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Wednesday, July 31, 2013

"Lost City" Hints At Life On Moons Of Jupiter And Saturn Say Scientists

How did life on Earth get started? Three new papers co-authored by Mike Russell, a research scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., strengthen the case that Earth's first life began at alkaline hydrothermal vents at the bottom of oceans. Scientists are interested in understanding early life on Earth because if we ever hope to find life on other worlds -- especially icy worlds with subsurface oceans such as Jupiter's moon Europa and Saturn's Enceladus -- we need to know what chemical signatures to look for. 

This image from the floor of the Atlantic Ocean shows a collection of limestone towers known as the "Lost City." Alkaline hydrothermal vents of this type are suggested to be the birthplace of the first living organisms on the ancient Earth. Scientists are interested in understanding early life on Earth because if we ever hope to find life on other worlds - especially icy worlds with subsurface oceans such as Jupiter's moon Europa and Saturn's Enceladus - we need to know what chemical signatures to look for. 
This image from the floor of the Atlantic Ocean shows a collection of limestone towers known as the 'Lost City.'
Image courtesy D. Kelley and M. Elend/University of Washington

Two papers published recently in the journal Philosophical Transactions of the Royal Society B provide more detail on the chemical and precursor metabolic reactions that have to take place to pave the pathway for life. Russell and his co-authors describe how the interactions between the earliest oceans and alkaline hydrothermal fluids likely produced acetate (comparable to vinegar). 

The acetate is a product of methane and hydrogen from the alkaline hydrothermal vents and carbon dioxide dissolved in the surrounding ocean. Once this early chemical pathway was forged, acetate could become the basis of other biological molecules. They also describe how two kinds of "nano-engines" that create organic carbon and polymers -- energy currency of the first cells -- could have been assembled from inorganic minerals.

A paper published in the journal Biochimica et Biophysica Acta analyzes the structural similarity between the most ancient enzymes of life and minerals precipitated at these alkaline vents, an indication that the first life didn't have to invent its first catalysts and engines.

"Our work on alkaline hot springs on the ocean floor makes what we believe is the most plausible case for the origin of the life's building blocks and its energy supply," Russell said. "Our hypothesis is testable, has the right assortment of ingredients and obeys the laws of thermodynamics."

Russell's work was funded by the NASA Astrobiology Institute through the Icy Worlds team based at JPL, a division of the California Institute of Technology, Pasadena. The NASA Astrobiology Institute, based at NASA's Ames Research Center, Moffett Field, Calif., is a partnership among NASA, 15 U.S. teams and 13 international consortia. The Institute is part of NASA's astrobiology program, which supports research into the origin, evolution, distribution and future of life on Earth and the potential for life elsewhere.

Contacts ad sources:
Jia-Rui C. Cook
Jet Propulsion Laboratory

The Forces Controlling Jets On Saturn Moon Enceladus

The intensity of the jets of water ice and organic particles that shoot out from Saturn's moon Enceladus depends on the moon's proximity to the ringed planet, according to data obtained by NASA's Cassini spacecraft.

This set of images from NASA's Cassini mission shows how the gravitational pull of Saturn affects the amount of spray coming from jets at the active moon Enceladus. Enceladus has the most spray when it is farthest away from Saturn in its orbit (inset image on the left) and the least spray when it is closest to Saturn (inset image on the right). 
This set of images from NASA's Cassini mission shows how the gravitational pull of Saturn affects the amount of spray coming from jets at the active moon Enceladus
Image Credit: NASA/JPL-Caltech/University of Arizona/Cornell/SSI

The finding adds to evidence that a liquid water reservoir or ocean lurks under the icy surface of the moon. This is the first clear observation the bright plume emanating from Enceladus' south pole varies predictably. The findings are detailed in a scientific paper in this week's edition of Nature.

"The jets of Enceladus apparently work like adjustable garden hose nozzles," said Matt Hedman, the paper's lead author and a Cassini team scientist based at Cornell University in Ithaca, N.Y. "The nozzles are almost closed when Enceladus is closer to Saturn and are most open when the moon is farthest away. We think this has to do with how Saturn squeezes and releases the moon with its gravity." 

This set of images from NASA's Cassini mission shows the difference in the amount of spray emanating from Saturn's moon Enceladus. The images from Cassini's visual and infrared mapping spectrometer show that Enceladus sprays the most when it is farthest away from Saturn in its orbit (left) and sprays the least when it is closest to Saturn (right). 
This set of images from NASA's Cassini mission shows the difference in the amount of spray emanating from Saturn's moon Enceladus
Image Credit: NASA/JPL-Caltech/University of Arizona/Cornell

Cassini, which has been orbiting Saturn since 2004, discovered the jets that form the plume in 2005. The water ice and organic particles spray out from several narrow fissures nicknamed "tiger stripes."

"The way the jets react so responsively to changing stresses on Enceladus suggests they have their origins in a large body of liquid water," said Christophe Sotin, a co-author and Cassini team member at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Liquid water was key to the development of life on Earth, so these discoveries whet the appetite to know whether life exists everywhere water is present."

For years scientists hypothesized the intensity of the jets likely varied over time, but no one had been able to show they changed in a recognizable pattern. Hedman and colleagues were able to see the changes by examining infrared data of the plume as a whole, obtained by Cassini's visual and infrared mapping spectrometer (VIMS), and looking at data gathered over a long period of time. 

Dramatic plumes, both large and small, spray water ice out from many locations along the famed "tiger stripes" near the south pole of Saturn's moon Enceladus. The tiger stripes are fissures that spray icy particles, water vapor and organic compounds. 
NASA's Cassini spacecraft captured dramatic plumes, both large and small, spray water ice out from many locations along the famed 'tiger stripes' near the south pole of Saturn's moon Enceladus.
Image credit: NASA/JPL/Space Science Institute

The VIMS instrument, which enables the analysis of a wide range of data including the hydrocarbon composition of the surface of another Saturnian moon, Titan, and the seismological signs of Saturn's vibrations in its rings, collected more than 200 images of the Enceladus plume from 2005 to 2012.

These data show the plume was dimmest when the moon was at the closest point in its orbit to Saturn. The plume gradually brightened until Enceladus was at the most distant point, where it was three to four times brighter than the dimmest detection. This is comparable to moving from a dim hallway into a brightly lit office.

Adding the brightness data to previous models of how Saturn squeezes Enceladus, the scientists deduced the stronger gravitational squeeze near the planet reduces the opening of the tiger stripes and the amount of material spraying out. They think the relaxing of Saturn's gravity farther away from planet allows the tiger stripes to be more open and for the spray to escape in larger quantities.

"Cassini's time at Saturn has shown us how active and kaleidoscopic this planet, its rings and its moons are," said Linda Spilker, Cassini project scientist at JPL. "We've come a long way from the placid-looking Saturn that Galileo first spied through his telescope. We hope to learn more about the forces at work here as a microcosm for how our solar system formed." 

Cassini imaging scientists used views like this one to help them identify the source locations for individual jets spurting ice particles, water vapor and trace organic compounds from the surface of Saturn's moon Enceladus. 
Saturn's moon Enceladus
Image credit: NASA/JPL/Space Science Institute

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The VIMS team is based at the University of Arizona in Tucson.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

Contacts ad sources:
Jia-Rui C. Cook
Jet Propulsion Laboratory

Strange Blinking Star Has A Cosmic Hula Hoop

Astronomers using NASA's Spitzer Space Telescope have spotted a young stellar system that "blinks" every 93 days. Called YLW 16A, the system likely consists of three developing stars, two of which are surrounded by a disk of material left over from the star-formation process.

In this artist's impression, a disk of dusty material leftover from star formation girds two young stars like a hula hoop. As the two stars whirl around each other, they periodically peek out from the disk, making the system appear to "blink" every 93 days. 
In this artist's impression, a disk of dusty material leftover from star formation girds two young stars like a hula hoop
Image credit: NASA/JPL-Caltech

As the two inner stars whirl around each other, they periodically peek out from the disk that girds them like a hula hoop. The hoop itself appears to be misaligned from the central star pair, probably due to the disrupting gravitational presence of the third star orbiting at the periphery of the system. The whole system cycles through bright and faint phases, with the central stars playing a sort of cosmic peek-a-boo as the tilted disk twirls around them. It is believed that this disk should go on to spawn planets and the other celestial bodies that make up a solar system.

