Smoking and Obesity Curb Sex - LiveScience

http://www.livescience.com/humanbiology/060627_bad_habits.html

By Robert Roy Britt
LiveScience Managing Editor
posted: 27 June 2006
04:36 pm ET

For a man addicted to cigarettes and plagued by obesity, which together raise the risk of cancer and diabetes, life might seem a bit grim. At least there's sex. Well, maybe not. In a new study, scientists examined a survey database of 22,086 healthy subjects between the ages of 40 and 75, including 17.7 percent who reported new onset of erectile dysfunction between 1986 and 2000. Physical activity (beyond mere sex) played a key role in helping men avoid the dreaded ED, as clinical researchers fondly call the condition. “We found a 2.5-fold difference in risk of ED when we compared obese men who did little exercise with men who were not overweight and averaged 30 minutes of vigorous exercise a day," said Eric Rimm , associate professor of epidemiology and nutrition at the Harvard School of Public Health. Smoking, too, was associated with a higher risk of getting ED among men who previously had good erectile function. The same bad habits up the odds of getting heart disease, the researchers point out. And in fact a study earlier this year in the Archives of Internal Medicine found that ED was a warning sign for heart disease. But perhaps the idea of missing out on sex can serve as a more compelling health warning. “Many men may choose not to change to a healthier lifestyle, which includes exercise and a prudent diet, because they perceive heart disease as something that may only develop decades in the future," Rimm said. "Hopefully, these results will help to motivate men to adopt a more active lifestyle to avoid a problem which may be more immediate." The study, detailed in the July issue of the Journal of Urology, was supported by Pfizer, Inc., and by grants from the National Institutes of Health. It confirms research published in the Journal of the American Medical Association in 2004, which suggested that obese men with ED could improve their sexual function with exercise and weight loss. Equality Makes for Better Sex Study: Sexual Desire is in Your Genes SPECIAL REPORT: Toward Immortality How to Stop Smoking: Simply Don't Plan On It Obesity May Be Contagious, Scientists Say Dieting Man Slims Down to 1,000 Pounds The Odds of Dying

Huge Asteroid to Fly Past Earth July 3 - space.com

http://www.space.com/scienceastronomy/060626_asteroid_close.html

By Joe Rao SPACE.com Skywatching Columnist posted: 26 June 2006 11:50 am ET

An asteroid possibly as large as a half-mile or more in diameter is rapidly approaching the Earth. There is no need for concern, for no collision is in the offing, but the space rock will make an exceptionally close approach to our planet early on Monday, July 3, passing just beyond the Moon’s average distance from Earth.

Astronomers will attempt to get a more accurate assessment of the asteroid’s size by “pinging” it with radar.

And skywatchers with good telescopes and some experience just might be able to get a glimpse of this cosmic rock as it streaks rapidly past our planet in the wee hours Monday. The closest approach occurs late Sunday for U.S. West Coast skywatchers.

The asteroid, designated 2004 XP14, was discovered on Dec. 10, 2004 by the Lincoln Laboratory Near Earth Asteroid Research (LINEAR), a continuing camera survey to keep watch for asteroids that may pass uncomfortably close to Earth.

Although initially there were concerns that this asteroid might possibly impact Earth later this century and thus merit special monitoring, further analysis of its orbit has since ruled out any such collision, at least in the foreseeable future.

Size not known

Asteroid 2004 XP14 is a member of a class of asteroids known as Apollo, which have Earth-crossing orbits. The name comes from 1862 Apollo, the first asteroid of this group to be discovered. There are now 1,989 known Apollos.

The size of 2004 XP 14 is not precisely known. But based on its brightness, the diameter is believed to be somewhere in the range of 1,345 to 3,018-feet (410 to 920 meters). That's between a quarter mile and just over a half-mile wide.

Due to the proximity of its orbit to Earth [Map] and its estimated size, this object has been classified as a “Potentially Hazardous Asteroid” (PNA) by the Minor Planet Center in Cambridge, Massachusetts. There are currently 783 PNAs.

The latest calculations show that 2004 XP14 will pass closest to Earth at 04:25 UT on July 3 (12:25 a.m. EDT or 9:25 p.m. PDT on July 2). The asteroid’s distance from Earth at that moment will be 268,624-miles (432,308 km), or just 1.1 times the Moon’s average distance from Earth.

Spotting 2004 XP14 will be a challenge, best accomplished by seasoned observers with moderate-sized telescopes.

On April 13, 2029, observers in Asia and North Africa will have a chance to see another asteroid, but without needing a telescope. Asteroid 99942 Apophis, about 1,000 feet (300 meters) wide, is expected to be visible to the naked eye as it passes within 20,000 miles (32,000 km). Astronomers say an asteroid that large comes that close about once every 1,500 years.

Observing plans

As 2004 XP14 makes its closest approach to Earth, astronomers will attempt to gauge its size and shape by analysis of very high frequency radio waves reflected from its surface.

Such radar measurements of the exact distance and velocity of the asteroid will allow for precise information on its orbit. From this scientists can also discern details of the asteroid’s mass, as well as a measurement of its density, which is a very important indicator of its overall composition and internal structure.

Astronomers plan to utilize NASA's 70-meter (230-foot) diameter Goldstone radar, the largest and most sensitive antenna in its Deep Space Network. Located in California’s Mojave Desert, the Goldstone antenna has been used to bounce radio signals off other Near-Earth asteroids many times before, and it is now being readied to “ping” 2004 XP14 on July 3, 4 and 5.

Augmenting the Goldstone observations will be radar observations scheduled at Evpatoria in the Ukraine, commencing several hours prior to the July 3 observations at Goldstone.

Editor's Note: A SPACE.com viewer's guide for 2004 XP14 will be presented in Joe Rao's weekly Night Sky column on Friday, June 30.

• Gallery: Asteroids
• Top 10 Ways to Destroy Earth
• Video: Killer Comets and Ominous Asteroids!
• New Cosmic Defense Idea: Fight Asteroids with Asteroids
• Astronomers Gear Up for Historic Asteroid Pass in 2029
• Neptune Linked to Potential Swarm of Asteroids
• All About Asteroids

Earth's Temp at 400-Year High - LiveScience

http://www.livescience.com/environment/ap_060622_earth_hot.html

By John Heilprin
Associated Press
posted: 22 June 2006
11:37 am ET

WASHINGTON (AP)—The Earth is the hottest it has been in at least 400 years, probably even longer. The National Academy of Sciences, reaching that conclusion in a broad review of scientific work requested by Congress, reported Thursday that the "recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia.'' A panel of top climate scientists told lawmakers that the Earth is running a fever and that "human activities are responsible for much of the recent warming.'' Their 155-page report said average global surface temperatures in the Northern Hemisphere rose about 1 degree during the 20th century.

