Walrus Bones Found in Old London Burial Ground

During a recent excavation beneath the streets of London, archaeologists found a total of 1,500 human bodies, many buried hastily in a wave of epidemics that struck the quickly expanding city more than 150 years ago.

In one coffin, archaeologists came across a grisly mix of bones from at least eight human bodies, many of them cut up and showing evidence of autopsy. But nine of the bone fragments were decidedly not human. They were walrus.

"It came as something of a shock," said Phil Emery, an archaeologist with a company called Ramboll UK, who led the excavation. The nine bone fragments came from a Pacific walrus that was likely 13 feet long, Emery told LiveScience.

Behold the walrus

The bodies came from the old burial ground of St Pancras Church, and were interred there between 1822 and 1854, Emery said. During this time, London cemeteries were overwhelmed by the dead from a series of cholera, typhus and smallpox epidemics; the church and its burial ground, once outside greater London, have recently been engulfed by the burgeoning metropolis, he added.

Before 1822, the cemetery was characterized by small plots, as seen in most ordinary burial grounds, Emery said. But thereafter, ceremony fell to the wayside as the cemetery was overwhelmed — plots were replaced with mass graves, he said.

From 1822 to 1854, a total of 44,000 burials took place there, Emery said. "Under such conditions, one can understand that standards of decency and hygiene were difficult to maintain, to put it lightly," he explained.

Blame the med students

But how did a tusked beast the weight of a small car make its way from the North Pacific to a cemetery in foggy London? Emery and his team can only guess how the walrus was brought there from its native lands, but they suspect the animal was dissected by curious medical students.

That hunch comes from the fact that several of the bones within the coffin showed signs of dissection, such as skull fragments with holes drilled in them, he said. In 1832, within the range of dates when the bones would have been laid to rest there, a law was passed that allowed medical students to legally dissect cadavers, Emery said. Before that, cadavers were obtained from the gallows, or illegally snatched via grave robbery, he added.

The walrus limbs were likely dissected as a matter of curiosity, Emery said, perhaps as an exercise in comparative anatomy.

'Sea monster'

At the time, "very few Londoners would have seen one of these alive," Emery said. "It was the archetypal sea monster, often depicted on early sea maps as a sort of exotic beast. The animal would have captured peoples' imaginations."

Read more at Discovery News

Earth's Hellish Potential

It used to be that Venus was the only planet in the solar system thought capable of a runaway greenhouse effect — hence its furnace-like inhabitability. But new modeling suggests that Earth is perfectly capable of falling into a self-reinforcing heating cycle as well. Luckily, not even humanity’s greenhouse gas emissions are enough to trigger that planet-killing scenario on our home planet.

Just to review, a runaway greenhouse effect is where a planet gets stuck in a vicious cycle of heating and can’t stop. We’re not talking the anthropogenic kind of heating, of a few degrees Celsius. That kind of greenhouse heating is bad enough, but a runaway greenhouse effect would dry up the oceans and turn Earth into an autoclave: sterilized of life.

It’s long been thought that such a deadly cycle of heating was not possible on Earth because Earth is just far enough away from the Sun that our planet’s intake of solar energy is too low. But a paper in the July 28 issue of Nature Geoscience suggests Earth is close enough to the Sun after all.

Computer modelling by the University of Victoria’s Colin Goldblatt and colleagues shows that a planet that gets the same amount of solar irradiation as Earth could go either way: to a stable climate or a Venus-like disaster.

The numerical model calculated the balance between solar radiation taken in and thermal radiation released back into space by Earth’s surface and atmosphere. They found that with a lot more greenhouse gases and steamy air Earth could morph into another Venus.

“A runaway greenhouse could in theory be triggered by increased greenhouse forcing, but anthropogenic emissions are probably insufficient,” the researchers write.

On the other hand, they do hope that their work helps to identify exoplanets that are in habitable zones of their stars, and are likely to have avoided runaway greenhouses, since, those are the best places to expect life.