Spitzer observed infrared light from YLW 16A, emitted by the warmed gas and dust in the disk that still swathes the young stars. Other observations came from the ground-based 2MASS survey, as well as from the NACO instrument at the European Southern Observatory's Very Large Telescope in Chile.

YLW 16A is the fourth example of a star system known to blink in such a manner, and the second in the same star-forming region Rho Ophiuchus. The finding suggests that these systems might be more common than once thought. Blinking star systems with warped disks offer scientists a way to study how planets form in these environments. The planets can orbit one or both of the stars in the binary star system. The famous science fictional planet Tatooine in "Star Wars" orbits two stars, hence its double sunsets. Such worlds are referred to as circumbinary planets. Astronomers can record how light is absorbed by planet-forming disks during the bright and faint phases of blinking stellar systems, which in turn reveals information about the materials that comprise the disk.

"These blinking systems offer natural probes of the binary and circumbinary planet formation process," said Peter Plavchan, a scientist at the NASA Exoplanet Science Institute and Infrared Processing and Analysis Center at the California Institute of Technology, Pasadena, Calif., and lead author of a new paper accepted for publication in Astronomy & Astrophysics.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center. Caltech manages JPL for NASA. For more information about Spitzer, visithttp://spitzer.caltech.edu and http://www.nasa.gov/spitzer .

Contacts ad sources:
Written by Adam Hadhazy
Whitney Clavin
Jet Propulsion Laboratory

Violent Sun Seen By Proba-3 Satellite


ESA’s Sun-watching Proba-2 satellite has been in orbit since November 2009, demonstrating a range of technologies and serving as a platform for scientific observations.

The 130-kg satellite carries two solar monitors. One is SWAP (Sun Watcher using Active Pixel System detector and Image Processing), a small telescope that captures the solar corona at wavelengths corresponding to temperatures of about a million degrees. The image above shows the latest SWAP image, from 30 July.

SWAP images are used to study the origin of solar phenomena, including solar flares and coronal mass ejections – massive eruptions of material into interplanetary space. Both are important sources of space weather, which profoundly affects the environmental conditions in Earth’s magnetosphere, ionosphere and thermosphere.

Space weather is not only of academic interest. In Europe’s economy today, numerous sectors are potentially affected by space weather, ranging from space-based telecommunications, broadcasting, weather services and navigation through to power distribution and terrestrial communications, especially at northern latitudes.

The satellite has been managed since 1 July by ESA’s Space Situational Awareness (SSA) programme, complementing support provided by ESA’s Science directorate for the Proba-2 Science Centre at the Royal Observatory Belgium.

Proba-2 data are used directly by the SSA Space Weather Coordination Centre at SpacePole, Brussels, to generate space weather products and services for a growing number of customers such as satellite operators, telecom and navigation users, and government agencies and research institutes.

Credits: ESA/SWAP PROBA2 science centre

130 Years of Earth Surface Temperatures

How has the surface temperature of Earth been changing? To help find out, Earth scientists collected temperature records from over 1000 weather stations around the globe since 1880, and combined them with modern satellite data.

The movie dramatizes the result showing 130 years of planet-wide temperature changes relative to the local average temperatures in the mid-1900s. In the above global maps, red means warmer and blue means colder


On average, the display demonstrates that the temperature on Earth has increased by nearly one degree Celsius over the past 130 years, and many of the warmest years on record have occurred only recently. Global climate change is of more than passing interest -- it is linked to global weather severity and coastal sea water levels.

Image Credit: GISSNASA

The First Manned Rocket Flight 1633

Lagâri Hasan Çelebi was a legendary Ottoman aviator who, according to an account written by traveler Evliya Çelebi, made a successful manned rocket flight in seventeenth century.

Evliya Çelebi purported that in 1633 Lagari Hasan Çelebi launched in a 7-winged rocket using 50 okka (140 lbs) of gunpowder from Sarayburnu, the point below Topkapı Palace in Istanbul. The flight was said to be undertaken at the time of the birth of Sultan Murad IV's daughter.

Lagâri Hasan Çelebi's rocket flight depicted in a 17th-century engraving.
File:Lagari.jpg
As Evliya Celebi wrote, Lagari proclaimed before launch "O my sultan! Be blessed, I am going to talk to Jesus"; after ascending in the rocket, he landed in the sea, swimming ashore and reporting "O my sultan! Jesus sends his regards to you!;"; he was rewarded by the Sultan with silver and the rank of sipahi in the Ottoman army.

Model of Lagari Hasan Çelebi rocket
Credit: Turkey.com

Evliya Çelebi also wrote of Lagari's brother, Hezarfen Ahmet Celebi, making a flight by glider a year earlier. with levitating.

Istanbul Beneath My Wings is a film about the lives of Hezarfen Ahmet Çelebi, his brother Lagari Hasan Çelebi, and Ottoman society in the early 17th century as witnessed and narrated by Evliya Çelebi.

The legend was addressed in an experiment by the television show MythBusters, on November 11, 2009, in the episode "Crash and Burn"; however, the rocket constructed for the TV show did not adhere closely to Evliya Çelebi's description, and the final design did not attempt to utilize period materials


Rocket technology was first known to Europeans following its use by the Mongols Genghis Khan and Ögedei Khan when they conquered parts of Russia, Eastern, and Central Europe. The Mongolians had acquired the Chinese technology by conquest of the northern part of China and by the subsequent employment of Chinese rocketry experts as mercenaries for the Mongol military. Reports of the Battle of Mohi in the year 1241 describe the use of rocket-like weapons by the Mongols against the Magyars.

Rocket technology also spread to Korea, with the 15th century wheeled hwacha that would launch singijeon rockets. Additionally, the spread of rockets into Europe was also influenced by the Ottomans at the siege of Constantinople in 1453, although it is very likely that the Ottomans themselves were influenced by the Mongol invasions of the previous few centuries. In their history of rockets published on the Internet, NASA says "Rockets appear in Arab literature in 1258 A.D., describing Mongol invaders' use of them on February 15 to capture the city of Baghdad.

First Iron Rockets

In 1792, the first iron-cased rockets were successfully developed and used by Hyder Ali and his son Tipu Sultan, rulers of the Kingdom of Mysore in India against the larger British East India Company forces during the Anglo-Mysore Wars. The British then took an active interest in the technology and developed it further during the 19th century. The Mysore rockets of this period were much more advanced than the British had previously seen, chiefly because of the use of iron tubes for holding the propellant; this enabled higher thrust and longer range for the missile (up to 2 km range). After Tipu's eventual defeat in the Fourth Anglo-Mysore War and the capture of the Mysore iron rockets, they were influential in British rocket development, inspiring the Congreve rocket, which was soon put into use in the Napoleonic Wars.

The First Rockets Developed By The Chinese

Rockets for military and recreational uses date back to at least 13th century China.  The availability of black powder (gunpowder) to propel projectiles was a precursor to experiments as weapons such as bombs, cannon, incendiary fire arrows and rocket-propelled fire arrows. The discovery of gunpowder was probably the product of centuries of alchemical experimentation in which Taoist alchemists were trying to create an elixir of immortality that would allow the person ingesting it to become physically immortal. However, anyone with a wood fire would have observed the acceleration of combustion that accidentally-chosen saltpetre-containing rocks would have produced.
File:Chinese rocket.gif
Exactly when the first flights of rockets occurred is contested. Merely lighting a centimeter-sized solid lump of gunpowder on one side can cause it to move via reaction (even without a nozzle for efficiency), so confinement in a tube and other design refinements may easily have followed for the experimentally-minded with ready access to saltpeter.

A problem for dating the first rocket flight is that Chinese fire arrows can be either arrows with explosives attached, or arrows propelled by gunpowder. There were reports of fire arrows and 'iron pots' that could be heard for 5 leagues (25 km, or 15 miles) when they exploded, causing devastation for a radius of 600 meters (2,000 feet), apparently due to shrapnel. A common claim is that the first recorded use of a rocket in battle was by the Chinese in 1232 against the Mongol hordes at Kai Feng Fu. However, the lowering of iron pots there may have been a way for a besieged army to blow up invaders. A scholarly reference occurs in the Ko Chieh Ching Yuan (The Mirror of Research), states that in 998 AD a man named Tang Fu invented a fire arrow of a new kind having an iron head.