The report was requested in November by the chairman of the House Science Committee, Rep. Sherwood Boehlert, R-N.Y., to address naysayers who question whether global warming is a major threat.

Last year, when the House Energy and Commerce Committee chairman, Rep. Joe Barton, R-Texas, launched an investigation of three climate scientists, Boehlert said Barton should try to learn from scientists, not intimidate them.

The Bush administration also has maintained that the threat is not severe enough to warrant new pollution controls that the White House says would have cost 5 million Americans their jobs.

Climate scientists Michael Mann, Raymond Bradley and Malcolm Hughes had concluded the Northern Hemisphere was the warmest it has been in 2,000 years. Their research was known as the "hockey-stick'' graphic because it compared the sharp curve of the hockey blade to the recent uptick in temperatures and the stick's long shaft to centuries of previous climate stability.

The National Academy scientists concluded that the Mann-Bradley-Hughes research from the late 1990s was "likely'' to be true, said John "Mike'' Wallace, an atmospheric sciences professor at the University of Washington and a panel member. The conclusions from the '90s research "are very close to being right'' and are supported by even more recent data, Wallace said.

The panel looked at how other scientists reconstructed the Earth's temperatures going back thousands of years, before there was data from modern scientific instruments.

For all but the most recent 150 years, the academy scientists relied on "proxy'' evidence from tree rings, corals, glaciers and ice cores, cave deposits, ocean and lake sediments, boreholes and other sources. They also examined indirect records such as paintings of glaciers in the Alps.

Combining that information gave the panel "a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years,'' the academy said.

Overall, the panel agreed that the warming in the last few decades of the 20th century was unprecedented over the last 1,000 years, though relatively warm conditions persisted around the year 1000, followed by a "Little Ice Age'' from about 1500 to 1850.

The scientists said they had less confidence in the evidence of temperatures before 1600. But they considered it reliable enough to conclude there were sharp spikes in carbon dioxide and methane, the two major "greenhouse'' gases blamed for trapping heat in the atmosphere, beginning in the 20th century, after remaining fairly level for 12,000 years.

Between 1 A.D. and 1850, volcanic eruptions and solar fluctuations were the main causes of changes in greenhouse gas levels. But those temperature changes "were much less pronounced than the warming due to greenhouse gas'' levels by pollution since the mid-19th century, it said.

The National Academy of Sciences is a private organization chartered by Congress to advise the government of scientific matters.

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Pluto's Newest Moons Named Hydra and Nix - space.com

http://www.space.com/scienceastronomy/060621_nix_hydra.html


By Ker Than
Staff Writer
posted: 21 June 2006
05:06 pm ET


The International Astronomical Union has officially christened Pluto's two newest satellites Nix and Hydra.

The tiny satellites were discovered by the Hubble Space Telescope last May and are believed to have been formed from the same giant impact that carved out Charon, Pluto's third satellite, discovered in 1978.

The names were proposed this spring by the team that discovered the satellites. Before the satellites received their official names, the satellites were called P1 and P2.

In Greek mythology, Nyx was the goddess of the night and the mother of Charon, the boatsman who ferried souls across the River Styx into the underworld ruled by Pluto. The IAU changed the spelling to "Nix" after the Egyptian spelling of the goddess to avoid confusion with two asteroids that had already been named "Nyx."

The outermost of Pluto's two new satellites is named after Hydra, the nine-headed mythological serpent that guarded Pluto's realm.

"We thought it was an appropriately scary image to be the guard at the gate," said Alan Stern, an astronomer with the Southwest Research Institute who led the team that initially discovered the satellites

In addition to their relation to Pluto, the names were chosen because their first initials, "N" and "H," are also the first letters of New Horizons, the NASA spacecraft launched in January towards the Pluto system. The Hubble Space Telescope was providing support for the New Horizons mission when it spotted the tiny satellites.

"The 'P' and the 'L' in Pluto are in honor of the Percival Lowell, who instigated the search that resulted in the discovery of Pluto," Stern told SPACE.com. "The 'N' and the 'H' are exactly parallel to honor New Horizons which instigated the search that led us to [the new satellites]."

Stern said that the team also considered the name "Cerberus," the three-headed hound who also guarded the gates to Hades, but rejected it because many people associate Pluto with the Disney cartoon character, and having one object in the system named after a dog was enough.

The new names were reported yesterday on ScienceNOW.org, a publication of the American Association for the Advancement of Science. A formal announcement will be issued Friday, June 23.

Hubble Finds Pluto's Moons Less Than Colorful
Pluto Might Have Rings
Two More Moons Discovered Orbiting Pluto

Ethnocentrism - Wikipedia

http://en.wikipedia.org/wiki/Ethnocentrism
Ethnocentricity is the tendency to look at the world primarily from the perspective of one's own ethnic culture. People often feel ethnocentric while experiencing during what some call culture shock.
Various researchers study ethnocentricism as it pertains to their specialized fields. This article covers anthropology, political science and especially sociology.
This term was coined by William Graham Sumner, a social evolutionist and professor of Political and Social Science at Yale University. He defined it as the viewpoint that “one’s own group is the center of everything,” against which all other groups are judged. Ethnocentrism often entails the belief that one's own race or ethnic group is the most important and/or that some or all aspects of its culture are superior to those of other groups. Within this ideology, individuals will judge other groups in relation to their own particular ethnic group or culture, especially with concern to language, behaviour, customs, and religion. These ethnic distinctions and sub-divisions serve to define each ethnicity's unique cultural identity.
Anthropologists such as Franz Boas and Bronislaw Malinowski argued that any human science had to transcend the ethnocentrism of the scientist. Both urged anthropologists to conduct ethnographic fieldwork in order to overcome their ethnocentrism. Boas developed the principle of cultural relativism and Malinowski developed the theory of functionalism as tools for developing non-ethnocentric studies of different societies. The books The Sexual Life of Savages, by Malinowski, Patterns of Culture by Ruth Benedict and Coming of Age in Samoa by Margaret Mead (two of Boas's students) are classic examples of anti-ethnocentric anthropology.