From Discovery News

Rocks Can Restore Our Climate ... After 300,000 Years

A study of a global warming event that happened 93 million years ago suggests that the Earth can recover from high carbon dioxide emissions faster than thought, but that this process takes around 300,000 years after emissions decline.Scientists from Oxford University studied rocks from locations including Beachy Head, near Eastbourne, and South Ferriby, North Lincolnshire, to investigate how chemical weathering of rocks 'rebalanced' the climate after vast amounts of carbon dioxide (CO2) were emitted during more than 10,000 years of volcanic eruptions.

In chemical weathering CO2 from the atmosphere dissolved in rainwater reacts with rocks such as basalt or granite, dissolving them so that this atmospheric carbon then flows into the oceans, where a large proportion is 'trapped' in the bodies of marine organisms.

The team tested the idea that, as CO2 warms the planet, the reactions involved in chemical weathering speed up, causing more CO2 to be 'locked away', until, if CO2 emissions decline, the climate begins to cool again. The Oxford team looked at evidence from the 'Ocean Anoxic Event 2' in the Late Cretaceous when volcanic activity spewed around 10 gigatonnes of CO2 into the atmosphere every year for over 10,000 years. The researchers found that during this period chemical weathering increased, locking away more CO2 as the world warmed and enabling the Earth to stabilise to a cooler climate within 300,000 years, up to four times faster than previously thought.

A report of the research is published in Nature Geoscience.

'Looking at this event is rather like imagining what the Earth would be like if humans disappeared tomorrow,' said Dr Philip Pogge von Strandmann of Oxford University's Department of Earth Sciences, who led the research. 'Volcanic CO2 emissions in this period are similar to, if slightly slower than, current manmade emissions so that we can imagine a scenario in which, after human CO2 emissions ceased, the planet's climate would start to recover and cool down. The bad news is that it's likely this would take around 300,000 years.'

Reconstructing a record of past chemical weathering is challenging because of how plants and animals take carbon out of the environment. To get around this the team used a recently-developed technique involving studying lithium isotopes in marine limestone (this lithium could only come from weathering and is not changed by biological organisms).

The Ocean Anoxic Event 2 is believed to have been caused by a massive increase in volcanic activity in one of three regions: the Caribbean, Madagascar, or the Solomon Islands. The event saw the temperature of seawater around the equator warm by about 3 degrees Celsius. It is thought that this warming caused around 53% of marine species to go extinct. Animals like turtles, fish, and ammonites were amongst those severely affected.

'Everyone remembers the mass extinction of land animals caused by the K-T meteorite impact 30 million years later, thought to be responsible for the demise of the dinosaurs, but in many ways this was just as devastating for marine life,' said Dr Pogge von Strandmann. 'Whilst nutrients from weathering caused a population boom of some species near the surface of the oceans, it also led to a loss of oxygen to the deeper ocean, killing off over half of all marine species and creating a 'dead zone' of decaying animals and plants. It's a scenario we wouldn't want to see repeated today.

Read more at Science Daily

Removing Complexity Layers from the Universe's Creation

Complicated statistical behaviour observed in complex systems such as early universe can often be understood if it is broken down into simpler ones. Two physicists, Petr Jizba (currently affiliated with the Czech Technical University in Prague), and Fabio Scardigli (now working at Kyoto University in Japan), have just published results in the European Physical Journal C pertaining to theoretical predictions of such cosmological systems' dynamics.

Their work focuses on complex dynamical systems whose statistical behaviour can be explained in terms of a superposition of simpler underlying dynamics. They found that the combination of two cornerstones of contemporary physics -- namely Einstein's special relativity and quantum-mechanical dynamics -- is mathematically identical to a complex dynamical system described by two interlocked processes operating at different energy scales. The combined dynamic obeys Einstein's special relativity even though neither of the two underlying dynamics does. This implies that Einstein's special relativity might well be an emergent concept and suggests that it would be worthwhile to further develop Einstein's insights to take into account the quantum structure of space and time.