A depiction of the "long serpent" rocket launcher from the 11th century book Wujing Zongyao. The holes in the frame are designed to keep the fire arrows separate.
File:11th century long serpent fire arrow rocket launcher.jpg
Less controversially, one of the earliest devices recorded that used internal-combustion rocket propulsion, was the 'ground-rat,' a type of firework recorded in 1264 as having frightened the Empress-Mother Kung Sheng at a feast held in her honor by her son the Emperor Lizong.

Subsequently, one of the earliest texts to mention the use of rockets was the Huolongjing, written by the Chinese artillery officer Jiao Yu in the mid-14th century. This text also mentioned the use of the first known multistage rocket, the 'fire-dragon issuing from the water' (huo long chu shui), used mostly by the Chinese navy

Tuesday, July 30, 2013

Let There Be Life: New Clues To The Origin Of Life



The chemical components crucial to the start of life on Earth may have primed and protected each other in never-before-realized ways, according to new research led by University of Washington scientists.

It could mean a simpler scenario for how that first spark of life came about on the planet, according to Sarah Keller, UW professor of chemistry, and Roy Black, UW affiliate professor of bioengineering, co-authors of a paper published online July 29 in the Proceedings of the National Academy of Sciences.

A computer graphic of an RNA molecule.
Credit:  Richard Feldmann

Scientists have long thought that life started when the right combination of bases and sugars produced self-replicating ribonucleic acid, or RNA, inside a rudimentary “cell” composed of fatty acids. Under the right conditions, fatty acids naturally form into bag-like structures similar to today’s cell membranes.

In testing one of the fatty acids representative of those found before life began – decanoic acid – the scientists discovered that the four bases in RNA bound more readily to the decanoic acid than did the other seven bases tested.

By concentrating more of the bases and sugar that are the building blocks of RNA, the system would have been primed for the next steps, reactions that led to RNA inside a bag.

“The bag is the easy part. Making RNA from scratch is very hard,” Keller said. “If the parts that come together to make RNA happen to preferentially stick to the surfaces of bags, then everything gets easier.”

The scientists also discovered a second, mutually reinforcing mechanism: The same bases of RNA that preferentially stuck to the fatty acid also protected the bags from disruptive effects of salty seawater. Salt causes the fatty acid bags to clump together instead of remaining as individual “cells.”

The researchers found that several sugars also give protective benefit but the sugar from RNA, ribose, is more effective than glucose or even xylose, a sugar remarkably similar to ribose, except its components are arranged differently.

The ability of the building blocks of RNA to stabilize the fatty acid bags simplifies one part of the puzzle of how life started, Keller said.

“Taken together, these findings yield mutually reinforcing mechanisms of adsorption, concentration and stabilization that could have driven the emergence of primitive cells,” she said.

Black, lead author of the paper, originated the ideas behind the work. A retired biochemist with Amgen Inc., Black contributed funding for the work to Keller’s lab – the work also received National Science Foundation funding – and became a UW affiliate professor volunteering in the Keller lab.

“I think that a pretty common story is that some young hotshot comes to UW to start her or his career and does a risky experiment that uncovers new fundamental science,” Keller said. “Here we have an older hotshot who came to UW at the end of his Amgen career to do a risky experiment that uncovers new fundamental science.

“I think the story also emphasizes that people don’t become scientists just because it is a good job – they do it because they love it,” she said. “Roy worked for a year and a half straight, volunteering his time to UW on something he didn’t get paid for, just for the joy and the curiosity.”

The paper’s other co-authors are Matthew Blosser at the UW, Benjamin Stottrup at Augsburg College in Minneapolis, Ravi Tavakley at the University of Minnesota, and David Deamer at the University of California, Santa Cruz.


Contacts and sources:
By Sandra Hines
Sarah Keller
University of Washington

Scorchingly Uninhabitable Planetary “Runaway Greenhouse” Effect Easier Than Imagined

It might be easier than previously thought for a planet to overheat into the scorchingly uninhabitable “runaway greenhouse” stage, according to new research by astronomers at the University of Washington and the University of Victoria published July 28 in the journal Nature Geoscience.

Venus


In the runaway greenhouse stage, a planet absorbs more solar energy than it can give off to retain equilibrium. As a result, the world overheats, boiling its oceans and filling its atmosphere with steam, which leaves the planet glowing-hot and forever uninhabitable, as Venus is now.

One estimate of the inner edge of a star’s “habitable zone” is where the runaway greenhouse process begins. The habitable zone is that ring of space around a star that’s just right for water to remain in liquid form on an orbiting rocky planet’s surface, thus giving life a chance.

Revisiting this classic planetary science scenario with new computer modeling, the astronomers found a lower thermal radiation threshold for the runaway greenhouse process, meaning that stage may be easier to initiate than had been previously thought.

“The habitable zone becomes much narrower, in the sense that you can no longer get as close to the star as we thought before going into a runaway greenhouse,” said Tyler Robinson, a UW astronomy postdoctoral researcher and second author on the paper. The lead author is Colin Goldblatt of the University of Victoria.


Though further research is called for, the findings could lead to a recalibration of where the habitable zone begins and ends, with some planets having their candidacy as possible habitable worlds revoked.

“These worlds on the very edge got ‘pushed in,’ from our perspective — they are now beyond the runaway greenhouse threshold,” Robinson said.

Subsequent research, the astronomers say, is needed in part because their computer modeling was done in a “single-column, clear-sky model,” or a one-dimensional measure averaged around a planetary sphere that does not account for the atmospheric effect of clouds.

The findings apply to planet Earth as well. As the sun increases in brightness over time, Earth, too, will move into the runaway greenhouse stage — but not for a billion and a half years or so. Still, it inspired the astronomers to write, “As the solar constant increases with time, Earth’s future is analogous to Venus’s past.”

Other co-authors are Kevin J. Zahnle of the NASA Ames Research Center in Moffett Field, Calif.; and David Crisp of the Jet Propulsion Laboratory in Pasadena, Calif.


Contacts and sources:
By Peter Kelley
University of Washington

Pulsating Star Reveals Alien Planet

A team of researchers has devised a way to measure the internal properties of stars—a method that offers more accurate assessments of their orbiting planets.

The research, which appears in Proceedings of the National Academy of Sciences, was conducted by a multi-national team of scientists, including physicists at New York University, Princeton University, and the Max Planck Institute for Solar System Research.

A team of researchers has devised a way to measure the internal properties of stars—a method that offers more accurate assessments of their orbiting planets. The researchers examined HD 52265 and a single planet in the star’s orbit using the COROT space telescope, below, part of a space mission led by the French Space Agency (CNES) in conjunction with the European Space Agency (ESA). Above is an artistic rendering of HD 52265 and its orbiting Jupiter-like planet. 
Pulsating Star Sheds Light on Exoplanet
Image courtesy of MPI for Solar System Research/Mark A. Garlick (www.markgarlick.com).

The researchers examined HD 52265—a star approximately 92 light years away and nearly 20 percent more massive than our Sun. More than a decade ago, scientists identified an exopanet—a planet outside our Solar System—in the star’s orbit. HD 52265, then, served as an ideal model for both measuring stars’ properties and how such properties can shed light on planetary systems.

Previously, scientists inferred stars’ properties, such as radius, mass, and age, by considering observations of their brightness and color. Often these stars’ properties were not known to sufficient accuracy to further characterize the nearby planets.

In the PNAS study, the scientists adopted a new approach to characterize star-planet systems: asteroseismology, which identifies the internal properties of stars by measuring their surface oscillations. Some have compared this approach to seismologists’ use of earthquake oscillations to examine the earth’s interior.

Here, they were able to make several assessments of the star’s traits, including its mass, radius, age, and—for the first time— internal rotation. They used the COROT space telescope, part of a space mission led by the French Space Agency (CNES) in conjunction with the European Space Agency (ESA), to detect tiny fluctuations in the intensity of starlight caused by starquakes. The researchers confirmed the validity of the seismic results by comparing them with independent measurements of related phenomena. These included the motion of dark spots on the star’s surface and the star’s spectroscopic rotational velocity.

Satellite COROT of CNES/ESA 
Pulsating Star Sheds Light on Exoplanet
Image courtesy of CNES/D. Ducros.

Unlike other methods, the technique of asteroseismology returns both the rotation period of the star and the inclination of the rotation axis to the line of sight.

The scientists could then use these findings to make a more definitive determination of an orbiting exoplanet. While it had previously been identified as an exoplanet by other scientists, some raised doubts about this conclusion, positing that it could actually be a brown dwarf—an object too small to be a star and too large to be a planet.