Usage
In political science and public relations, not only have academics used the concept to explain nationalism, but activists and politicians have used labels like ethnocentric and ethnocentrism to criticize national and ethnic groups as being unbearably selfish — or at best, culturally biased (see cultural bias).
Nearly every religion, "race," or nation feels it has aspects which are uniquely valuable. (This tendency is humorously illustrated in the romantic comedy My Big Fat Greek Wedding, in which the heroine's father perpetually exalts Greek culture: "Give me any word, and I'll show you how it derives from Greek roots." "Oh, yeah, how about kimono?")
Other examples abound: Toynbee notes that Ancient Persia regarded itself the center of the world and viewed other nations as increasingly barbaric according to their degree of distance. China's very name is composed of ideographs meaning "center" and "country" respectively, and traditional Chinese world maps show China in the center. It's also important to note that it wasn't just China that bought into this idea. At the height of the Chinese empire, the Japanese, Koreans, Vietnamese, and Thai also believed China to be the centre of the universe and referred to China as the middle kingdom. To this day, Japan, Korea, and Viet Nam still refer to China as the middle kingdom. England defined the world's meridians with itself on the center line, and to this day, longitude is measured in degrees east or west of Greenwich, thus establishing as fact an Anglo-centrist's worldview. Native American tribal names often translate as some variant on "the people"; other tribes were labeled with often pejorative names. The United States has traditionally conceived of itself as having a unique role in world history—famously characterized by President Abraham Lincoln as "the last, best hope of Earth"—an outlook known as American exceptionalism.
The Japanese word for foreigner ("gaijin") can also mean "outsiders," and Japanese do not normally use the term to describe themselves when visiting other countries. It also excludes those native to the country where the speaker is. For a Japanese tourist in New York, gaijin are not Japanese tourists or New Yorkers, but those of other nationalities visiting New York.
In the United States foreigners or immigrants that are not considered residents are called "aliens" and in the case they do not hold a legal status within the country they are called "illegal aliens". The connotation of the word does not only suggest pure ethnocentrism but is in some sense a distancing language used between an American citizen and an immigrant or visitor.
[edit]

Psychological underpinnings of ethnocentrism
The psychological underpinning of ethnocentrism appears to be assigning to various cultures higher or lower status or value by the ethnocentric person who then assumes that the culture of higher status or value is intrinsically better than other cultures. The ethnocentric person, when assigning the status or value to various cultures, will automatically assign to their own culture the highest status or value.
Ethnocentrism is a natural result of the observation that most people are more comfortable with and prefer the company of people who are like themselves, sharing similar values and behaving in similar ways. It is not unusual for a person to consider that what ever they believe is the most appropriate system of belief or that how ever they behave is the most appropriate and natural behavior.
A person who is born into a particular culture and grows up absorbing the values and behaviors of the culture will develop patterns of thought reflecting the culture as normal. If the person then experiences other cultures that have different values and normal behaviors, the person finds that the thought patterns appropriate to their birth culture and the meanings their birth culture attaches to behaviors are not appropriate for the new cultures. However, since a person is accustomed to their birth culture it can be difficult for the person to see the behaviors of people from a different culture from the viewpoint of that culture rather than from their own.
The ethnocentric person will see those cultures other than their birth culture as being not only different but also wrong to some degree. The ethnocentric person will resist or refuse the new meanings and new thought patterns since they are seen as being less desirable than those of the birth culture.
The ethnocentric person may also adopt a new culture, repudiating their birth culture, considering that the adopted culture is somehow superior to the birth culture.
Tribal and familial groups are often seen to dominate in economic settings where transaction costs are high. Examples include the crime syndicates of Russia, Sicily, and the United States, prison gangs, and the diamond trade (Salter 2002).
Throughout history, warring factions have been composed of fairly homogeneous ethnic groups. Ethnic strife is seen to dominate the landscape in many parts of the world even to this day. Evolutionary psychology posits that the reason for these groupings stems from the alignment of interests among members of these groups due to their genetic similarity. Independent of evolutionary psychology, observers such as Shelby Steele have suggested that ethnocentrism is a mainstay of any modern society, and in cases such as the white and black population in the US, programs such as affirmative action serve only to relieve the moral consciences of the white population. People like Steele harbour respect for vocal racists, as they, unlike the rest of the population, are able to reveal their honest feelings regarding race and ethnicity.
[edit]

References
Salter, F.K., ed. 2002. Risky Transactions. Trust, Kinship, and Ethnicity. Oxford and New York: Berghahn.
Sow, Adama: Ethnozentrismus als Katalysator bestehender Konflikte in Afrika südlich der Sahara, am Beispiel der Unruhen in Côte d`Ivoire at: European University Center for Peace Studies (EPU).
This article or section does not cite its references or sources.You can help Wikipedia by introducing appropriate citations.
[edit]

Journals
Group Processes and Intergroup Relations, Sage Press.
[edit]

Types of ethnocentrism
American exceptionalism
Afrocentrism
Anglocentrism
Chinese nationalism
Eurocentrism
Germanocentrism
Greater Serbia
Indian nationalism, Hindu nationalism, Hindutva
Islamism, Islamic fundamentalism
Japanocentrism
Nazism, Neo-Nazism
Russocentrism, Russian Chauvinism, Eurasianism
Sinocentrism
White nationalism, White supremacy
[edit]

See also
Colonialism
Ethnic nationalism
Media and ethnicity
Cultural bias
Cultural competence
Intercultural competence
Intercultural communication principles
Cross-cultural communication
Cultural diversity
Cultural relativism
Egocentrism
Nationalism
Ethnic nepotism
Patriotism
Racism
Relativism
Supremacism
Polycentrism

New Cosmic Defense Idea: Fight Asteroids with Asteroids - space.com

http://www.space.com/scienceastronomy/060620_science_tuesday.html

By Robert Roy Britt
Senior Science Writer
posted: 20 June 2006
06:06 am ET

In a Space Age version of fighting fire with fire, French scientists have suggested using one asteroid to destroy another rather than letting Earth get pummeled.

The offbeat plan is intentionally incomplete and would allow the planet to be showered by fragments. But it might be better than a civilization-ending whack.

No asteroids are presently known to be on collision courses with Earth. But existing holes in the ground suggest that inevitably one will eventually be found. There is no firm plan for how to deflect or destroy an incoming asteroid, though scientists have pondered firing rockets at them, moving them gently with solar sails, or nudging them with nuclear explosions.

Lock and load

The new idea is to capture a relatively small asteroid—perhaps 100 feet (30 meters) wide—by sending a robot to it.

The robot would heave material from the asteroid's surface into space, and the reaction force would gradually direct the asteroid to a Lagrange point, one of a handful of nodes along Earth's orbit where the gravity of Earth and the Sun balance out. Scientists know that objects can be kept stable at a Lagrange point with little or no energy.