To model the double process in question, the authors consider quantum mechanical dynamics in a background space consisting of a number of small crystal-like domains varying in size and composition, known as polycrystalline space. There, particles exhibit an analogous motion to pollen grains in water, referred to as Brownian motion. The observed relativistic dynamics then comes solely from a particular grain distribution in the polycrystalline space. In the cosmological context such distribution might form during the early universe's formation.

Finally, the authors' new interpretation focuses on the interaction of a quantum particle with gravity, that, according to Einstein's general relativity, can be understood as propagation in curved space-time. The non-existence of the relativistic dynamics on the basic level of the description leads to a natural mechanism for the formation of asymmetry between particles and anti-particles. When coupled with an inflationary cosmology, the authors' approach predicts that a charge asymmetry should have been produced at ultra-minute fractions of seconds after the Big Bang. This prediction is in agreement with constraints born out of recent cosmological observations.

From Science Daily

Mysterious Hum Driving People Around the World Crazy

It creeps in slowly in the dark of night, and once inside, it almost never goes away.

It's known as the Hum, a steady, droning sound that's heard in places as disparate as Taos, N.M.; Bristol, England; and Largs, Scotland.

But what causes the Hum, and why it only affects a small percentage of the population in certain areas, remain a mystery, despite a number of scientific investigations.

Reports started trickling in during the 1950s from people who had never heard anything unusual before; suddenly, they were bedeviled by an annoying, low-frequency humming, throbbing or rumbling sound.

The cases seem to have several factors in common: Generally, the Hum is only heard indoors, and it's louder at night than during the day. It's also more common in rural or suburban environments; reports of a hum are rare in urban areas, probably because of the steady background noise in crowded cities.

Who hears the Hum?

Only about 2 percent of the people living in any given Hum-prone area can hear the sound, and most of them are ages 55 to 70, according to a 2003 study by acoustical consultant Geoff Leventhall of Surrey, England.

Most of the people who hear the Hum (sometimes referred to as "hearers" or "hummers") describe the sound as similar to a diesel engine idling nearby. And the Hum has driven virtually every one of them to the point of despair.

"It's a kind of torture; sometimes, you just want to scream," retiree Katie Jacques of Leeds, England, told the BBC. Leeds is one of several places in Great Britain where the Hum has recently appeared.

"It's worst at night," Jacques said. "It's hard to get off to sleep because I hear this throbbing sound in the background … You're tossing and turning, and you get more and more agitated about it."

Being dismissed as crackpots or whiners only exacerbates the distress for these complainants, most of whom have perfectly normal hearing. Sufferers complain of headaches, nausea, dizziness, nosebleeds and sleep disturbances. At least one suicide in the United Kingdom has been blamed on the Hum, the BBC reports.

The Hum zones

Bristol, England, was one of the first places on Earth where the Hum was reported. In the 1970s, about 800 people in the coastal city reported hearing a steady thrumming sound, which was eventually blamed on vehicular traffic and local factories working 24-hour shifts.

Another famous hum occurs near Taos, N.M. Starting in spring 1991, residents of the area complained of a low-level rumbling noise. A team of researchers from Los Alamos National Laboratory, the University of New Mexico, Sandia National Laboratories and other regional experts were unable to identify the source of the sound.

Windsor, Ontario, is another Hum hotspot. Researchers from the University of Windsor and Western University in London, Ontario, were recently given a grant to analyze the Windsor Hum and determine its cause.

Researchers also have been investigating the Hum in Bondi, a seaside area of Sydney, Australia, for several years, to no avail. "It sends people around here crazy — all you can do is put music on to block it out. Some people leave fans on," one resident told the Daily Telegraph.

