal example of unified governance across multiple cultures, languages and vast distances. Cyrus’ declarations of tolerance, justice and religious freedom provided inspiration for generations of philosophers and policymakers, from Ancient Greece to the Renaissance, and from the Founding Fathers to modern-day Iran, so much so that a copy now resides in the United Nations’ headquarters in New York.
The message of the Cylinder and the larger legacy of Cyrus’ leadership have been appropriated and reinterpreted over millenia, beginning with its creators. The Babylonian scribe who engraved the Cylinder attributed Cyrus’ victory to the Babylonian god Marduk, a stroke of what could be considered royal and religious propaganda. In the fourth century B.C., the Greek historian Xenophon wrote Cyropaedia, a text that romanticizes the philosophies and education of Cyrus as the ideal ruler, which greatly influenced both Alexander the Great and, much later, Thomas Jefferson in his creation of the Declaration of Independence.
When the Cylinder was rediscovered in 1879, it immediately entered the fray of public debate as invaluable proof of the historical veracity of events described in biblical scripture. In the early 20th century, supporters of the creation of the state of Israel compared the actions of British King George V to those of Cyrus, allowing Jews to return to Jerusalem. When the Cylinder was loaned to Iran in 2010, it was viewed by more than 1 million people, one of the most visited exhibitions in the country’s history.
“The Cyrus Cylinder and Ancient Persia” includes related objects that highlight some of the artistic, cultural and historical achievements of the Achaemenid Empire (550–330 B.C.) of Iran, such as architectural fragments, finely carved seals and luxury objects from the Oxus Treasure. Curated by John Curtis, Keeper of Special Middle East Projects at the British Museum, the show will travel to the Museum of Fine Arts in Houston, the Metropolitan Museum of Art in New York, the Asian Art Museum in San Francisco and the J. Paul Getty Museum at the Getty Villa in Los Angeles through October.
The exhibition is organized by the British Museum in partnership with the Iran Heritage Foundation and the Arthur M. Sackler Gallery, Smithsonian Institution, and is supported by an indemnity from the Federal Council on the Arts and the Humanities. Additional support for the Sackler’s presentation is provided by the Leon Levy Foundation, the Ebrahimi Family Foundation and the Foundation for Iranian Studies.
The Arthur M. Sackler Gallery, located at 1050 Independence Avenue S.W., and the adjacent Freer Gallery of Art, located at 12th Street and Independence Avenue S.W., are on the National Mall in Washington, D.C. Hours are 10 a.m. to 5:30 p.m. every day (closed Dec. 25), and admission is free. The galleries are located near the Smithsonian Metrorail station on the Blue and Orange lines. For more information about the Freer and Sackler galleries and their exhibitions, programs and other public events, visit www.asia.si.edu. For general Smithsonian information, call (202) 633-1000.
Winds And Clouds On Eight ‘Hot Jupiter’ Exoplanets Play An Important Role In The Atmospheric Make Up Of These Exotic Planets
July 7th, 2013
By Alton Parrish.
Hot Jupiters are giant exoplanets, similar in size to Jupiter, that orbit so close to their stars that their atmospheres can reach temperatures of 1000-3000 degrees Celsius. Astronomers can detect which gases are present in their atmospheres by analysing the spectrum of starlight filtered through the planet’s atmosphere when the planet passes in front of the star. Last year, a team led by the University of Exeter was awarded nearly 200 hours on the NASA/ESA Hubble Space Telescope to examine eight planets using this technique – the largest survey of its type to date.
“These hot Jupiter planets are expected to have a vastly different composition from planets in our own Solar System like Jupiter, where temperatures at the cloud tops are around -150 degrees Celsius. The first planet we measured is one of the hottest to be observed, with a temperature of over 2000 degrees. The early results of the survey are now in, and they present a diverse range of puzzling properties,” said Huitson.
Huitson explained, “Titanium oxide is a solid on Earth, but we expect it to be present in the atmosphere of the hottest hot Jupiters because of the extreme temperatures. This molecule is important because it could trap atmospheric heat high up forming a stratosphere – the same role ozone plays on Earth. However, our results show that this molecule is not present in the upper atmosphere, meaning that we need to revise our understanding of how wind processes distribute materials.”
The team also made a confirmed detection of water vapour in the atmosphere of two planets. Importantly, the water was found in the quantities predicted by theory, contrasting with previously observed planets.
“While our models tell us that water (as steam) should be present in hot Jupiter atmospheres, until now the molecule has only been seen in limited quantities and in fewer planets than expected,” said Huitson.
“Seeing steam in two exoplanets is a great confirmation of current theory. Our new findings suggest that previous non-detections were caused by opaque, high-up clouds obscuring the parts of the atmosphere where steam is present.”
The results presented at the National Astronomy Meeting represent initial findings and work by the team is still ongoing to analyse all the data from the eight-planet Hubble survey.
“A surprising diversity is emerging from the continuing observations among planets with similar temperatures, and the remaining results are sure to present even more surprises as we try to understand such extreme and unknown objects,” said Huitson.
Earliest Evidence Of Using Flower Beds For Burial Found In Holy Land Cave In Mt. Carmel, 13,700 Year Old Grave
July 7th, 2013
By University of Haifa.
The Natufians, who lived some 15,000-11,500 years ago, were of the first in the world to abandon nomadic life and settle in permanent settlements, setting up structures with stone foundations. They were also among the first to establish cemeteries – confined areas in which they buried their community members for generations. The cemeteries were usually located at the first chambers of caves or on terraces located below the caves. In contrast, earlier cultures used to bury their dead (if at all) randomly. Mt. Carmel was one of the most important and densely populated areas in the Natufian settlement system. Its sites have been explored by University of Haifa archeologists for dozens of years.