The captured rocky weapon would be held there, traveling around the Sun ahead of or behind the Earth, held until needed.

Then, if a large asteroid threatens to hit us, the small one is moved into its path, using the same heaving technique. The rocks collide, and the big one is broken into somewhat less harmfull bits.
The collision disperses the fragments of the incoming asteroid, so that not all of them hit the planet.

But …

Depending on the relative masses of the two objects, between 10 and 20 percent of the incoming asteroid mass would still hit, "but the fragments would be dispersed all over the Earth and, hopefully, none would be large enough to reach the ground with a large remaining destructive power," said Didier Massonnet of the CNES research center in France.

Massonnet and colleague Benoit Meyssignac say the collision should be engineered to occur at least 620,000 miles (1 million kilometers) from Earth and would take about eight months to execute from the Lagrange point.

The plan is detailed in the July-September, 2006 issue of the journal Acta Astronautica. The researchers first floated it at a scientific conference last fall.

One small asteroid that could fit the bill already been identified; it is called 2000 SG344, and Massonnet suspects there are many others that would work.

Fuel for thought

The researchers admit their entire scheme is not quite ready for prime time.

"We are more confident in our capability to capture the asteroid than in our capability to redirect it to an incoming body," Massonnet told SPACE.com. "The scenario of this last stage requires further studies on the very unstable trajectories which will be required."

Meanwhile, there is another aspect to the plan that could make it appealing.

Material mined from a small, nearby asteroid could provide liquid oxygen for other space missions more efficiently than mining it from the Moon, which other researchers have proposed. Liquid oxygen could be used as fuel at a cosmic gas station that would allow spacecraft to be launched from Earth with much smaller tanks and therefore more cheaply.

Other researchers have suggesting mining asteroids for their metals.

"Several thousands of tons of oxygen might become available sitting on the outer rim of Earth's gravity field," the researchers write.

Gallery: Earth’s Meteor Craters
Mystery of Arizona's Meteor Crater Solved
Mission Possible: Asteroid Tugboat Backed for Trial Run
Catastrophe Calculator: Estimate Asteroid Impact Effects Online
Supercomputer Takes on a Cosmic Threat
Riches in the Rubble: Mining Asteroids

Dinosaur-Era Birds Surprisingly Ducklike, Fossils Suggest - National Geographic

http://news.nationalgeographic.com/news/2006/06/060615-dinosaurs.html

Scott Norris
for National Geographic News

June 15, 2006

Fossil experts in China have unearthed a 110-million-year-old bird that is strikingly similar to today's birds, considering that it lived alongside dinosaurs.

The ducklike diver, known to science as Gansus yumenensis, shows advanced features not common in the fossil record until much more recently.

The discovery supports the view that key characteristics of modern birds evolved quickly and early, long before the demise of the dinosaurs.

It is also indirect evidence that the common ancestor of all today's birds was, like Gansus, adapted to an aquatic lifestyle.

Chinese and American paleontologists located the exquisitely preserved remains in mudstone slabs formed by sediments deposited on an ancient lake bottom.

A team led by Hai-lu You, of Beijing's Chinese Academy of Geological Sciences, made the discovery about 1,240 miles (2,000 kilometers) west of Beijing in the province of Gansu (China map).

Because the bones were buried gently and slowly in mud, many of them remain uncrushed. Soft tissues were also preserved, including flight feathers and webbing—like a duck's—between the bird's toes.

Gansus had been known previously from a single fossil foot, discovered at the same location in 1981. Fieldwork in 2003 and 2004 yielded some 50 new bird specimens, most of which appear to be Gansus.

Five of the recently discovered skeletons, virtually complete from the neck down, are described in detail in a paper by You and his colleagues, to be published in tomorrow's edition of the journal Science.

Almost a Duck

It may have looked like a duck and acted like a duck, but Gansus was no duck.

Study co-author Jerald Harris is director of paleontology at Dixie State College in St. George, Utah.

Harris says Gansus shares many skeletal features with modern birds, including the knobby knees characteristic of underwater swimmers like loons and grebes.

Moreover, he says, the preserved skin of the webbed feet shows the same microscopic structure seen in aquatic birds today.

"It was unexpected to find a bird this advanced in rocks this old," Harris said. "It tells us that the anatomical features we use to characterize modern birds evolved very quickly."

According to the researchers, Gansus is the oldest clearly established member of the subclass Ornithurae, the group most closely related to modern birds.

The Gansus fossils are only 10 to 15 million years younger than the "feathered dinosaurs" discovered a decade ago at Liaoning, in western China. (See feathered-dinosaur pictures.)

Most fossil birds dating so far back belong to a different evolutionary lineage called opposite birds. The name stems from the fact that bones in their shoulders and feet fit together opposite from the way seen in birds today.

Opposite birds made up the dominant bird group of the Cretaceous Period (145.5 to 65.5 million years ago). They disappeared along with the dinosaurs when that period ended, leaving no modern descendants.

The study authors say the fossil bed that yielded Gansus may be the earliest Cretaceous site dominated by ornithurans rather than opposite birds.

Different Interpretations

Experts differ in their assessments of how much light the Gansus fossils shed on the origins of modern-day bird groups such as ducks and other waterfowl.

The authors of the Science paper argue that, since Gansus and other ancestral species were water specialists, modern birds probably originated in an aquatic environment.

Their theory is that aquatic ornithurans like Gansus first evolved from earlier, land-based species early in the Cretaceous.

These water-based ornithurans gave rise to modern birds, which quickly spread back into nonaquatic habitats as the once dominant opposite birds declined.

But paleontologist Julia Clarke, of North Carolina State University in Raleigh, disagrees.

She says Gansus and other early fossils don't necessarily imply such a back-and-forth evolutionary shift between habitat types.

Rather, Clarke says, the findings illustrate that there was a wide range of bird types during the period that preceded the emergence of truly modern birds.

"The new findings contribute importantly to our understanding of the ecological diversity present in these close cousins of our existing birds," Clarke said. "They speak to the evolution of shape and form."

While the Gansus discoveries seem likely to fuel debate among paleontologists, experts agree that the excavation site may have even more to offer.

Luis Chiappe is a co-author of the Science paper and director of the Dinosaur Institute at the Natural History Museum of Los Angeles County, California.

Chiappe says the potential of this and other fossil localities in Gansu Province is enormous.

"I expect that 'feathered dinosaurs' and other key fossils for understanding vertebrate evolution will be unearthed from this site in the near future," Chiappe said.