Back in the United States, the Kokomo Hum was isolated in a 2003 study financed by the Indiana city's municipal government. The investigation revealed that two industrial sites — one a Daimler Chrysler plant — were producing noise at specific frequencies. Despite noise-abatement measures, some residents continue to complain of the Hum.

What causes the Hum?

Most researchers investigating the Hum express some confidence that the phenomenon is real, and not the result of mass hysteria or hearers' hypochondria (or extraterrestrials beaming signals to Earth from their spaceships).

As in the case of the Kokomo Hum, industrial equipment is usually the first suspected source of the Hum. In one instance, Leventhall was able to trace the noise to a neighboring building's central heating unit.

Other suspected sources include high-pressure gas lines, electrical power lines, wireless communication devices or other sources. But only in a few cases has a Hum been linked to a mechanical or electrical source.

There's some speculation that the Hum could be the result of low-frequency electromagnetic radiation, audible only to some people. And there are verified cases in which individuals have particular sensitivities to signals outside the normal range of human hearing.

Medical experts are quick to point out that tinnitus (the perception of sound when no external noise is present) is a likely cause, but repeated testing has found that many hearers have normal hearing and no occurrences of tinnitus.

Environmental factors have also been blamed, including seismic activity such as microseisms — very faint, low-frequency earth tremors that can be generated by the action of ocean waves.

Other hypotheses, including military experiments and submarine communications, have yet to bear any fruit. For now, hearers of the Hum have to resort to white-noise machines and other devices to reduce or eliminate the annoying noise.

Read more at Discovery News

Sharp-Eyed Solar Telescope Snaps First Photos

Last month, a new telescope was launched into orbit to help scientists solve a long-standing mystery about why the sun’s atmosphere, called the corona, is nearly 1,000 times hotter than its surface.

There is no answer yet, but the first images from the Interface Region Imaging Spectrograph, or IRIS, observatory show the sun is more complicated than scientists imagined.

IRIS has 10 times the resolving power as previous solar telescopes, so the team, headed by Lockheed Martin’s Alan Title, knew they would be getting more detailed images and data. But they didn’t expect to see so many dynamic regions especially in what appeared to be relatively quiescent sections of the sun. And they don’t yet know what it means.

“We’ve seen this data only for less than a week and most of that time we’ve been trying to understand just how we ought to run this instrument,” Title, with Lockheed’s Advanced Technology Center in Palo Alto, Calif., told reporters on a conference call Thursday.

“I’m not brash enough to tell you what new and exciting things there are, but there are hints that people are very excited about,” he added.

“We’re now seeing a lot more structure than we anticipated that we would see. There are some things in these images that we had expected, but there are others that are completely new to us,” Title said.

The 4-foot long, 450-pound telescope was launched on June 27 for what is expected to be a two-year mission. Its first images were released on Thursday.

Read more at Discovery News

Medieval Mansion Found at U.K. Construction Site

It sounds like a case for Sherlock Holmes: a 900-year-old medieval manor mysteriously vanishes, only to be uncovered later by British archaeologists.

The ancient site has been stripped of its materials except for the foundation -- and there is no record of it ever existing.

Got chills? So do the archaeologists who discovered it.

"This is a significant find and therefore very exciting, particularly as there are no documentary records that such a site ever existed here," said Wessex Archaeology's senior buildings archaeologist Bob Davis, who participated in the excavation.

Excavators from the company arrived on April 8 at the site in Longforth Farm in Wellington, Somerset, a small agricultural county in southwest England. They planned to perform an archaeological dig prior to the construction of a housing development by Bloor Homes, as required by the Somerset Country Council.

They had no way of knowing their routine excavation would reveal a hidden series of buildings dating to the 12th through 14th century.

"This sort of thing turning up -- a large medieval building of such high status without any surviving historical records -- it's exceptionally mysterious and strange," senior historic environment officer for the Somerset Country Council Steve Membery told ThisIsCornwall.co.uk.