But, armed with the precise calculations yielded by asteroseismology, the researchers on the PNAS study were able to enhance the certainty of the earlier conclusion. Specifically, given the inclination of the rotation axis of HD 52265 and the minimum mass of the nearby exoplanet, the researchers could infer the true mass of the latter—which was calculated to be roughly twice that of our planet Jupiter and therefore too small to be a brown dwarf.

The study’s authors included: Katepalli Sreenivasan, president of Polytechnic Institute of NYU and dean of engineering at NYU; Shravan Hanasoge, an associate research scholar in geosciences at Princeton University and a visiting scholar at NYU’s Courant Institute of Mathematical Sciences; and Laurent Gizon, director of the Max Planck Institute for Solar System Research and a professor at the University of Goettingen in Germany.


Contacts and sources:
New York University

Why Do Black Holes And Galaxies Spin?

Astronomers have found a new way of measuring the spin in supermassive black holes, which could lead to better understanding about how they drive the growth of galaxies. The scientists at Durham University, UK, publish their work in a paper in the Oxford University Press journal Monthly Notices of the Royal Astronomical Society.

The team of astronomers observed a black hole - with a mass 10 million times that of our Sun - at the center of a spiral galaxy 500 million light years from Earth while it was feeding on the surrounding disc of material that fuels its growth and powers its activity.

By viewing optical, ultra-violet and soft x-rays generated by heat as the black hole fed, they were able to measure how far the disc was from the black hole.

This distance depends on black hole spin as a fast spinning black hole pulls the disc in closer to itself, the researchers said. Using the distance between the black hole and the disc, the scientists were able to estimate the spin of the black hole.

The scientists said that understanding spin could lead to greater understanding of galaxy growth over billions of years.

Black holes lie at the centers of almost all galaxies, and can spit out incredibly hot particles at high energies that prevent intergalactic gases from cooling and forming new stars in the outer galaxy. Scientists don't yet understand why the jets are ejected into space, but the Durham experts believe that their power could be linked to the spin of the black hole. This spin is difficult to measure as it only affects the behavior of material really close to the black hole.

An artist’s impression of a supermassive black hole at the centre surrounded by matter flowing onto the black hole in what is termed an accretion disk. Also shown is an outflowing jet of energetic particles, believed to be powered by the black hole's spin.
Image credit: NASA/JPL-Caltech  

Lead researcher Professor Chris Done, in the Department of Physics, at Durham University, said: "We know the black hole in the centre of each galaxy is linked to the galaxy as a whole, which is strange because black holes are tiny in relation to the size of a galaxy. This would be like something the size of a large boulder (10m), influencing something the size of the Earth.

"Understanding this connection between stars in a galaxy and the growth of a black hole, and vice-versa, is the key to understanding how galaxies form throughout cosmic time.

"If a black hole is spinning it drags space and time with it and that drags the accretion disc, containing the black hole's food, closer towards it. This makes the black hole spin faster, a bit like an ice skater doing a pirouette.

"By being able to measure the distance between the black hole and the accretion disc, we believe we can more effectively measure the spin of black holes.

"Because of this, we hope to be able to understand more about the link between black holes and their galaxies."

The Durham scientists were able to measure the spin of the black hole using soft x-ray, optical and ultra-violet images captured by the European Space Agency's XMM-Newton satellite.


Contacts and sources:
Professor Chris Done
Department of Physics
Durham University
Royal Astronomical Society   

First Mini Me Solar System Found, Huge Planet Orbits Tiny Brown Dwarf

 Astronomers have found the first planet orbiting a brown dwarf star.  The system a miniature version of our own solar system,  a kind of Mini Me Solar System. 

Observations of accretion disks around young brown dwarfs have led to the speculation that they may form planetary systems similar to normal stars. While there have been several detections of planetary-mass objects around brown dwarfs (2MASS 1207-3932 and 2MASS 0441-2301), these companions have relatively large mass ratios and projected separations, suggesting that they formed in a manner analogous to stellar binaries

This artist's conception shows the relative size of a hypothetical brown dwarf-planetary system compared to our own solar system. A brown dwarf is a cool or "failed" star, which lacks the mass to ignite and shine like our Sun. NASA's Spitzer Space Telescope set its infrared eyes on an extraordinarily low-mass brown dwarf called OTS 44 and found a swirling disk of planet-building dust. At only 15 times the mass of Jupiter, OTS 44 is the smallest known brown dwarf to host a planet-forming, or protoplanetary, disk.

Image Credit: NASA/JPL-Caltech/T. Pyle (SSC)

Astrophysicists have presented the discovery of a planetary-mass object orbiting a field brown dwarf via gravitational microlensing, OGLE-2012-BLG-0358Lb. The system is a low secondary/primary mass ratio (0.080 +- 0.001), relatively tightly-separated (~0.87 AU) binary composed of a planetary-mass object with 1.9 +- 0.2 Jupiter masses orbiting a brown dwarf with a mass 0.022 M_Sun. The relatively small mass ratio and separation suggest that the companion may have formed in a protoplanetary disk around the brown dwarf host, in a manner analogous to planets.

Brown dwarfs are dwarf stars that are less than one-tenth the mass of our sun.Astrophysical calculations show that such a small star is too small for the "sun ignition" necessary to sustain hydrogen fusion in its core. Such failed stars therefore never light up and therefore constitute a category of warm celestial bodies between stars and large gas planets.

Previously there was no evidence that the formation of brown dwarfs  also had orbiting  planets. However, this deficiency was mainly based on the fact that brown dwarfs are difficult to observe because they are extremely faint and so also any existing planets making identification with the classical methods of planet detection  even more difficult.

For this reason, astronomers used an entirely different search method, called gravitational lensing  to search for planets around a brown dwarf.  Gravitational lensing occurs when a celestial body passes in front of another and its gravity focuses the light of the background object toward Earth. This method has the advantage that it works regardless of the brightness of the body. The method was used by C. Han of the Korean Chungbuk National University and astronomers from the Max Planck Institute for Solar System Research. Their results are current published in "Microlensing Discovery of a Tight, Low Mass-ratio Planetary-mass Object around an Old, Field Brown Dwarf."


The brown dwarf that the researchers currently have examined is about 6,000 light-years away from Earth and resides in the constellation Scorpio.  The astronomers became aware of variations in brightness of the dwarf star for the first time in April 2012 and were able to ensure by further observations, it  was indeed a gravitational lens effect. 

Based on the data the scientists conclude that the brown dwarf is orbited by a planet about has twice the mass of our Jupiter and is less than one astronomical unit (AU = distance Sun-Earth) from the star it orbits. The brown dwarf itself is about ten times larger than its planetary companion. 

 Brown dwarfs (BDs) are sub-stellar objects that are too low in mass to sustain hydrogen fusion reactions in their cores. Although still a matter of debate, the most popular theory about the origin of BDs is that they form via direct collapse similar to stars, perhaps aided by turbulent fragmentation. This theory is supported by observational evidence showing that several medium-sized BDs are girdled by disks of material.  The existence of accretion disks around these failed stars naturally leads to the speculation that BDs may also harbor planetary systems analogous to
those found in abundance around stars. 

There is still debate as to whether the brown dwarf captured it planets or if they formed in a planetary disk around the star.

Dr Evil and Mini Me from the Austin Powers film from which the new solar system derives its comparison.
 
Credit   Austin Powers in Goldmember

Monday, July 29, 2013

Saturn, Titan, Rings, and Haze

This is not a solar eclipse. Pictured is a busy vista of moons and rings taken at Saturn. The large circular object in the center of the image is Titan, the largest moon of Saturn and one of the most intriguing objects in the entire Solar System. The dark spot in the center is the main solid part of the moon. The bright surrounding ring is atmospheric haze above Titan, gas that is scattering sunlight to a camera operating onboard the robotic Cassini spacecraft.

See Explanation.  Clicking on the picture will download
 the highest resolution version available.
Image Credit: Cassini Imaging TeamSSIJPLESANASA

Cutting horizontally across the image are the rings of Saturn, seen nearly edge on. At the lower right of Titan is Enceladus, a small moon of Saturn. Since the image was taken pointing nearly at the Sun, the surfaces of Titan and Enceladus appear in silhouette, and the rings of Saturn appear similar to a photographic negative. Now if you look really really closely at Enceladus, you can see a hint of icy jetsshooting out toward the bottom of the image. It is these jets that inspired future proposals to land on Enceladus, burrow into the ice, and search for signs of extraterrestrial life.

