Space telescope reveals weird star cluster conundrum

NGC 2024 is a star cluster found in the center of the Flame Nebula, approximately 1,400 light-years from Earth. This observation combines X-ray and infrared data from NASA's Chandra and Spitzer space telescopes, respectively.NASA

We thought we had star formation mechanisms pinned down, but according to new observations of two star clusters, it seems our understanding of how stars are born is less than stellar.

PHOTOS: Herschel’s Coolest Infrared Hotshots

When zooming in on the young star clusters of NGC 2024 (in the center of the Flame Nebula) and the Orion Nebula Cluster, NASA’s Chandra X-ray Observatory teamed up with infrared telescopes to take a census of star ages. Conventional thinking suggests that stars closest to the center of a given star cluster should be the oldest and the youngest stars can be found around the edges.

However, to their surprise, astronomers have discovered that the opposite is true.

“Our findings are counterintuitive,” said Konstantin Getman of Penn State University, lead scientist of this new study. “It means we need to think harder and come up with more ideas of how stars like our sun are formed.”

It is thought that stars form after the gravitational collapse of vast clouds of dust and gas, or nebulae. The densest material can be found at the nebula’s center and, as the thinking goes, will be ripe for the first stars in that nebula to appear. After the first stars in the nebula’s center burst to life with fusion burning cores, the leftover gases in the less dense portions of the nebula will generate stars later on.

ANALYSIS: Orion’s ‘Death Stars’ Exterminate Baby Planets

After using Chandra data to gauge the stars’ masses and brightnesses, and then combining that data with infrared observations, stellar ages could be calculated. In the case of NGC 2024, the researchers noticed that the stars in the cluster’s core were 200,000 years old, but the stars on the outer edges were much older — around 1.5 million years old. Likewise, the Orion Nebula Cluster hosts stars in its core that are 1.2 million years old and the ones around the edge were 2 million years old.

This discovery has caught astrophysicists on the hop and may turn our understanding of star forming regions on its head.

“A key conclusion from our study is we can reject the basic model where clusters form from the inside out,” said coauthor Eric Feigelson, also of Penn State. “So we need to consider more complex models that are now emerging from star formation studies.”

So what’s going on? Is our understanding of stellar mechanics really that wrong? Not necessarily, but star cluster evolution models will certainly need some tweaking.

NEWS: Spitzer Sheds Light on Colony of Baby Stars

The researchers have several possible answers to the conundrum. First, it could be that there’s simply more gas in the center of the star-forming nebula that allows stars to be born long after stars have finished forming in the depleted edges of the cluster. That would make it appear that there are older stars at the edges than in the core. Secondly, stars that formed first in the cluster’s center have more time to gravitationally interact with other stars, causing them to be slingshotted to the cluster’s edges, leaving younger stars behind.

Thirdly, the young stars could be formed in the cluster’s center by filaments of gas and dust that fall into the center of the cluster. This could be envisaged as a sort of “conveyer belt” effect where older stars are replaced in the core by new stars being created by in-falling material.

Whether one of these theories is the correct one (or whether it’s a combination of all three) remains to be seen, but this is certainly a reminder that the physics of star formation is far from being fully understood; it is an exciting and evolving field of study that turns up its fair share of surprises.

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Grotesque Mummy Head Reveals Advanced Medieval Science

In the second century, an ethnically Greek Roman named Galen became doctor to the gladiators. His glimpses into the human body via these warriors' wounds, combined with much more systematic dissections of animals, became the basis of Islamic and European medicine for centuries.

Galen's texts wouldn't be challenged for anatomical supremacy until the Renaissance, when human dissections — often in public — surged in popularity. But doctors in medieval Europe weren't as idle as it may seem, as a new analysis of the oldest-known preserved human dissection in Europe reveals.

The gruesome specimen, now in a private collection, consists of a human head and shoulders with the top of the skull and brain removed. Rodent nibbles and insect larvae trails mar the face. The arteries are filled with a red "metal wax" compound that helped preserve the body. [Gallery: Historic Images of Human Anatomy]

The preparation of the specimen was surprisingly advanced. Radiocarbon dating puts the age of the body between A.D. 1200 and A.D.1280, an era once considered part of Europe's anti-scientific "Dark Ages." In fact, said study researcher Philippe Charlier, a physician and forensic scientist at University Hospital R. Poincare in France, the new specimen suggests surprising anatomical expertise during this time period.   

"It's state-of-the-art," Charlier told LiveScience. "I suppose that the preparator did not do this just one time, but several times, to be so good at this."