"It looks as if it's a previously unrecorded, undocumented, high-status, ecclesiastical manor house," Davis told the British paper. "Such things are as rare as hen's teeth."

All that remains from what appears to have been an impressive, affluent mansion is the stone foundation and a few leftover artifacts. It is expected that antiquities thieves would steal valuables from the site, but archaeologists are literally picking at scraps to find out what happened to the doors, windows, stones and other materials that are to be found in a large manor.

They were able to uncover stunningly glazed ceramic roof tiles and carefully decorated floor tiles, however, suggesting the buildings were of high status, perhaps used for religious services.

But much like the American colony of Roanoke, N.C., whomever used the buildings left no trace or record of their existence; they appear to have simply vanished.

"We do not yet know who owned or used the buildings," community and education officer for Wessex Archaeology Laura Joyner told FoxNews.com. "They appear to form a distinct complex of buildings."

The most recent discovery has helped shed some light on the use for some of the structures.

According to Wessex Archaeology, the two tiles pictured below confirm the existence of private chambers and a possible chapel at the Longforth Farm site.

The tile on the left includes a checkered agent or shield motif, which possibly relates to the family name of St. Barbe, a medieval aristocratic British family. Centuries later, Ursula St. Barbe, the daughter of Henry St. Barbe from Somerset with the same last name, was a lady in the court of Queen Elizabeth I of England in the late 1500s.

The second tile, similar to one found at Glastonbury Abbey, is a depiction of a helmeted King Richard I (1189-1199) on horseback, charging his enemy. The tile "would originally have had an opposing tile showing Saladin, Sultan of Egypt, also in a symbolic combat pose," according to Wessex Archaeology. "These two great adversaries were involved in the Third Crusade (1189–1192) and are often depicted together on this type of floor tile."

Based on the artifacts, the owners of the buildings were wealthy and powerful. So what happened to those medieval VIPs?

Read more at Discovery News

Viking Jewelry Unearthed in Denmark

Several pieces of Viking jewelry, some of which contain gold, have been uncovered at a farm site in Denmark that dates as far back as 1,300 years.

Although the Vikings have a popular reputation as being raiders, they were also farmers, traders and explorers, and the craftsmanship seen in this jewelry demonstrates their artistic skills.

Archaeologists working with volunteers used metal detectors to find the jewelry in different spots throughout a farmstead on Zealand, the largest island in Denmark. The remains of the site, which is now called Vestervang, date from the late seventh to the early 11th centuries.

Finding such lavish goods at such a modest farm site poses a puzzle, the archaeologists said. The reason why the farm site would hold such treasure may lie in a legendary site located nearby.

Heart-shaped animal head

The "most spectacular" example is 2.9 inches (73 millimeters) long and shows an image of a heart-shaped animal head with rounded ears and circular eyes, writes archaeologist Ole Thirup Kastholm, of the Roskilde Museum, in a paper published in the most recent edition of the Danish Journal of Archaeology. The piece, made of copper alloy, may be part of a necklace.

"The neck is covered by a beadlike chain," Kastholm writes. "Above the creatures forelegs, there are marked elbow joints and three-fingered paws or feet, which awkwardly grasp backwards to what might be hind legs or wings." The object probably had three similar images originally, but only one survives.

In addition to the animal image, the item, possibly a pendant, also shows three masked figures, each with a "drooping moustache." A "circular mark is seen between the eyebrows and above this, two ears or horns emerge, giving the humanlike mask an animal character," Kastholm writes.

He said that the animal image itself seems to be anthropomorphic, something not unusual in Viking age art. "Some of these anthropomorphic pictures, though, might be seen as representations of 'shamanic' actions, i.e. as mediators between the 'real' world and the 'other' world," Kastholm wrote in an email to LiveScience. He can't say for sure who would have worn it, but it "certainly (was) a person with connections to the elite milieu of the Viking age."