Stargazers Guide To The August Sky: Events Include Perseid Meteor Shower

Backyard stargazers get a monthly guide to the northern hemisphere's skywatching events with "Tonight's Sky." 


August hosts the Perseid meteor shower and some lovely star clusters.  Meteor showers get their names from the constellation in where their radiant is located. 
Perseids come from Perseus, hence the name Perseids

"Tonight's Sky" is produced by HubbleSite.org, online home of the Hubble Space Telescope. This is a recurring show, and you can find more episodes — and other astronomy videos — at HubbleSite.org.

NASA's Chandra Sees Eclipsing Planet In X-rays For First Time

For the first time since exoplanets, or planets around stars other than the sun, were discovered almost 20 years ago, X-ray observations have detected an exoplanet passing in front of its parent star.

An advantageous alignment of a planet and its parent star in the system HD 189733, which is 63 light-years from Earth, enabled NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM Newton Observatory to observe a dip in X-ray intensity as the planet transited the star.

This graphic depicts HD 189733b, the first exoplanet caught passing in front of its parent star in X-rays.

Image Credit: X-ray: NASA/CXC/SAO/K.Poppenhaeger et al; Illustration: NASA

"Thousands of planet candidates have been seen to transit in only optical light," said Katja Poppenhaeger of Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led a new study to be published in the Aug. 10 edition of The Astrophysical Journal. "Finally being able to study one in X-rays is important because it reveals new information about the properties of an exoplanet."

The team used Chandra to observe six transits and data from XMM Newton observations of one.

The planet, known as HD 189733b, is a hot Jupiter, meaning it is similar in size to Jupiter in our solar system but in very close orbit around its star. HD 189733b is more than 30 times closer to its star than Earth is to the sun. It orbits the star once every 2.2 days.

HD 189733b is the closest hot Jupiter to Earth, which makes it a prime target for astronomers who want to learn more about this type of exoplanet and the atmosphere around it. They have used NASA's Kepler space telescope to study it at optical wavelengths, and NASA's Hubble Space Telescope to confirm it is blue in color as a result of the preferential scattering of blue light by silicate particles in its atmosphere.

The study with Chandra and XMM Newton has revealed clues to the size of the planet's atmosphere. The spacecraft saw light decreasing during the transits. The decrease in X-ray light was three times greater than the corresponding decrease in optical light.

"The X-ray data suggest there are extended layers of the planet's atmosphere that are transparent to optical light but opaque to X-rays," said co-author Jurgen Schmitt of Hamburger Sternwarte in Hamburg, Germany. "However, we need more data to confirm this idea."

The researchers also are learning about how the planet and the star can affect one another.

Astronomers have known for about a decade ultraviolet and X-ray radiation from the main star in HD 189733 are evaporating the atmosphere of HD 189733b over time. The authors estimate it is losing 100 million to 600 million kilograms of mass per second. HD 189733b's atmosphere appears to be thinning 25 percent to 65 percent faster than it would be if the planet's atmosphere were smaller.

"The extended atmosphere of this planet makes it a bigger target for high-energy radiation from its star, so more evaporation occurs," said co-author Scott Wolk, also of CfA.

The main star in HD 189733 also has a faint red companion, detected for the first time in X-rays with Chandra. The stars likely formed at the same time, but the main star appears to be 3 billion to 3 1/2 billion years younger than its companion star because it rotates faster, displays higher levels of magnetic activity and is about 30 times brighter in X-rays than its companion.

"This star is not acting its age, and having a big planet as a companion may be the explanation," said Poppenhaeger. "It's possible this hot Jupiter is keeping the star's rotation and magnetic activity high because of tidal forces, making it behave in some ways like a much younger star."

The paper is available online at: http://arxiv.org/abs/1306.2311

Contacts and sources:
Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
NASA

Heavy Cell Phone Use Linked To Increased Risk Of Cancer Says TAU Study

Saliva from heavy cell phone users shows increased risk factors for cancer, says a Tel Aviv University (TAU) researcher

Scientists have long been worried about the possible harmful effects of regular cellular phone use, but so far no study has managed to produce clear results. Currently, cell phones are classified as carcinogenic category 2b — potentially carcinogenic to humans — by the International Agency for Research on Cancer (IARC). A new Tel Aviv University study, though, may bring bad news.


To further explore the relationship between cancer rates and cell phone use, Dr. Yaniv Hamzany of Tel Aviv University's Sackler Faculty of Medicine and the Otolaryngology Head and Neck Surgery Department at the Rabin Medical Center, looked for clues in the saliva of cell phone users. Since the cell phone is placed close to the salivary gland when in use, he and his fellow researchers, including departmental colleagues Profs. Raphael Feinmesser, Thomas Shpitzer and Dr. Gideon Bahar and Prof. Rafi Nagler and Dr. Moshe Gavish of the Technion in Haifa, hypothesized that salivary content could reveal whether there was a connection to developing cancer.

Comparing heavy mobile phone users to non-users, they found that the saliva of heavy users showed indications of higher oxidative stress — a process that damages all aspects of a human cell, including DNA — through the development of toxic peroxide and free radicals. More importantly, it is considered a major risk factor for cancer.

The findings have been reported in the journal Antioxidants and Redox Signaling.

Putting stress on tissues and glands

For the study, the researchers examined the saliva content of 20 heavy-user patients, defined as speaking on their phones for a minimum of eight hours a month. Most participants speak much more, Dr. Hamzany says, as much as 30 to 40 hours a month. Their salivary content was compared to that of a control group, which consisted of deaf patients who either do not use a cell phone, or use the device exclusively for sending text messages and other non-verbal functions.

Compared to the control group, the heavy cell phone users had a significant increase in all salivary oxidative stress measurements studied.

"This suggests that there is considerable oxidative stress on the tissue and glands which are close to the cell phone when in use," he says. The damage caused by oxidative stress is linked to cellular and genetic mutations which cause the development of tumors.

Making the connection

This field of research reflects longstanding concerns about the impact of cell phone use, specifically the effects of radio frequency non-ionizing electromagnetic radiation on human tissue located close to the ear, say the researchers. And although these results don't uncover a conclusive "cause and effect" relationship between cellular phone use and cancer, they add to the building evidence that cell phone use may be harmful in the long term, and point to a new direction for further research.

One potential avenue of future research would be to analyze a person's saliva prior to exposure to a cell phone, and then again after several intense minutes of exposure. This will allow researchers to see if there is an immediate response, such as a rise in molecules that indicate oxidative stress, Dr. Hamzany says.


Contacts and sources: 

Huge Dead Zone In Gulf Of Mexico

NOAA-supported scientists found a large Gulf of Mexico oxygen-free or hypoxic "dead" zone, but not as large as had been predicted. Measuring 5,840 square miles, an area the size of Connecticut, the 2013 Gulf dead zone indicates nutrients from the Mississippi River watershed are continuing to affect the nation's commercial and recreational marine resources in the Gulf.

This map shows the hypoxia area on the Louisiana Gulf of Mexico shelf in 2013.

Credit: LUMCON (Rabalais), NOAA

"A near-record area was expected because of wet spring conditions in the Mississippi watershed and the resultant high river flows which deliver large amounts of nutrients," said Nancy Rabalais, Ph.D. executive director of the Louisiana Universities Marine Consortium (LUMCON), who led the July 21-28 survey cruise. "But nature's wind-mixing events and winds forcing the mass of low oxygen water towards the east resulted in a slightly above average bottom footprint."

Hypoxia is fueled by nutrient runoff from agricultural and other human activities in the watershed. These nutrients stimulate an overgrowth of algae that sinks, decomposes and consumes most of the oxygen needed to support life. Normally the low or no oxygen area is found closer to the Gulf floor as the decaying algae settle towards the bottom. This year researchers found many areas across the Gulf where oxygen conditions were severely low at the bottom and animals normally found at the seabed were swimming at the surface.

This is in contrast to 2012, when drought conditions resulted in the fourth smallest dead zones on record, measuring 2,889 square miles, an area slightly larger than Delaware. The largest previous dead zone was in 2002, encompassing 8,481 square miles. The smallest recorded dead zone measured 15 square miles in 1988. The average size of the dead zone over the past five years has been 5,176 square miles, more than twice the 1,900 square mile goal set by the Gulf of Mexico / Mississippi River Watershed Nutrient Task Force in 2001 and reaffirmed in 2008.