Myths of the middle ages

Historians in the 1800s referred to the Dark Ages as a time of illiteracy and barbarianism, generally pinpointing the time period as between the fall of the Roman Empire and somewhere in the Middle Ages. To some, the Dark Ages didn't end until the 1400s, at the advent of the Renaissance.

But modern historians see the Middle Ages quite differently. That's because continued scholarship has found that the medieval period wasn't so ignorant after all. [Busted! 10 Medieval Myths]

"There was considerable scientific progress in the later Middle Ages, in particular from the 13th century onward," said James Hannam, an historian and author of "The Genesis of Science: How the Christian Middle Ages Launched the Scientific Revolution" (Regnery Publishing, 2011).

For centuries, the advancements of the Middle Ages were forgotten, Hannam told LiveScience. In the 16th and 17th centuries, it became an "intellectual fad," he said, for thinkers to cite ancient Greek and Roman sources rather than scientists of the Middle Ages. In some cases, this involved straight-up fudging. Renaissance mathematician Copernicus, for example, took some of his thinking on the motion of the Earth from Jean Buridan, a French priest who lived between about 1300 and 1358, Hannam said. But Copernicus credited the ancient Roman poet Virgil as his inspiration.

Much of this selective memory stemmed from anti-Catholic feelings by Protestants, who split from the church in the 1500s.

As a result, "there was lots of propaganda about how the Catholic Church had been holding back human progress, and it was great that we were all Protestants now," Hannam said. 

Anatomical dark ages?

From this anti-Catholic sentiment arose a great many myths, such as the idea that everyone believed the world to be flat until Christopher Columbus sailed to the Americas. ("They thought nothing of the sort," Hannam said.)

Similarly, Renaissance propagandists spread the rumor that the Medieval Christian church banned autopsy and human dissection, holding back medical progress.

In fact, Hannam said, many societies have banned or limited the carving up of human corpses, from the ancient Greeks and Romans to early Europeans (that's why Galen was stuck dissecting animals and peering into gladiator wounds). But autopsies and dissection were not under a blanket church ban in the Middle Ages. In fact, the church sometimes ordered autopsies, often for the purpose of looking for signs of holiness in the body of a supposedly saintly person.

The first example of one of these "holy autopsies" came in 1308, when nuns conducted a dissection of the body of Chiara of Montefalco, an abbess who would be canonized as a saint in 1881. The nuns reported finding a tiny crucifix in the abbess' heart, as well as three gallstones in her gallbladder, which they saw as symbolic of the Holy Trinity.

Other autopsies were entirely secular. In 1286, an Italian physician conducted autopsies in order to pinpoint the origin of an epidemic, according to Charlier and his colleagues.

Some of the belief that the church frowned on autopsies may have come from a misinterpretation of a papal edict from 1299, in which the Pope forbade the boiling of the bones of dead Crusaders. That practice ensured Crusaders' bones could be shipped back home for burial, but the Pope declared the soldiers should be buried where they fell.

"That was interpreted in the 19th century as actually being a stricture against human dissection, which would have surprised the Pope," Hannam said.

Well-studied head

While more investigation of the body was going on in the Middle Ages than previously realized, the 1200s remain the "dark ages" in the sense that little is known about human anatomical dissections during this time period, Charlier said. When he and his colleagues began examining the head-and-shoulders specimen, they suspected it would be from the 1400s or 1500s.

"We did not think it was so antique," Charlier said.

But radiocarbon dating put the specimen firmly in the 1200s, making it the oldest European anatomical preparation known. Most surprisingly, Charlier said, the veins and arteries are filled with a mixture of beeswax, lime and cinnabar mercury. This would have helped preserve the body as well as give the circulatory system some color, as cinnabar mercury has a red tint.  

Thus, the man's body was not simply dissected and tossed away; it was preserved, possibly for continued medical education, Charlier said. The man's identity, however, is forever lost. He could have been a prisoner, an institutionalized person, or perhaps a pauper whose body was never claimed, the researchers write this month in the journal Archives of Medical Science.

The specimen, which is in private hands, is set to go on display at the Parisian Museum of the History of Medicine, Charlier said.  

"This is really interesting from a historical and archaeological point of view," Charlier said, adding, "We really have a lack of skeletons and anthropological pieces."

Email Stephanie Pappas or follow her @sipappas. Follow LiveScience on Twitter @livescience, on Facebook or Google+. Original article on LiveScience.com.