Hawking Says Humans Must Colonize Space - space.com

Well, off-course, we are all concerned about global warming, nuclear wars and pendemics. Yet, it makes me smile to read that:

1. It would wipe out the human specie.

2. We still have 100 years to colonize space permenantly (before a global disaster kills all human beings on Earth).

How can anyone guess the future so accurately?

Sailom

http://www.space.com/news/060613_ap_hawking_space.html

By Sylvia Hui
Associated Press
posted: 13 June 2006
09:57 am ET

HONG KONG (AP)—The survival of the human race depends on its ability to find new homes elsewhere in the universe because there's an increasing risk that a disaster will destroy the Earth, world-renowned scientist Stephen Hawking said Tuesday.
The British astrophysicist told a news conference in Hong Kong that humans could have a permanent base on the moon in 20 years and a colony on Mars in the next 40 years.
"We won't find anywhere as nice as Earth unless we go to another star system," added Hawking, who arrived to a rock star's welcome Monday. Tickets for his lecture planned for Wednesday were sold out.
He added that if humans can avoid killing themselves in the next 100 years, they should have space settlements that can continue without support from Earth.
"It is important for the human race to spread out into space for the survival of the species," Hawking said. "Life on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global warming, nuclear war, a genetically engineered virus or other dangers we have not yet thought of."
The 64-year-old scientist—author of the global best seller "A Brief History of Time"—is wheelchair-bound and communicates with the help of a computer because he suffers from a neurological disorder called amyotrophic lateral sclerosis, or ALS.
Hawking said he's teaming up with his daughter to write a children's book about the universe, aimed at the same age range as the Harry Potter books.
"It is a story for children, which explains the wonders of the universe," his daughter, Lucy, added.
They didn't provide other details.
Top 10 List of Habitable Stars to Guide Search
Hawking Loses Bet; Changes Mind on Black Holes
The Growing Habitable Zone: Locations for Life Abound
Stephen Hawking's Doomsday Prediction Called 'Regrettable Hype'

AIDS - From Wikipedia

http://en.wikipedia.org/wiki/Aids
Acquired immunodeficiency syndrome or Acquired immune deficiency syndrome (AIDS or Aids) is a collection of symptoms and infections in humans resulting from the specific damage to the immune system caused by infection with the human immunodeficiency virus (HIV).[1] The late stage of the condition leaves individuals prone to opportunistic infections and tumors. Although treatments for AIDS and HIV exist to slow the virus's progression, there is no known cure.
HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid, and breast milk.[2][3] This transmission can come in the form of anal, vaginal or oral sex, blood transfusion, contaminated needles, exchange between mother and baby during pregnancy, childbirth, or breastfeeding, or other exposure to one of the above bodily fluids.
Most researchers believe that HIV originated in sub-Saharan Africa during the twentieth century;[4] it is now a pandemic, with an estimated 38.6 million people now living with the disease worldwide.[5] As of January 2006, the Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organization (WHO) estimate that AIDS has killed more than 25 million people since it was first recognized on December 1, 1981, making it one of the most destructive epidemics in recorded history. In 2005 alone, AIDS claimed an estimated 2.4 - 3.3 million lives, of which more than 570,000 were children.[5] A third of these deaths are occurring in sub-Saharan Africa, retarding economic growth by destroying human capital. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but routine access to antiretroviral medication is not available in all countries.[6] HIV/AIDS stigma is more severe than that associated with other life-threatening conditions and extends beyond the disease itself to providers and even volunteers involved with the care of people living with HIV.

Definition of 'Planet' Expected in September - space.com

It remains to be seen wether the new definition will satisfy every one. I hope the IAU will remember the Ockam's razor: "Everything should be made as simple as possible but not simpler".
Any complex definition - with a hidden agenda to keep textbooks as they are - is bound to failure.

Sailom

http://www.space.com/scienceastronomy/060608_planet_definition.html

By Robert Roy Britt
Senior Science Writer
posted: 08 June 2006
12:35 pm ET

Historians and educators have joined astronomers in an effort to break a deadlock on contentious discussions over a definition for the word planet.

A decision is expected in September, but history suggests rewriting the textbooks could be more challenging than finding tiny new worlds at the edge of the solar system.

The International Astronomical Union (IAU) is expected to propose wording to delineate planets from other small, round objects at its 12-day General Assembly meeting in Prague this August. The proposal will be based on recommendations from a newly formed committee that includes experts outside the realm of astronomy tasked to break a deadlock in earlier committee discussions.

Depending on the outcome of a separate controversial procedural issue—whether IAU members should be allowed to vote on such things—astronomers might then have the chance to weigh in on the definition later in the same meeting, SPACE.com has learned.

If approved, the definition would then be announced in September.

Rewrite the textbooks …

Some might think it ironic that the world's governing body for astronomy does not have a definition for planet.

The problem stretches back to the late 1990s, when astronomers began discovering Pluto-like objects in the distant reaches of our solar system.

All the newfound worlds—there are several known now—were until recently smaller than Pluto, but they are round and orbit the Sun, two characteristics that had for centuries been sufficient for the implicit definition of planet. The hitch: These small objects are typically on wild, elongated orbits that stretch well above and below the main plane of the solar system where eight of the traditional planets travel (Pluto has a wild orbit, too, which is one reason many astronomers do not consider it a planet anymore).

So what to call them? Astronomers have been arguing about it in earnest since 1999.

The controversy came to a head with the July 2005 announcement of 2003 UB313, an object roughly the size of Pluto that orbits the Sun beyond Neptune. The object's discoverer, Mike Brown of Caltech, has argued it should be called a planet.

But other astronomers say that if planethood is bestowed upon 2003 UB313, then several similar way-out bodies should gain the same status, and the number of planets in our solar system could ultimately climb into the thousands as search technology improves.

Still waiting …

The IAU had deferred judgment until it could come up with a definition.

That process was debated in an IAU committee for more than a year. But the dozen or so astronomers on the committee could not agree whether to define planet strictly by mass, or to consider orbital characteristics as well as how and where a planet formed, among other things. Last fall they argued over possibly putting adjectives in front of planet, such as gas giant, terrestrial, asteroidal and perhaps even traditional or historic to grandfather Pluto into the family of "regular" worlds. Those talks broke down, however.

Recently, the issue was handed off to a new committee that includes historians and educators, said Alan Boss, a planet-formation theorist at the Carnegie Institution of Washington who was on the first committee.

"They wanted a different perspective from that of planetary scientists," said Edward Bowell, an astronomer at Lowell Observatory who is also vice president of the IAU's Division III-Planetary Systems Sciences group.