A golden Christian mystery

Another mysterious piece of jewelry found at Vestervang depicts a Christian cross and appears to have been created in continental Europe sometime between A.D. 500 and 750, predating the Viking-age farm site.

"The decoration consists of a central wheel cross in relief, with inlaid gold pressed into a waffle form. The waffle gold is in some areas covered with transparent red glass or semiprecious stones and forming an equal-armed cross," writes Kastholm in the paper.

How the artifact arrived at a pre-Christian Viking-age farm site is a mystery. A Christian traveler may have brought it to Vestervang, or a non-Christian person at the site may have acquired it through exchange. The item would have been used as a brooch, and Kastholm said a female of "high rank" perhaps wore it on her dress.

It "tells us about close relations and networks between Southern Scandinavia and the European continent in late Iron Age, before the time of Christianization," Kastholm wrote in the email.

Rich jewelry at a modest site

These discoveries leave researchers with a mystery. What is such rich jewelry doing at a modest agricultural settlement?

The answer may lie in a legendary site, named Lejre, which is located about 6 miles (10 kilometers) south-southeast of Vestervang, no more than three hours away by foot and boat.

"Legend has it that this was the place where the first Danish dynasty, the Scyldings, had its royal seat," writes Tom Christensen, also of the Roskilde Museum, in an article published in the book "Settlement and Coastal Research in the Southern North Sea Region" (Verlag Marie Leidorf, 2010). He notes that some members of this dynasty even appeared in the famous poem "Beowulf."

Archaeological research has revealed that Lejre appears to be a rich site. In 1850, a hoard consisting of "four silver vessels, a whetstone, a weight, a necklace and a disk-shaped silver ingot" was found in the nearby hills, Christensen noted. A monument 282 feet (86 meters) long made of rocks arranged in the shape of a ship was also reconstructed in later excavations.

The presence of this elite site close to Vestervang may explain the presence of the newly found rich jewelry, Kastholm writes. In the 1960s, there was vast residential development in the area of Vestervang, but maps that predate the development show two villages near the site with "Karleby" in their name, something that may signify that the area was given to retainers of Lejre's ruler.

"The old Scandinavian term karl, corresponding with the old English ceorl, refers to a member of the king's professional warrior escort, the hirð," Kastholm writes in the journal article.

Together, the rich jewelry finds at Vestervang, the site's proximity to Lejre and the presence of two nearby villages with the names "Karleby" reveal what life may have been like at Vestervang.

Read more at Discovery News

Bee Decline Threatens Entire Ecosystems

The widely-reported decline of bee populations worldwide is wreaking havoc in certain ecosystems, particularly since it is now known that bees can be very fickle when it comes to pollination.

A recent study reveals that if bees loyal to one plant species are removed from the system, other bee species may continue to pollinate those plants, but sometimes with the wrong pollen. Researchers Berry Brosi, Ph.D, an assistant professor at Emory University, and Heather Briggs, a graduate student at University of California, observed what happens when a main-pollinating species of bees is removed from its chosen floral target.

“We knew that scientific work done indicates plant communities are largely resilient to losing pollinator species,” Brosi said from his study site at Rocky Mountain Biological Lab in Crested Butte, CO. “If you lose one species the plant has backup, so there is redundancy built into the system.”

But much of these results came from computer models that simulated the activity in an ecosystem, Brosi said. “We wanted to see if this would hold up in real life. We hypothesized that the picture might not be quite as rosy as the computer models indicated.”

They were right. “When there are a lot of different species of bees, competition makes each species become more specialized. We thought there’s a chance when we lose a main pollinator species that remaining species might begin to generalize a little bit more and forage on more different kinds of flowers and that could be bad from a plant perspective. Plants need pollen from exact same species of plant to thrive. If a pollinator is visiting many different plant species it can transport the wrong kind of pollen to a plant.”