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Milky Way Radiation Reveals Itself to Distant NASA Probes (SPACE.com)

Decades after NASA's Voyager spacecraft began hurtling toward interstellar space, the twin probes are still shedding light on the universe, now by offering an unprecedented view of our own galaxy.

As they roam ever outward to the edge of the solar system, the two Voyager spacecraft are providing the first glimpse of Milky Way radiation that scientists have already seen coming from other galaxies. The data could lead to a better understanding of star formation, including the mystery surrounding the earliest stars in the universe, researchers said.

NASA launched the two Voyager spacecraft in 1977 to explore our solar system's giant planets and to study the electrically charged solar wind streaming from the sun. The probes far exceeded the expectations of mission planners, and to this day, they continue to beam back data.

The Voyagers are now providing us with the first glimpse of a critical type of ultraviolet radiation from our galaxy known as the Lyman-alpha line. This is the brightest band of light shed by hydrogen, the most abundant element in the universe.

Studying the Lyman-alpha line can offer many insights into cosmic phenomena, such as star formation, the electrically charged environments in which the atmospheres of young planets evolve, and the shocked gas in interstellar space. [Photos from NASA's Voyager 1 and 2 Probes]

Astronomers have seen Lyman-alpha rays from other galaxies, helping them peer into the universe's early history. However, we have never seen ones from our own galaxy, because our sun essentially blinds our view.

Specifically, ultraviolet rays from our sun get scattered around by hydrogen entering our solar system from interstellar space. This leads to a haze that blinds us to Lyman-alpha rays from elsewhere in our galaxy. We can detect other galaxies' Lyman-alpha rays because they have shifted into longer optical and infrared wavelengths — ones that no longer get scattered by this hydrogen — as their galaxies rush away from us. This is similar to how ambulance sirens grow lower in pitch as the vehicle drives farther away.

Now Voyager 1 and 2 are far enough away from this ultraviolet haze for them to get a clear view of the Milky Way's Lyman-alpha rays.

"It is like beginning to see small candles within a brightly lit room," study lead author Rosine Lallement, a space scientist and astronomer at the Paris Observatory in Meudon, France, told SPACE.com.

The spacecraft have confirmed that most of these newfound rays appear to come from star-forming regions, as astronomers expected. Future study of the Milky Way's Lyman-alpha rays could help us better understand those from other galaxies, researchers added.

"This radiation traces where young hot stars are being born — therefore, knowing the amount of emitted Lyman-alpha radiation from a galaxy corresponds to the rate at which stars are being born," Lallement said. "A major goal is to detect the first apparition of stars in the young universe, so detecting Lyman-alpha from the most-distant ones and correctly interpreting the signal is one of the major challenges."

Ironically, just as the Voyager probes are getting their best views of these Milky Way rays, their ability to see them is failing. Due to lack of power, the ultraviolet spectrometer on Voyager 2 has been switched off, and that same instrument on Voyager 1 could get turned off soon as well.

Still, NASA's New Horizons spacecraft, which is currently on its way to Pluto, might soon be able to monitor these rays as well.

Lallement and her colleagues detailed their findings online in the Dec. 1 issue of the journal Science.

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New Photo of Moon's North Pole Reveals Spiral Illusion (SPACE.com)

Here's a view of the moon you'll never see from Earth.

NASA scientists created this mosaic by stitching together 983 images of the moon's North Pole region taken by the Lunar Reconnaissance Orbiter (LRO). The LRO robotic probe, which has been mapping the moon from above since 2009, has acquired thousands of wide-angle camera shots of its polar regions. [Photo of the moon's north pole]

Because the mottled moon only tilts on its access at an angle of 1.54 degrees (as compared to Earth's 23.5 degree tilt) some of its surface never sees sunlight. One goal of the LRO mission is to identify these regions of permanent shadow. The probe took the photos in the composite image above at the height of summer in our satellite's northern hemisphere — the time when the pole is best illuminated. Thus, dark areas, such as those along the inside rims of deep craters and the immediate vicinity of the pole, are probably permanently dark.

The craters around the pole appear to spiral out from it. According to Mark Robinson, principle investigator of the LRO team based at Arizona State University, this is an optical illusion. [The Most Amazing Optical Illusions (and How They Work)]

"Imagine a series of very narrow pie slices collected 12 times each day, one after another," Robinson told Life's Little Mysteries, a sister site to SPACE.com. "It takes roughly 360 slices to fill in the whole pie. Each day the sun direction is progressing around the moon, thus the direction that the sun is striking the surface changes. So the shadow directions slowly progress around the moon, thus leading to the illusion."