Uncertain future

Neither Bowell nor Boss knows what exactly might happen next, however. Nor does Brian Marsden, leader of the Minor Planet Center where newfound objects are catalogued. Marsden was also on the first definition committee.

"The new committee is supposed to recommend what 'should be done' about Pluto, 2003 UB313 and other 'largish' small bodies, but it is not clear that what they decide will depend on mass," Marsden told SPACE.com.

Marsden said it's also unclear how the IAU will reach an ultimate resolution.

"The IAU made the interesting policy decision in 2003 to disenfranchise its members, and they were therefore not allowed to vote on 'scientific matters' (such as what a planet is) at the last plenary General Assembly session at the Sydney meeting [in 2003]," Marsden said. "There are rumors that there may be an administrative decision to re-enfranchise us at the first of the upcoming plenary sessions this August in Prague—so that suggested vote might be possible at the second."

That is indeed the plan, IAU General Secretary Oddbjorn Engvold explained yesterday. The advisory Committee is scheduled to meet June 30, Engvold said by email.

"Their proposal and advice will be forwarded to the IAU Executive Committee, who will present the matter for decision at the IAU General Assembly in Prague," Engvold said. "Assuming that the proposed change in voting rules will be accepted at the first session of the General Assembly, all IAU members will be allowed to vote on all scientific issues at this General Assembly."

IAU officials appear to have some confidence this will all work out. A statement on the IAU web site states: "The IAU will publish beginning of September 2006 the definition of a 'Planet.'"

Broad definition possible

Astronomers, meanwhile, are eager to know if the definition will include just mass, which would likely mean 2003 UB313 and eventually hundreds of other worlds will be added to the list of original nine planets, or if it will exclude those worlds by defining planets as being also in somewhat circular orbits or some other qualifier.

Might the definition go beyond mass, to include orbit characteristics and formation scenarios?

"Yes," IAU President Ronald Ekers told SPACE.com. "The scope of the definition may include all these aspects."

• All About Planets
• Large Planets Undefined, Too
• Gallery: Casting Our Solar System In a New Light
• Gallery: The Solar System - Sun and Nine Planets
• Video: Interplanetary Traffic Jam
• Video: Planet Hunter

Maturity of Farthest Galaxy Cluster Surprises Astronomers - space.com

Astronomers are watching a part of the universe some 10 billion light-years away. Given that the universe is thought to be 13.7 billion years old, that's a childhood picture...

This is another evidence that cosmology is a fast-changingfield This galaxy cluster appears to be very mature. What is the best explanation for galaxies to evolve so fast?

Sailom

http://www.space.com/scienceastronomy/060608_galaxy_cluster.html

By Christine L. Kulyk

Special to SPACE.com

posted: 08 June 2006

06:20 am ET

CALGARY, ALBERTA—

A ghostly blue blob amid a swarm of red dots in a new cosmic image is the superhot intergalactic gas permeating the space within the most distant cluster of galaxies found to date.
Located nearly 10 billion light-years away, Cluster XMMXCS 2215-1738 is being hailed by its discoverers as a tantalizing glimpse of what galaxy clusters were like at their earliest stages of formation.
Individual galaxies have been detected at greater distances. But the newly discovered cluster contains several hundred galaxies bound together by mutual gravitational attraction.
The finding was announced here this week at the 208th meeting of the American Astronomical Society.

Young and old

A light-year is the distance that light can travel in a year, so the light from this cluster took almost 10 billion years to reach us. Since the universe is thought to be 13.7 billion years old, the record-setting cluster must have formed when the universe was relatively young.
"Yet this distant cluster appears to be full of old galaxies," discovery team member Adam Stanford noted with amazement.
Stanford and his colleagues said the total mass of the cluster is enough to contain 500 trillion stars comparable in mass to our Sun. That's a surprising stellar mass for a galaxy cluster to have achieved at such an early era in the evolution of the universe, said Stanford, a researcher at the University of California, Davis, and at Lawrence Livermore National Laboratory.
'Hot' finding
Stanford and the other members of the XMM Cluster Survey, an international team of astronomers, made their discovery by combining X-ray observations from the European X-ray Multi Mirror (XMM) Newton satellite with optical observations using the 10-meter W.M. Keck telescope on Mauna Kea, Hawaii.
Intergalactic gas in the record-setting cluster glows with powerful x-ray emissions at a temperature of 10 million degrees, said team member Robert Nichol, from the University of Portsmouth, England. That's what made the detection of this distant cluster possible, says Nichol. It also makes this a "hot" find in every sense of the word, since this is the hottest cluster yet found at an extreme distance.
But it doesn't end there. Within the patch of the universe covered by the Cluster Survey, Nichol says they can see hints of more tan 1,600 additional galaxy clusters waiting to be confirmed and studied in detail.
"The total number of clusters depends on the amount of dark matter there is," Nichol said. "So this will give us a wonderful measure of how much dark matter there is in the universe."
Dark matter is mysterious stuff that astronomers say must exist, based on the fact that there is not enough regular matter in galaxies to keep them from flying apart.

More discoveries

Extremely distant galaxy clusters like these, Stanford said, give astronomers a great chance "to study galaxy formation by looking at what they were like in the earlier stages of their lifespan."
Stanford is also a team member for a separate galaxy-cluster study that presented its results at the same meeting. Co-led by Mark Brodwin of NASA's Jet Propulsion Laboratory in Pasadena, this team used the Spitzer Space Telescope to discover a total of almost 300 galaxy clusters and groups (galaxy "groups" contain far fewer members than the average galaxy cluster).
Nearly 100 of their finds are at immense distances of over 8 billion light-years.
"The Spitzer Space Telescope sees the thermal radiation of these galaxy clusters at infrared wavelengths," Brodwin explained. "Now, we'll be able to use this large sample of clusters as a laboratory to study the evolution of galaxies."
Nebulas: The Best of Your Amazing Images
Bevy of Black Holes Found in Galaxy Cluster
Ongoing Growth: Galaxies Grab Intergalactic Gas
VOTE NOW: Most Amazing Galactic Images Ever

Strange New Worlds Could Make Miniature Solar Systems - space.com

More troubles for the International Astronomical Union: Planet-like objects have been found floating in space without orbiting any stars! In our solar system, the traditional definition of a planet is this one: Orbiting our star (the sun) + all planets in the same solar system must orbit along the same plane (the ecliptic).
The first condition didn't make any troubles so far. However, countless "Kuiper Belt Objects" can't be called a planet because their orbit doesn't follow the ecliptic. Another reason given was that "they are too small" (smaller than Pluto). This reason didn't make much sense but it worked until the discovery of a KBO bigger than Pluto.
Now, something even worse has come to the attention of the International Astronomical Union: Something less massive than a star is not orbiting another star. Should we call it a planet anyway?
One more reason for changing the definition of a planet.
A definition based on the mass of the object would be this one:
1. Massive enough to be round-shaped.
2. Not massive enough to be a star

Another argument is this one: An asteroid is defined is an object orbiting the sun "smaller" than a planet. A star is defined as a very massive object... massive enough to involve thermonuclear fusion. Both definitions are about their mass and not about their orbit! Is it surprising that anything in between should be called a planet?
Another argument: Two stars are orbiting one another in a "binary system". Noone would argue that they are both "stars". Noone would pretend that the most massive one is the "real star" and the least massive one is actually a "planet". Why not following the same way of thinking for planets?