A Natufian cemetery containing 29 skeletons of babies, children and adults was discovered at Raqefet cave. Most of the burials were single interments, although some were double, in which two bodies were interred together in the same pit. In fours graves, researchers found plant impressions on a thin layer of mud veneer which was presumably spread like plaster inside the grave. Before burying the bodies, the Natufians spread a bed of blooming green plants inside the graves. The impressions are mostly of plants with square stems, common among the mint family. In one incident, flowering stems of Judean Sage were found, one of three Sage species currently growing in the vicinity of the cave. This led the researchers to suggest that the burials were conducted in springtime, using colorful and aromatic flowers.
The researchers even found evidence of Natufian bedrock chiseling in the graveyard, demonstrating grave preparation to fit their needs. The Natufians also chiseled a variety of mortars and cupmarks in close vicinity to the graves and on rock exposures on the terrace below the cave. The graves were directly radiocarbon dated. Samples from three different human skeletons were dated to 13,700-11,700 years ago.
“The Natufians lived at a time of many changes – a time when population density was rising and the struggle for land, food and resources was increasing. The establishment of grave yards and unique burial rituals reflects the complexity of the Natufian society. Communal burial sites and elaborate rituals such as funeral ceremonies must have strengthened the sense of solidarity among the community members, and their feeling of unity in the face of other groups”, concluded Prof. Nadel.
The project was led by researchers from the Zinman Institute of Archaelogy at the University of Haifa, with expert partners from the Hebrew University of Jerusalem, the Weizmann Institute, the Max Planck Institute (Germany), The Centre National de la Recherche Scientifique (Paris) and the Anthropology Department at the University of Texas at Austin (USA). The research results were published in the Proceedings of the National Academy of Sciences (United States) journal. The research project in Raqefet cave has been ongoing since 2004, and is largely sponsored by a National Geographic research grant (Committee for Research and Exploration). Additional funds were provided by the Wenner-Gren and CARE Foundations. Raqefet cave is located in a national park (the Israel Nature and Parks Authority). The excavation was conducted under license from the Israel Antiquities Authority. University of Haifa students from the Department of Archeology also participated in the excavations and lab research that followed.
A Wheel Made Of Light Invented
July 5th, 2013
By Alton Parrish.
Light can now be used to achieve ever better control of microparticles and nanoparticles. Researchers at the Max Planck Institute for the Science of Light in Erlangen are now able to use a laser to cause tiny particles to rotate around an axis perpendicular to the light beam – a particle thus rotates like the wheel of a bicycle in its direction of motion.
© Peter Banzer / MPI for the Science of Light
Light can exert incredible forces. According to the rules of quantum mechanics, light is an electromagnetic wave, as well as a stream of photons. Since it has momentum, a transparent particle through which a light beam falls experiences a recoil when the photons leave it. Although the force which a photon exerts in this process is almost infinitesimal, the effect of innumerable light particles in intense and tightly focused laser beams adds up in such a way that objects up to a few micrometres can be held in an optical trap or moved in a specific way. Biologists, for example, use this effect in optical tweezers to fix cells and rotate them at the focus of a microscope. To this effect, scientists working with Gerd Leuchs, Director at the Max Planck Institute for the Science of Light, are now creating new possibilities for them.
The team has created a photonic wheel, i.e. light with purely transverse angular momentum: the electric field of the electromagnetic wave rotates about an axis whose orientation is perpendicular to the direction of motion, just like the axis of a wheel. Until now, physicists have mainly been familiar with light with longitudinal angular momentum where the electric field rotates like a propeller around an axis aligned along the direction of motion. “The possibility that light can have purely transverse angular momentum when averaged over the complete cross-section of the beam had not been realised before,” says Peter Banzer, who made a significant contribution to the discovery.
The light wheel is created in the focal plane of two circularly polarised beams
This is because, as the Erlangen-based physicists have now shown both theoretically and practically, it is indeed possible to generate light with purely transverse angular momentum – and what’s more it is surprisingly easy to do so. “Once it’s down on paper, it looks easy,” says Gerd Leuchs. But somebody has to come up with the idea in the first place. The researchers are now developing this idea using circularly polarised light. A wave of circularly polarised light turns like a screw around the direction of beam propagation and has propeller-like longitudinal angular momentum. Light with circular polarisation can be generated with the aid of a birefringent crystal, for example.
Whether the light wave turns clockwise or anticlockwise depends on the orientation of the crystal. The physicists in Erlangen combined two disks of this material such that one part of the laser beam rotates clockwise and the other part anticlockwise. They then used a lens to focus the two partial beams rotating in opposite directions onto a focal point of the size of the light’s wavelength. “Our theoretical considerations showed that we obtain light with purely transverse angular momentum in the focus – the photonic wheel,” says Peter Banzer.
The light wheel will provide not only biologists with new experimental possibilities for rotating cells under the microscope in three spatial directions in the future. The new way of forming light waves extends the experimental scope in quantum optics and nano-optics as well. Moreover, it should prove useful in nanotechnology, to build nanomixers or other nanomachines, for example. “If we first accelerate particles in an optical trap in a circle and then open the trap, they should hurtle away as they spin, and we could organise a kind of dragster race with nanoparticles,” explains Gerd Leuchs. “In further experiments, we now want to explore the possibilities which the photonic wheel affords us.”
Dr. Peter Banzer