This story was provided by Life's Little Mysteries, a sister site to SPACE.com. Follow Natalie Wolchover on Twitter @nattyover. Follow Life's Little Mysteries on Twitter @llmysteries, then join us on Facebook.

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Radar reveals extent of buried ancient Egyptian city

CAIRO (AP) — An Austrian archaeological team has used radar imaging to determine the extent of the ruins of the one time 3,500-year-old capital of Egypt's foreign occupiers, said the antiquities department Sunday.Egypt was ruled for a century from 1664-1569 B.C. by the Hyksos, a warrior people from Asia, possibly Semitic in origin, whose summer capital was in the northern Delta area.

Irene Mueller, the head of the Austrian team, said the main purpose of the project is to determine how far the underground city extends.

The radar imaging showed the outlines of streets, houses and temples underneath the green farm fields and modern town of Tel al-Dabaa.

Archaeology chief Zahi Hawass said in the statement that such noninvasive techniques are the best way to define the extent of the site. Egypt's Delta is densely populated and heavily farmed, making extensive excavation difficult, unlike in southern Egypt with its more famous desert tombs and temples.

The Austrian team of archaeologists has been working on the site since 1975.

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Tiny camera reveals inside of ancient Mayan tomb

The inside of a tomb of a Mayan ruler, that has been sealed for 1,500 years, is seen in southern Mexico, in this handout photograph released by Mexico's National Institute of Anthropology and History (INAH) June 23, 2011. A tiny remote-controlled camera was used to peer inside the tomb, revealing red frescoes, pottery and pieces of a funerary shroud made of jade and mother of pearl. The tomb was discovered in 1999 inside a pyramid among the ruins of the Mayan city of Palenque in the hills of the southern Mexican state of Chiapas. But until now archeologists had not been able to access the vault believed to hold the remains of a Mayan ruler who lived between AD 431 and 550, the National Institute of Anthropology and History said in a release on Thursday.

Credit: Reuters/INAH/Handout

MEXICO CITY | Thu Jun 23, 2011 10:23pm EDT

MEXICO CITY (Reuters) - A tiny remote-controlled camera peered inside the tomb of a Mayan ruler that has been sealed for 1,500 years, revealing red frescoes, pottery and pieces of a funerary shroud made of jade and mother of pearl.

The tomb was discovered in 1999 inside a pyramid among the ruins of the Mayan city of Palenque in the hills of the southern Mexican state of Chiapas.

But until now archeologists had not been able to access the vault believed to hold the remains of a Mayan ruler who lived between AD 431 and 550, the National Institute of Anthropology and History said in a release on Thursday.

By dropping the small camera 16 feet deep through a small hole at the top of the pyramid, researchers were able to get the first view of the intact tomb.

"The characteristics of the funeral site show that the bones could belong to a sacred ruler from Palenque, probably one of the founders of a dynasty," said archeologist Martha Cuevas.

The tomb's walls are painted in a rich red with paintings of Mayan figures. The Mayans flourished between AD 250-900 and Palenque is one of the most important Mayan archeological sites.

(Reporting by Rachel Uranga, writing by Cyntia Barrera, editing by Anthony Boadle)

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NASA Spacecraft Reveals Mercury's Surprising 'Personality' (SPACE.com)

A NASA spacecraft circling Mercury is returning spectacular photos of the planet — and delivering some tantalizing surprises about the tiny, scorched world.

On March 17, NASA's Messenger probe became the first spacecraft ever to orbit Mercury. Since then, Messenger has already snapped more than 20,000 pictures and made observations that could help unlock long-standing mysteries of the solar system's innermost planet, researchers announced at a press conference today (June 16).

"We had many Latest Messenger Photos of Mercury]

Mercury has 'personality'

Messenger is photographing every inch of Mercury's surface from orbit, and some of its early pictures have revealed huge expanses of volcanic deposits near the planet's north pole. These features were detected by Messenger and NASA's Mariner 10 probe on previous Mercury flybys, but the new observations map them out in greater detail. [Infographic: The Messenger Mission]

"Now we're seeing their full extent for the first time," said Messenger scientist Brett Denevi of Johns Hopkins University's Applied Physics Laboratory (APL). And that extent is impressive; the northern volcanic plains cover 1.54 million square miles (4 million square kilometers) — nearly half the size of the continental United States.

These new observations help confirm that volcanism has substantially shaped Mercury's crust and surface for much of its history, researchers said.