Sailom

http://www.space.com/scienceastronomy/060605_planemos.html


By Robert Roy Britt
Senior Science Writer
posted: 05 June 2006
11:35 am ET

Planet-like objects floating alone through space harbor disks of material that could make other planets or moons, something like miniature versions of our solar system, astronomers said today.
What exactly to call any of these objects and systems is up in the air, however.
In one new study, six objects ranging in heft from five to 15 times the mass of Jupiter were observed. None are bound to stars. All are young and have disks of gas and dust that resemble disks found around young stars. Our own Sun had such a disk, out of which asteroids, comets and planets formed, theorists say.


Planemo or brown dwarf?
The scientists involved in the new research are calling the objects "planemos," short for planetary mass objects that were born in the manner of stars and do not orbit normal stars.
"Now that we know of these planetary mass objects with their own little infant planetary systems, the definition of the word 'planet' has blurred even more," said study leader Ray Jayawardhana from the University of Toronto.
Observations at the European Southern Observatory (ESO) in Chile revealed infrared radiation from the dust disks. There are no conventional photographs of the objects. The results of this and a second, related study are being presented today at the 208th meeting of the American Astronomical Society in Calgary.
The new observations were of objects previously identified in work led by Katelyn Allers, then at the University of Texas at Austin. Allers used data from NASA's Spitzer Space Telescope.
The discoveries are not the first of their kind, however.
Last year, a group led by Kevin Luhman at Penn State found an isolated object about eight times the mass of Jupiter with an apparent disk of gas and dust. In a telephone interview today, Luhman said he prefers to use the term brown dwarf for all large, gaseous objects that are not orbiting normal stars. Brown dwarfs are generally considered to be much bigger than Jupiter but not massive enough to jumpstart thermonuclear fusion of hydrogen, the process that powers real stars and makes sunlight.
"I don't use the term planetary mass object," Luhman said. "They are really just brown dwarfs."
To understand the difference of opinion, one must first hear about the second new study, which further complicates the definitions.

Even stranger

In the other study, Subhanjoy Mohanty of the Harvard-Smithsonian Center for Astrophysics and colleagues looked at another so-called planemo and found evidence for a dust disk.
The object, named 2M1207b, was discovered in 2004 and controversially hailed then as providing the first picture of an extrasolar planet.
While clearly of planetary weight, at about eight times as massive as Jupiter, 2M1207b orbits a brown dwarf. Researchers suspect both objects formed at once by condensing out of an interstellar cloud of material—exactly how binary star systems are thought to form and unlike the typical process of planet birth.
The brown dwarf is about 25 times the mass of Jupiter but still only about 8 percent as massive as our Sun. Like all brown dwarfs, it burns deuterium (which means it is at least 13 to 15 times the mass of Jupiter) but lacks enough heft to force thermonuclear fusion.
Jayawardhana, who worked on this study too, said: "It is quite likely that smaller planets or asteroids could now form in the disk around each one."

Avoiding the debate

By using the term planemo, the researchers are purposely avoiding the debate over whether 2M1207b and the free-floating objects should be called planets.
"Whether you call it a planet or not depends on your definition of the word 'planet,' whether it's a definition based on mass or one based on formation scenario," Jayawardhana told SPACE.com. "In any case, we have chosen to call it a planetary mass companion, rather than getting into a debate about how to define a planet."
Such a definition is the responsibility of the International Astronomical Union (IAU), which in recent years has been working—so far unsuccessfully—to draft language that defines planets both big and small.
If a planemo is a planetary mass object, however, then why are Jayawardhana and his colleagues describing the setups they've found as miniature solar systems rather than miniature Jovian systems?
"You can perhaps describe it as a big Jovian system too," he said. "The reason we describe [them] as mini-solar systems is because the central objects probably formed more like stars than like planets."
Luhman, the Penn State astronomer, doubts the IAU will adopt the term planemo. He said it is so difficult to pin down the masses of these things that distinguishing between a planetary mass object and a certain brown dwarf is very challenging. It makes more sense, he said, to call them all brown dwarfs if they formed in isolation and are not true stars.
Whatever the terminology, the findings suggest a whole new world of cosmic possibilities.
"The diversity of worlds out there is truly remarkable," Jayawardhana said. "Nature often seems more prolific than our imagination."
Amazing Cosmic Image Galleries
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Does a giant crater lie beneath the Antarctic ice? - Nature

A dense bit of rock in the Antarctic (orange circle) seems to be circled by a crater.

© Ohio State University


http://www.nature.com/news/2006/060529/full/060529-11.html

Published online: 2 June 2006; | doi:10.1038/news060529-11

Signs of an ancient impact could help to explain a mass extinction.

Mark Peplow

Evidence of a cataclysmic meteorite impact has been unearthed in Antarctica, according to researchers who say the collision could possibly explain the greatest mass extinction ever seen on our planet. But scientists contacted by news@nature.com say they are sceptical, as no signs of such an enormous impact have been found in other, well-studied areas of Antarctica.

The first sign of this possible impact was spotted by NASA's GRACE satellites, a pair of orbiting probes that sense slight variations in the Earth's gravity field. They revealed a 320-kilometre-wide plug of dense mantle material more than 1.6 kilometres beneath the East Antarctic ice sheet in an area known as Wilkes Land.

This mass concentration, or 'mascon', can be caused by the upwelling of denser material from the Earth's mantle after a massive impact. "If I saw this mascon signal on the Moon, I'd expect to see a crater around it," says Ralph von Frese, a geophysicist at Ohio State University, Columbus, who led the team that made the find.