On June 18, NOAA-sponsored forecast models developed by Donald Scavia, Ph.D., University of Michigan, and R. Eugene Turner, Ph.D., Louisiana State University, predicted the Gulf hypoxic zone would range in size from 7,286 to 8,561 square miles.

 
This is a bar graph showing hypoxic trends, task force goals and the last five years' average for period 1985-2013
 
Credit: LUMCON, NOAA

"NOAA's investment in the Gulf of Mexico continues to yield results that confirm the complex dynamics of hypoxia and provide managers and the public with accurate scientific information for managing and restoring the nation's valuable coastal resources," said Robert Magnien, Ph.D., director of NOAA's Center for Sponsored Coastal Ocean Research. "For those who depend upon and enjoy the abundant natural resources of the Gulf of Mexico, it is imperative that we intensify our efforts to reduce nutrient pollution before the ecosystem degrades any further."

This annual measurement provides federal and state agencies working on the 2008 Gulf task force implementation actions with the real consequences of inadequate nutrient pollution management. The task force's actions are set for review this summer.

The hypoxic zone off the coast of Louisiana and Texas forms each summer threatening the ecosystem supporting valuable commercial and recreational Gulf fisheries that in 2011 had a commercial dockside value of $818 million and an estimated 23 million recreational fishing trips. The Gulf task force, in its 2008 report, states that "hypoxia has negative impacts on marine resources." It further states that research on living resources in the Gulf show long term ecological changes in species diversity and a large scale, often rapid change, in the ecosystem's food-web that is both "difficult and impossible to reverse." Additionally, there are numerous annual areas of the Gulf where large scale fish kills occur as a result of hypoxia.

Two surveys conducted in June and early July, one of which was led by a NOAA-supported Texas A&M University team, suggested a large hypoxic zone was forming in the Gulf, though the LUMCON July measurement will be the official one as required of NOAA by the Task Force. NOAA's National Marine Fisheries Service, in conducting its Southeast Monitoring and Assessment Program groundfish surveys, also found large expanses of hypoxia in June-early July. Texas A&M will be conducting a follow-up cruise in mid-August to provide its final seasonal update.


###



Visit the Gulf Hypoxia web site for additional graphics and information concerning this summer's LUMCON research cruise, and previous cruises.

NOAA's National Ocean Service has been funding monitoring and research for the dead zone in the Gulf of Mexico since 1985 and currently oversees the NGOMEX program, the hypoxia research effort for the northern Gulf which is authorized by the Harmful Algal Bloom and Hypoxia Research and Control Act.

The National Centers for Coastal Ocean Science is the coastal science office for NOAA's National Ocean Service.

NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter and our other social media channels.



Contacts and sources:
Ben Sherman
NOAA Headquarters

Ice-Free Arctic Winters Could Explain Amplified Warming During Pliocene

Year-round ice-free conditions across the surface of the Arctic Ocean could explain why the Earth was substantially warmer during the Pliocene Epoch than it is today, despite similar concentrations of carbon dioxide in the atmosphere, according to new research carried out at the University of Colorado Boulder.

The Arctic photographed by NASA satellite
File:Sunny Skies over the Arctic in Late June 2010.jpg
Credit: NASA

In early May, instruments at the Mauna Loa Observatory in Hawaii marked a new record: The concentration of carbon dioxide climbed to 400 parts per million for the first time in modern history.

The last time researchers believe the carbon dioxide concentration in the atmosphere reached 400 ppm—between 3 and 5 million years ago during the Pliocene—the Earth was about 3.5 to 9 degrees Fahrenheit warmer (2 to 5 degrees Celsius) than it is today. During that time period, trees overtook the tundra, sprouting right to the edges of the Arctic Ocean, and the seas swelled, pushing ocean levels 65 to 80 feet higher.

Scientists' understanding of the climate during the Pliocene has largely been pieced together from fossil records preserved in sediments deposited beneath lakes and on the ocean floor.

"When we put 400 ppm carbon dioxide into a model, we don't get as warm a planet as we see when we look at paleorecords from the Pliocene," said Jim White, director of CU-Boulder's Institute of Arctic and Alpine Research and co-author of the new study published online in the journal Palaeogeography, Paleoclimatology, Palaeoecology. "That tells us that there may be something missing in the climate models."

Scientists have proposed several hypotheses in the past to explain the warmer Pliocene climate. One idea, for example, was that the formation of the Isthmus of Panama, the narrow strip of land linking North and South America, could have altered ocean circulations during the Pliocene, forcing warmer waters toward the Arctic. But many of those hypotheses, including the Panama possibility, have not proved viable.

For the new study, led by Ashley Ballantyne, a former CU-Boulder doctoral student who is now an assistant professor of bioclimatology at the University of Montana, the research team decided to see what would happen if they forced the model to assume that the Arctic was free of ice in the winter as well as the summer during the Pliocene. Without these additional parameters, climate models set to emulate atmospheric conditions during the Pliocene show ice-free summers followed by a layer of ice reforming during the sunless winters.

"We tried a simple experiment in which we said, 'We don't know why sea ice might be gone all year round, but let's just make it go away,' " said White, who also is a professor of geological sciences. "And what we found was that we got the right kind of temperature change and we got a dampened seasonal cycle, both of which are things we think we see in the Pliocene."

In the model simulation, year-round ice-free conditions caused warmer conditions in the Arctic because the open water surface allowed for evaporation. Evaporation requires energy, and the water vapor then stored that energy as heat in the atmosphere. The water vapor also created clouds, which trapped heat near the planet's surface.

"Basically, when you take away the sea ice, the Arctic Ocean responds by creating a blanket of water vapor and clouds that keeps the Arctic warmer," White said.

White and his colleagues are now trying to understand what types of conditions could bridge the standard model simulations with the simulations in which ice-free conditions in the Arctic are imposed. If they're successful, computer models would be able to model the transition between a time when ice reformed in the winter to a time when the ocean remained devoid of ice throughout the year.

Such a model also would offer insight into what could happen in our future. Currently, about 70 percent of sea ice disappears during the summertime before reforming in the winter.

"We're trying to understand what happened in the past but with a very keen eye to the future and the present," White said. "The piece that we're looking at in the future is what is going to happen as the Arctic Ocean warms up and becomes more ice-free in the summertime.

"Will we continue to return to an ice-covered Arctic in the wintertime? Or will we start to see some of the feedbacks that now aren't very well represented in our climate models? If we do, that's a big game changer."


Contacts and sources: 
Jim White
University of Colorado at Boulder

Damaging Volcanic Ash Stays Well Beyond Welcome

Researchers study how various sizes, shapes of volcanic ash travel through the atmosphere

Volcanic ash can become a multimillion-dollar nightmare, lingering in the skies, getting into engines and damaging aircraft.



Volcanic ash is known to present hazards to aviation, infrastructure, agriculture, and human and animal health. With the emergence of aviation in the last 50 years as a key component of global travel and transport, the importance of understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance.

Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating the interior parts, thus causing damage and failure. For example, the 2010 Eyjafjallajökull eruption in Iceland was the most disruptive event in aviation history, with billions of dollars of losses to the aviation industry and global economy.

2010 Eyjafjallajökull eruption
File:Eyjafjallajokull volcano plume 2010 04 18.JPG
Credit: Wikipedia

Much of this was unnecessary and better knowledge of the transport of fine ash could minimize such losses in the future. However, present understanding of ash transportation can only account for general air movements, but cannot fully address how much or how long ash remains in the atmosphere, and how much falls out as the ash travels downwind.

Composite map of the volcanic ash cloud spanning 14–25 April 2010
File:Eyjafjallajökull volcanic ash composite.png
Credit: Wikipedia

With support from the National Science Foundation (NSF), volcanologist Dork Sahagian of Lehigh University in Bethlehem, Pa., and his colleagues are learning more about the aerodynamic properties of ash, and how long different sizes and shapes stay in the atmosphere. They use a wind tunnel to study how ash travels in the atmosphere during and after volcanic eruptions. The researchers want to develop ways to predict when and for how long damaging ash will fill the skies, and when it's safe to fly again.