Using handheld nets, Brosi and Briggs removed the most abundant species of bumblebees from a meadow of larkspur plants that sat within 20 plots of wildflowers, 20 meters each. Tracking all the steps of the pollination process, they waited to see if other bumblebee species from nearby plots would properly pollinate the larkspur.

“We wanted to see how much they focused on one plant species, or if they showed floral infidelity,” said Brosi. “We looked at the pollen they carried and transferred to the flowers, and finally we looked at seed production.”

Despite computer models to the contrary, they found across all steps of pollination there was more movement between different plant species in the remaining bees. “Bees carried multiple pollen types and deposed them to the larkspur,” Brosi said. Unfortunately, this caused seed production to decrease by one-third.

The results signal two possible broad implications, Brosi said. “First, we can’t necessarily trust the results of computer simulations about pollinator species. Yes, plants still have backup, but the quality of the interaction with other species of bees goes down, which is even more reason to be concerned about loss of bee species.

Second, we’ve shown that biodiversity is important. We need multiple species in the ecosystem to promote its functioning. We focused on plant reproduction, but it’s potentially a more general mechanism for how biological diversity may help to support services that directly benefit people.”

Surprisingly little research has been done in North America on this topic, according to entomologist Dennis vanEngelsdorp, a researcher on pollinator health and honeybee health at the University of Maryland.

“This study reemphasizes the real need for a diverse pollination force,” he said. “Some of this has been looked at in the UK and Netherlands, showing relationships between the decline of pollinators and certain plant species, but we have not done a lot of comparable studies here.”

Read more at Discovery News

Centaurs: Cross-Dressing Comets That Go As Asteroids

Who’d have thought it? Cross-dressing is no longer the preserve of humans, cameleons, magnetars and wolves in sheep’s clothing. Comets are now in on the act.

New research announced today describes the finding that many of the mysterious objects that populate orbits between Jupiter and Neptune are in fact comets. Cross-dressing comets! Live and let live is what I say.

In all honesty, astronomers have always been a little dubious about these objects’ origins, hence why these objects were named “centaurs.” Centaurs in Greek mythology are part human, part horse. Celestial centaurs therefore always had some odd characteristics that fell into the comet and asteroid category.

However, at least part of the centaur debate has been settled by NASA’s Wide-field Infrared Survey Explorer (WISE).

During the latter stages of the WISE mission, the orbiting space telescope entered the “warm” phase of its extended mission when the onboard coolant ran dry in October 2010. In an attempt to catalog previously unnoticed near-Earth objects (NEOs), WISE was used to spy out the weak infrared signal these objects emit. As part of the four-month NEOWISE mission, centaurs (and their scattered-disk object cousins) were surveyed and at least two thirds of the objects were found to be comets, not asteroids.

“Just like the mythical creatures, the centaur objects seem to have a double life,” said James Bauer of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., in a JPL news release. “Our data point to a cometary origin for most of the objects, suggesting they are coming from deeper out in the solar system.” Bauer is lead author of a paper published online July 22 in the Astrophysical Journal.

52 centaurs and scattered disk objects were surveyed, 15 of which were newly discovered by NEOWISE.

Previous observations of centaurs have uncovered comet-like behavior. For example, other observatories have imaged what appeared to be halos — cometary outgassing — around individual objects in the past. But NEOWISE was able to survey dozens of centaurs and in doing so spotted a pattern.

NEOWISE was able to gather albedo data — a measure of how shiny an object is — on the surveyed centaurs. Combined with previous albedo and color data, a picture emerged.

“Comets have a dark, soot-like coating on their icy surfaces, making them darker than most asteroids,” said the study’s co-author, Tommy Grav of the Planetary Science Institute in Tucson, Ariz. “Comet surfaces tend to be more like charcoal, while asteroids are usually shinier like the moon.”

NEOWISE found the majority of centaurs to be dark, a tell-tail sign that they are more likely comets and not asteroids.

Read more at Discovery News