When they looked at airborne radar images of the area, they found what they say looks like a crater — a circular ridge some 500 kilometres wide running around the mascon. "It could be the biggest impact ever found on Earth," says von Frese.

Incoming!

"It's possible, but it's not the interpretation that would top your list," says Ian Dalziel, a geologist at the University of Texas at Austin. The region of dense rock is certainly circular, he says, but it could easily be volcanic rock that had welled up during normal geological activity: "You can find a lot of gravity anomalies like this." The roughly circular feature thought to be the rim of the crater may just be part of the normal variation in terrain in the area, he adds.

If an incoming asteroid did gouge out the hole it must have been up to 50 kilometres across, says von Frese. That's four or five times larger than the object thought to have created the Chicxulub crater on the Yucatan peninsula in Mexico, which was probably responsible for wiping out the dinosaurs some 65 million years ago.

But that's peanuts compared with the Permian-Triassic extinction, which destroyed more than three-quarters of all species on Earth about 250 million years ago. The cause of this mass extinction is still hotly debated by scientists.

Most think that the extinction started when a vast volcanic eruption released a flood of lava to create the Siberian Traps — an area of basalt that covers an area larger than Europe. "They represent the biggest volcanic event of all time, and coincide precisely with the extinction," says Paul Wignall, a palaeontologist at the University of Leeds, UK, who studies mass-extinction events. Such an eruption would have belched huge amounts of gas, including sulphur dioxide and carbon dioxide, into the atmosphere, causing acid rain and greenhouse warming.

Other scientists have argued that a massive impact, like that at Chicxulub, could be responsible instead (see 'Comet impact theory faces repeat analysis'). "But nobody's been convinced of that," says Wignall.

Von Frese notes that the explanations aren't mutually exclusive: the shockwaves from a huge impact could have travelled through the planet to trigger the eruptions in Siberia, delivering a devastating combination of disasters.

Hot topic

Von Frese presented the discovery at an American Geophysical Union meeting in Baltimore, Maryland in late May. He admits that it was greeted with "a lot of scepticism", largely because there's no direct evidence that the feature is 250 million years old.

An impact of that size should also have melted and twisted nearby rock. Yet rocks in the Transantarctic Mountains of the same age show no evidence of the collision, says Jane Francis, a geologist also at the University of Leeds. "That sequence has been worked on before, and no one has found evidence to support a massive impact like this," she says.

Wignall says that few scientists will be convinced by the hypothesis until the team can precisely date their crater directly, and find rocks there that have been altered by the searing heat of the explosion. "Then we'll all sit up and take notice," he says.

Too much ice covers the putative crater for a drilling expedition. But Von Frese hopes to make a research trip to Antarctica to look for rocks at the base of the ice sheet along the continent's coast that could attest to an impact.

Visit our newsblog to read and post comments about this story.

Polar core is hot stuff - Nature

An underwater mountain range near the North Pole tells a story of arctic climates past.
© Martin Jakobsson/IBCAO


http://www.nature.com/news/2006/060529/full/060529-5.html


There was once little difference between equatorial and arctic climates.

Quirin Schiermeier

A core of sediment pulled from the bottom of the Arctic Ocean has confirmed that, millions of years ago, the North Pole was as warm as a balmy summer day.

Drilling in the Arctic Ocean poses enormous technical difficulties, so relatively little has been discovered about the region's climate history. Now, the spoils of the Arctic Coring Expedition (ACEX), extend our knowledge from about half a million years to 80 million years ago.

"This will boost understanding of climate evolution, in the Arctic and globally," says Ursula Röhl, a marine geologist at the University of Bremen in Germany. "It's really fantastic that such an enormous advance is still possible these days.

"Some initial findings from the cruise were released two years ago (see 'North Pole once enjoyed Mediterranean climate'). Now the researchers report several analyses of the sediment core in Nature1.

The results are unexpected. Not only did the Arctic heat up to an extent that is inexplicable by current climate models, say the researchers, it also seems that the North Pole began to cool at about the same time as the Antarctic. This timing suggests that climate was being driven by a global factor, such as atmospheric levels of greenhouse gases, rather than something more local, such as geological upheaval.

"This is a major, major surprise," says Jan Backman, a marine geologist at Stockholm University in Sweden, who co-led the expedition.

Party of ice-breakers

Part of the Integrated Ocean Drilling Program, the US$10-million ACEX project was an adventurous undertaking.

In August 2004, two ice-breakers cleared the Vidar Viking's path to the Lomonosov ridge, a chain of underwater mountains that lie more than 975 metres below the ocean surface and rise up to 3 kilometres above the sea floor. These ice-breakers then sheltered the ship while it drilled for a record-breaking 430 metres of sediment at a point 250 kilometres from the North Pole. Previous cores were only 10 metres long at most.

The isotopic composition of organic carbon from shells and algae in the sediment reveals information about past temperatures. During a period of pronounced warming 55 million years ago, known as the Palaeocene/Eocene thermal maximum, average summertime temperatures in the Arctic Ocean rose to almost 24°C. This is ten degrees higher than what climate models for the period have come up with.

"The Eocene climate apparently knew surprisingly little differences between the poles and the equator," says Röhl.

Scientists believe that the atmosphere at the time was exceptionally rich in greenhouse gases. But Appy Sluijs, a palaeoclimatologist at Utrecht University in the Netherlands and first author of one of the papers2, says that Arctic warming must have been amplified by an additional factor — possibly heat-trapping stratospheric clouds or hurricane-induced ocean mixing.

Impeccable timing

The sediment core also reveals the timing of the north's heating and subsequent cooling. Scientists have found evidence of the Antarctic starting to ice up from 43 million years ago. But evidence of glaciation and sea ice at the North Pole had only been found from about 6 million to 10 million years ago4.

Now geologists have found sand and pebbles in the central Arctic basin that they think can only have been carried there by icebergs 45 million years ago. So it seems that Arctic glaciation began around the same time as the southern freeze. "It revolutionizes our view on how ice and climate developed," says Backman.

"Understanding the geological past is absolutely essential for modellers," adds Röhl. "Only climate simulations that are able to correctly reproduce the past are likely to accurately predict the future."

Visit our newsblog to read and post comments about this story.


References
Moran K., et al. Nature, 441. 601 - 605 (2006). Article
Brinkhuis H., et al. Nature, 441. 606 - 609 (2006). Article
Sluijs A., et al. Nature, 441. 610 - 613 (2006). Article
Lear C. H., Elderfield P. H. & Wilson P. A. Science, 287. 269 - 272 (2000). Article PubMed ISI ChemPort