Contacts and sources:
Miles O'Brien, Science Nation Correspondent
Ann Kellan, Science Nation Producer

Sunday, July 28, 2013

After 40,000 Years Head Reattached To Ancient Ice Age Sculpture

Researchers from the University of Tübingen have successfully reattached the newly discovered head of a prehistoric mammoth ivory figurine discovered in 1931. The head was found during renewed excavations at Vogelherd Cave, site of the original dig in 1931. The recent excavations, between 2005 and 2012, have yielded a number of important finds.

A lion figurine carved from mammoth ivory, now with refitted head. Found at Vogelherd Cave in southwestern Germany. Approx. 40,000 years old.
Photo: H. Jensen. Copyright University of Tübingen

 The discovery of this ivory head helps to complete a figurine which now can be recognized as a lion – and demonstrates that it is possible to reassemble often fragmentary figurines from the earlier excavation. The new discovery is presented in the 2013 edition of the journal “Archäologische Ausgrabungen in Baden-Württemberg”.

Side view of the lion figurine. Mammoth ivory, found at Vogelherd Cave in southwestern Germany. Approx. 40,000 years old. 
 
Photo H. Jensen. Copyright University of Tübingen

Vogelherd Cave is located in the Lone Valley of southwestern Germany and is by far the richest of the four caves in the region that have produced examples of the earliest figurative art, dating as far back as 40,000 years ago. Overall, Vogelherd Cave has yielded more than two dozen figurines and fragments of figurines. 

Re-excavation of the sediments from Vogelherd Cave 
Photo: M. Zeidi. Copyright University of Tübingen

While the work of fitting together thousands of small fragments of mammoth ivory from Vogelherd is just beginning, the remarkable lion figurine, now with its head, forms an important part of the display of the earliest art at the Museum of the University of Tübingen (MUT) in Hohentübingen Castle.

Professor Nicholas Conard and his excavation assistant Mohsen Zeidi today presented the new discovery and discussed its scientific importance, after which the find rejoined the permanent exhibit at MUT. Prof. Ernst Seidl of MUT commented on the importance of the Vogelherd discoveries for the University and the region.
Prof. Gustav Riek in front of Vogelherd Cave during excavations in the summer of 1931. 
Photo: Copyright University of Tübingen

Contacts and sources:
Prof. Nicholas Conard Ph.D.
University of Tübingen
Institute of Prehistory and Medieval Archaeology
Senckenberg Center for Human Evolution and Palaeoenvironment Tübingen

Prof. Dr. Ernst Seidl
University of Tübingen MUT
http://www.unimuseum.de

Drunken Geniuses: Sharp as a Tack, Drunk as a Skunk

Drunken Geniuses: Sharp as a Tack, Drunk as a Skunk
Image source: www.bestmastersdegrees.com


Contacts and sources:
Pamela Brooke

Hoag's Object: A Strange Ring Galaxy

Explanation: Is this one galaxy or two? This question came to light in 1950 when astronomer Art Hoag chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older. Between the two is a gap that appears almost completely dark.

How Hoag's Object formed remains unknown, although similar objects have now been identified and collectively labeled as a form of ring galaxy.
See Explanation.  Clicking on the picture will download
 the highest resolution version available.
Genesis hypotheses include a galaxy collision billions of years ago and the gravitational effect of a central bar that has since vanished. The above photo taken by the Hubble Space Telescope in July 2001 revealed unprecedented details of Hoag's Object. More recent observations in radio waves indicate that Hoag's Object has not accreted a smaller galaxy in the past billion years. Hoag's Object spans about 100,000 light years and lies about 600 million light years away toward the constellation of the Snake (Serpens). Coincidentally, visible in the gap (at about one o'clock) is yet another ring galaxy

Image Credit: Credit: R. Lucas (STScI/AURA), Hubble Heritage Team, NASA

Hubble Eyes A Mysterious Old Spiral

This striking cosmic whirl is the center of galaxy NGC 524, as seen with the NASA/ESA Hubble Space Telescope. This galaxy is located in the constellation of Pisces, some 90 million light-years from Earth.
thin lines of lace-like dark filaments spiral many times around a distant pale white blur
Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

NGC 524 is a lenticular galaxy. Lenticular galaxies are believed to be an intermediate state in galactic evolution — they are neither elliptical nor spiral. Spirals are middle-aged galaxies with vast, pin wheeling arms that contain millions of stars. Along with these stars are large clouds of gas and dust that, when dense enough, are the nurseries where new stars are born. When all the gas is either depleted or lost into space, the arms gradually fade away and the spiral shape begins to weaken. At the end of this process, what remains is a lenticular galaxy — a bright disc full of old, red stars surrounded by what little gas and dust the galaxy has managed to cling on to.

This image shows the shape of NGC 524 in detail, formed by the remaining gas surrounding the galaxy’s central bulge. Observations of this galaxy have revealed that it maintains some spiral-like motion, explaining its intricate structure.

Source: NASA


Saturday, July 27, 2013

One Giant Leap For Unmanned-Kind, FAA Approves Two New Drones For Domestic Flyovers



The Federal Aviation Administration has issued restricted category type certificates to a pair of unmanned aircraft systems (UAS), a milestone that will lead to the first approved commercial UAS operations later this summer.

The newly certified UAS—Insitu’s Scan Eagle X200 and AeroVironment’s PUMA—are “small” UAS weighing less than 55 pounds. Each is about 4 ½ feet long, with wingspans of ten and nine feet, respectively.

When Insitu first supported the U.S. Marine Corps in 2004 combat operations, ScanEagle offered a choice of either industry-leading electro-optic (EO) or long-wave infrared (LWIR) imagers. Over the years, Insitu added to that. Today the field-configurable NightEagle™ variant of ScanEagle carries a mid-wave infrared imager (MWIR) for daylight-quality infrared imagery, and a dual-bay option lets customers carry both EO and LWIR imagers at once.
File:ScanEagle UAV catapult launcher 2005-04-16.jpg

The major advantage of having type-certificated UAS models available is that they can be used commercially. The Scan Eagle and PUMA received Restricted Category type certificates that permit aerial surveillance. Until now, obtaining an experimental airworthiness certificate – which specifically excludes commercial operations—was the only way the private sector could operate UAS in the nation’s airspace. 

AeroVironment’s PUMA
File:RQ20A-130304-M-DE426-001 crop.jpg

 Previous military acceptance of the Scan Eagle and PUMA UAS designs allowed the FAA to issue the Restricted Category type certificates.

A major energy company plans to fly the ScanEagle off the Alaska coast in international waters starting in August. Plans for the initial ship-launched flights include surveys of ocean ice floes and migrating whales in Arctic oil exploration areas. The PUMA is expected to support emergency response crews for oil spill monitoring and wildlife surveillance over the Beaufort Sea.

Issuing the type certificates is an important step toward the FAA’s goal of integrating UAS into the nation’s airspace. These flights will also meet requirements in the FAA Modernization and Reform Act of 2012 that define Arctic operational areas and include a mandate to increase Arctic UAS commercial operations.

Friday, July 26, 2013

Extinct Ancient Ape Did Not Walk Like a Human, Says Study

According to a new study, led by University of Texas at Austin anthropologists Gabrielle A. Russo and Liza Shapiro, the 9- to 7-million-year-old ape from Italy did not, in fact, walk habitually on two legs. The findings refute a long body of evidence, suggesting that Oreopithecus had the capabilities for bipedal (moving on two legs) walking.

Oreopithecus 
File:Oreopithecus bambolii 1.JPG
Credit: Wikipedia

The study, published in a forthcoming issue of the Journal of Human Evolution, confirms that anatomical features related to habitual upright, two-legged walking remain exclusively associated with humans and their fossil ancestors.

“Our findings offer new insight into the Oreopithecus locomotor debate,” says Russo, who is currently a postdoctoral research fellow at Northeast Ohio Medical University. “While it’s certainly possible that Oreopithecus walked on two legs to some extent, as apes are known to employ short bouts of this activity, an increasing amount of anatomical evidence clearly demonstrates that it didn’t do so habitually.”

As part of the study, the researchers analyzed the fossil ape to see whether it possessed lower spine anatomy consistent with bipedal walking. They compared measurements of its lumbar vertebrae (lower back) and sacrum (a triangular bone at the base of the spine) to those of modern humans, fossil hominins (extinct bipedal human ancestors), and a sample of mammals that commonly move around in trees, including apes, sloths and an extinct lemur.

The lower spine serves as a good basis for testing the habitual bipedal locomotion hypothesis because human lumbar vertebrae and sacra exhibit distinct features that facilitate the transmission of body weight for habitual bipedalism, says Russo.