Messenger has been scrutinizing Mercury with more than just its camera gear. The probe's X-ray spectrometer, for example, has already discovered that the planet's surface is made of different stuff than the moon, which is dominated by feldspar-rich rock.

The spectrometer has also detected surprisingly high levels of sulfur at the planet's surface, which could help scientists understand the nature of Mercury's origin and volcanism, researchers said.

So far, the spacecraft's observations are putting the lie to the notion that Mercury is similar to the moon. In fact, the early returns indicate that it's also very different than the other terrestrial planets, in ways that are only just beginning to come clear.

"Mercury really is a world in and of its own," said Messenger project scientist Ralph McNutt of APL. "Just like the Earth, it's got its own personality."

Water ice on Mercury?

Messenger is using another one of its seven instruments, a laser altimeter, to map out Mercury's topography. The spacecraft has already taken more than 2 million laser-ranging readings, revealing the planet's geological features in great detail.

"We're seeing the broad shape of the planet for the first time," Solomon said.

One of the many questions Messenger hopes to answer is whether or not Mercury harbors water ice on its surface. That might not seem very likely, since average surface temperatures on the planet can top 842 degrees Fahrenheit (450 degrees Celsius). However, Earth-based radar observations from 20 years ago suggest large amounts of ice may lurk in permanently shadowed craters at its poles.

And the early results from Messenger, which is mapping those craters with its altimeter, support this idea. Thus far, the probe's data indicate that some polar craters may be so deep that their floors are in permanent shadow. Whether they actually contain ice will have to be confirmed by different instruments, researchers said.

"Stay tuned," Solomon said. "The very first scientific test of that hypothesis using Messenger data from orbit has passed with flying colors."

Magnetic fields and more

Messenger has also been investigating the nature of Mercury's global magnetic field, which is of interest partly because Mercury is the only rocky planet in the solar system to possess one, other than Earth.

Mercury's magnetic field was thought to be more or less a miniature version of Earth's, researchers said. But Messenger's readings are showing that's not the case.

For starters, Mercury's magnetic field is asymmetrical, with its magnetic equator lying significantly north of the planet's geographic equator. This surprising geometry suggests that Mercury's south polar region is much more exposed than the north to bombardment by charged particles from the sun.

Scientists don't fully understand the import of many of Messenger's early findings. The probe is just 25 percent of the way through its planned one-year science mission around Mercury, after all.

"There's a lot more to come," McNutt said. "All I can say is to keep following us — the best is yet to be."

A long trip to Mercury

The $446 million Messenger mission — whose name is short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging — launched in August 2004.  It is designed to map Mercury fully for the first time and help answer several key questions about the planet. [The Greatest Mysteries of Mercury]

Mission scientists hope to learn, for example, why Mercury is so much denser than the other rocky planets. And they want to gain insights into how the planet's core is structured, the nature of its global magnetic field and other aspects of Mercury's composition and history. 

Scientists hope all of this information will lead to an increased understanding of how our solar system — and solar systems in general — formed and evolved, researchers have said.

The spacecraft is now in an extremely oblong, or elliptical, orbit that brings it within 124 miles (200 kilometers) of Mercury at the closest point and retreats to more than 9,300 miles (15,000 km) away at the farthest point. Its orbital science mission is designed to last for 12 months.

While Messenger is the first mission ever to orbit Mercury, it is not the first spacecraft to visit the planet. NASA's Mariner 10 spacecraft flew by the planet three times in the mid-1970s. Messenger itself also made three flybys of the planet on its long, circuitous space journey, snapping photos all the while.

You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

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Radar reveals extent of buried ancient Egyptian city

CAIRO (AP) — An Austrian archaeological team has used radar imaging to determine the extent of the ruins of the one time 3,500-year-old capital of Egypt's foreign occupiers, said the antiquities department Sunday.Egypt was ruled for a century from 1664-1569 B.C. by the Hyksos, a warrior people from Asia, possibly Semitic in origin, whose summer capital was in the northern Delta area.

Irene Mueller, the head of the Austrian team, said the main purpose of the project is to determine how far the underground city extends.

The radar imaging showed the outlines of streets, houses and temples underneath the green farm fields and modern town of Tel al-Dabaa.

Archaeology chief Zahi Hawass said in the statement that such noninvasive techniques are the best way to define the extent of the site. Egypt's Delta is densely populated and heavily farmed, making extensive excavation difficult, unlike in southern Egypt with its more famous desert tombs and temples.

The Austrian team of archaeologists has been working on the site since 1975.

Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more.

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