According to the findings, the anatomy of Oreopithecus lumbar vertebrae and sacrum is unlike that of humans, and more similar to apes, indicating that it is incompatible with the functional demands of walking upright as a human does.

“The lower spine of humans is highly specialized for habitual bipedalism, and is therefore a key region for assessing whether this uniquely human form of locomotion was present in Oreopithecus,” says Shapiro, a professor of anthropology. “Previous debate on the locomotor behavior of Oreopithecus had focused on the anatomy of the limbs and pelvis, but no one had reassessed the controversial claim that its lower back was human-like.”


Contacts and sources:
Gabrielle A. Russo
University of Texas 

Bee Armageddon: Cause Determined And Its Far Worse Than Anyone Expected

Commercial honey bees used to pollinate crops are exposed to a wide variety of agricultural chemicals, including common fungicides which impair the bees’ ability to fight off a potentially lethal parasite, according to a new study by researchers at the University of Maryland and the U.S. Department of Agriculture.

File:Honeybee-cooling cropped.jpg
Credit: Wikipedia

The study, published July 24 in the online journal PLOS ONE, is the first analysis of real-world conditions encountered by honey bees as their hives pollinate a wide range of crops, from apples to watermelons.

The researchers collected pollen from honey bee hives in fields from Delaware to Maine. They analyzed the samples to find out which flowering plants were the bees’ main pollen sources and what agricultural chemicals were commingled with the pollen. The researchers fed the pesticide-laden pollen samples to healthy bees, which were then tested for their ability to resist infection with Nosema ceranae – a parasite of adult honey bees that has been linked to a lethal phenomenon known as colony collapse disorder.

On average, the pollen samples contained 9 different agricultural chemicals, including fungicides, insecticides, herbicides and miticides. Sublethal levels of multiple agricultural chemicals were present in every sample, with one sample containing 21 different pesticides. Pesticides found most frequently in the bees’ pollen were the fungicide chlorothalonil, used on apples and other crops, and the insecticide fluvalinate, used by beekeepers to control Varroa mites, common honey bee pests.

In the study’s most surprising result, bees that were fed the collected pollen samples containing chlorothonatil were nearly three times more likely to be infected by Nosema than bees that were not exposed to these chemicals, said Jeff Pettis, research leader of the USDA’s Bee Research Laboratory and the study’s lead author. The miticides used to control Varroa mites also harmed the bees’ ability to withstand parasitic infection.

Credit: www.sott.net

Beekeepers know they are making a trade-off when they use miticides, said University of Maryland researcher Dennis vanEngelsdorp, the study’s senior author. The chemicals compromise bees’ immune systems, but the damage is less than it would be if mites were left unchecked. But the study’s finding that common fungicides can be harmful at real world dosages is new, and points to a gap in existing regulations, he said.

“We don’t think of fungicides as having a negative effect on bees, because they’re not designed to kill insects,” vanEngelsdorp said. Federal regulations restrict the use of insecticides while pollinating insects are foraging, he said, “but there are no such restrictions on fungicides, so you’ll often see fungicide applications going on while bees are foraging on the crop. This finding suggests that we have to reconsider that policy.”

In an unexpected finding, most of the crops that the bees were pollinating appeared to provide their hives with little nourishment. Honey bees gather pollen to take to their hives and feed their young. But when the researchers collected pollen from bees foraging on native North American crops such as blueberries and watermelon, they found the pollen came from other flowering plants in the area, not from the crops. This is probably because honey bees, which evolved in the Old World, are not efficient at collecting pollen from New World crops, even though they can pollinate these crops.

The study’s findings are not directly related to colony collapse disorder, the still-unexplained phenomenon in which entire honey bee colonies suddenly die. However, the researchers said the results shed light on the many factors that are interacting to stress honey bee populations.

Contacts and sources:
Heather Dewar
University of Maryland

Antarctica Melting Much Faster Than Expected, See Timelapse Imagery

For the first time, scientists have documented an acceleration in the melt rate of permafrost, or ground ice, in a section of Antarctica where the ice had been considered stable. The melt rates are comparable with the Arctic, where accelerated melting of permafrost has become a regularly recurring phenomenon, and the change could offer a preview of melting permafrost in other parts of a warming Antarctic continent.

Research team member Jim O'Connor of the USGS inspects a block of ice calved off the Garwood Valley ice cliff.
Photo by Joseph Levy, University of Texas Institute for Geophysics.

Tracking data from Garwood Valley in the McMurdo Dry Valleys region of Antarctica, Joseph Levy, a research associate at The University of Texas at Austin’s Institute for Geophysics, shows that melt rates accelerated consistently from 2001 to 2012, rising to about 10 times the valley’s historical average for the present geologic epoch, as documented in the July 24 edition of Scientific Reports.

Scientists had previously considered the region’s ground ice to be in equilibrium, meaning its seasonal melting and refreezing did not, over time, diminish the valley’s overall mass of ground ice.

Instead, Levy documented through LIDAR and time-lapse photography a rapid retreat of ground ice in Garwood Valley, similar to the lower rates of permafrost melt observed in the coastal Arctic and Tibet.

Garwood Valley lies within the McMurdo Dry Valleys region of Antarctica.
 Image: Landsat Image Mosaic of Antarctica.

“The big tell here is that the ice is vanishing — it’s melting faster each time we measure,” said Levy, who noted that there are no signs in the geologic record that the valley’s ground ice has retreated similarly in the past. “This is a dramatic shift from recent history.”

Ground ice is more prevalent in the Arctic than in Antarctica, where glaciers and ice sheets dominate the landscape. In contrast to glaciers and ice sheets, which sit on the ground, ground ice sits in the ground, mixed with frozen soil or buried under layers of sediment. Antarctica’s Dry Valleys contain some of the continent’s largest stretches of ground ice, along the coast of the Ross Sea.

After Levy and colleagues noted visible effects of ground ice retreat in Garwood Valley, they began to monitor the valley, combining time-lapse photography and weather-station data at 15-minute intervals to create a detailed view of the conditions under which the ice, a relict from the last ice age, is being lost.

Rising temperatures do not account for the increased melting in Garwood Valley. The Dry Valleys overall experienced a well-documented cooling trend from 1986 to 2000, followed by stabilized temperatures to the present.

Rather, Levy and his co-authors attribute the melting to an increase in radiation from sunlight stemming from changes in weather patterns that have resulted in an increase in the amount of sunlight reaching the ground.

Timelapse imagery of ice loss in Garwood Valley, Nov. 2010 to Jan. 2012. The period represents the start and end of one summer season (Nov. 2010-Jan. 2011) followed by the end of the next season (Jan. 2012). The views were generated with biannual LiDAR scans of the valley.

Credit: The University of Texas at Austin, Institute for Geophysics.

Sunlight tends to bounce off the white, reflective surfaces of glaciers and ice sheets, but the darker surfaces of dirty ground ice can absorb greater amounts of solar radiation. Thick layers of sediment tend to insulate deeply buried ground ice from sunlight and inhibit melting. But thin sediment layers have the opposite effect, effectively cooking the nearby ice and accelerating melt rates.

As the ground ice melts, the frozen landscape sinks and buckles, creating what scientists describe as “retrogressive thaw slumps.” An acceleration in the prevalence of such slumps has been well documented in the Arctic and other permafrost regions, but not in Antarctica.

Levy’s research shows that even under the stable temperature conditions of the Dry Valleys, recent increases in sunlight are leading to Arctic-like slump conditions.

If Antarctica warms as predicted during the coming century, the melting and slumping could become that much more dramatic as warmer air temperatures combine with sunlight-driven melting to thaw ground ice even more quickly.

Ground ice is not the major component of Antarctica’s vast reserves of frozen water, but there are major expanses of ground ice in the Dry Valleys, the Antarctic Peninsula and the continent’s ice-free islands.

Garwood Valley could tell the story of what will happen in these “coastal thaw zones,” says Levy.

“There's a lot of buried ice in these low-elevation coastal regions, and it is primed to melt.”

Co-authors on the paper were Andrew Fountain of Portland State University, James Dickson and James Head of Brown University, Marianne Okal of UNAVCO, David Marchant of Boston University and Jaclyn Watters of The University of Texas at Austin.

The research was supported by a grant from the National Science Foundation.

Contacts and sources:
Joseph Levy
University of Texas Institute for Geophysics
Jackson School of Geosciences