New Evidence of Dinosaurs' Role in the Evolution of Flight

A new study looking at the structure of feathers in bird-like dinosaurs has shed light on one of nature's most remarkable inventions – how flight might have evolved. Academics at the Universities of Bristol, Yale and Calgary have shown that prehistoric birds had a much more primitive version of the wings we see today, with rigid layers of feathers acting as simple airfoils for gliding. Close examination of the earliest theropod dinosaurs suggests that feathers were initially developed for insulation, arranged in multiple layers to preserve heat, before their shape evolved for display and camouflage. As evolution changed the configuration of the feathers, their important role in the aerodynamics and mechanics of flight became more apparent. Natural selection over millions of years ultimately modified dinosaurs' forelimbs into highly-efficient, feathered wings that could rapidly change its span, shape and area – a key innovation that allowed dinosaurs to rule the skies. This basic wing configuration has remained more or less the same for the past 130 million years, with bird wings having a layer of long, asymmetrical flight feathers with short covert feathers on top. They are able to separate and rotate these flight feathers to gain height, change direction and even hover. This formation allows birds to move in such a way as to produce both lift and thrust simultaneously – a capability that man, with the help of technology, is still trying to successfully imitate. The research, published in Current Biology, looked at the dinosaur Anchiornis huxleyi and the Jurassic bird Archaeopteryx lithographica. The latter is 155 million years old and widely considered to be the earliest known bird, presenting a combination of dinosaur and bird characteristics. Their wings differed from modern day birds in being composed of multiple layers of long feathers, appearing to represent early experiments in the evolution of the wing. Although individual feathers were relatively weak due to slender feather shafts, the layering of these wing feathers is likely to have produced a strong airfoil. The inability to separate feathers suggests that taking off and flying at low speeds may have been limited, meaning that wings were primarily used in high-speed gliding or flapping flight. Jakob Vinther, from the Univ. of Bristol's Schools of Biological and Earth Sciences, says: "We are starting to get an intricate picture of how feathers and birds evolved from within the dinosaurs. We now seem to see that feathers evolved initially for insulation. Later in evolution, more complex vaned or pinnate feathers evolved for display. "These display feathers turned out to be excellent membranes that could have been utilised for aerial locomotion, which only very late in bird evolution became what we consider flapping flight. This new research is shedding light not just on how birds came to fly, but more specifically on how feathers came to be the way they are today - one of the most amazing and highly specialised structures in nature." Nicholas Longrich of Yale Univ. added: "By studying fossils carefully, we are now able to start piecing together how the wing evolved. Before, it seemed that we had more or less modern wings from the Jurassic onwards. Now it's clear that early birds were more primitive and represented transitional forms linking birds to dinosaurs. We can see the wing slowly becoming more advanced as we move from Anchiornis, to Archaeopteryx, to later birds."

Oxygen envelops Saturn's icy moon

A Nasa spacecraft has detected oxygen around one of Saturn's icy moons, Dione.

The discovery supports a theory that suggests all of the moons near Saturn and Jupiter might have oxygen around them.

Researchers say that their finding increases the likelihood of finding the ingredients for life on one of the moons orbiting gas giants.

The study has been published in Geophysical Research Letters.

According to co-author Andrew Coates of University College London, Dione has no liquid water and so does not have the conditions to support life. But it is possible that other moons of Jupiter and Saturn do.

"Some of the other moons have liquid oceans and so it is worth looking more closely at them for signs of life," Prof Coates said.

The discovery was made using the Cassini spacecraft, which flew by Dione nearly two years ago. Instruments on board the unmanned probe detected a thin layer of oxygen around the moon, so thin that scientists prefer to call it an "exosphere" rather than an atmosphere.

But the discovery is important because it suggests there is a process at work around the solar system's gas giants, Saturn and Jupiter, in which oxygen is released from their icy satellites.

It seems that highly charged particles from the planets' powerful radiation belts split the water in the ice into hydrogen and oxygen.

Dione's sister moon, Enceladus is thought to harbour a liquid ocean below its icy surface. The same is thought to be true of Europa, Callisto and Ganymede which orbit Jupiter.

Prof Coates is among a group of scientists lobbying the European Space Agency to send an orbiter to explore Jupiter's icy moons - known as the Juice mission.

"These are fascinating places to look for signs of life," he said.

As is Titan, Saturn's largest satellite. Its nitrogen and methane atmosphere is reminiscent of the early Earth, according to Prof Coates.

"It may be an Earth waiting to happen as the outer Solar System warms up," he said.

Nasa is developing a proposal to send a landing craft, or lander, to float on one of the planet's oily lakes.

Dinosaurs had fleas too _ giant ones, fossils show

Handout photo released by the Nature magazine and obtained on Feburary 28, 2012 shows a female flea from the early Cretaceous period. The giant dinosaurs that roamed the world some 150 million years ago shared the planet with equally daunting parasites: blood-gobbling fleas that were up two centimetres (almost an inch) long. –AFP PHOTO / Nature / D. Huang
WASHINGTON: In the Jurassic era, even the flea was a beast, compared to its minuscule modern descendants. These pesky bloodsuckers were nearly an inch (25 millimeters) long.

New fossils found in China are evidence of the oldest fleas _ from 125 million to 165 million years ago, said Diying Huang of the Nanjing Institute of Geology and Paleontology. Their disproportionately long proboscis, or straw-like mouth, had sharp weapon-like serrated edges that helped them bite and feed from their super-sized hosts, he and other researchers reported Wednesday in the journal Nature.

Scientists figure about eight or more of today’s fleas would fit on the burly back of their ancient ancestor.

‘‘That’s a beast,’’ said study co-author Michael Engel, entomology curator at the Natural History Museum at the University of Kansas. ‘‘It was a big critter. I can’t even imagine coming home and finding my miniature schnauzer with one or more of these things crawling around on it.’’

The ancient female fleas were close to twice the size of the males, researchers found, which fits with modern fleas.

Engel said it is not just the size, however, that was impressive about the nine flea fossils. It was their fearsome beak capable of sticking into and sucking blood from the hides of certain dinosaurs, probably those that had feathers.

These flea beaks ‘‘had almost like a saw running down the side,’’ Engel said. ‘‘This thing was packing a weapon. They were equipped to dig into something.’’

While the ancient fleas were big, they had one disadvantage compared to modern ones: Their legs were not well developed. Evolving over time, fleas went from crawling to jumping, Huang said.

‘‘Luckily for the land animals of the Mesozoic, these big flat fleas lacked the tremendous jumping capacity that our common fleas have,’’ said Joe Hannibal of the Cleveland Museum of Natural History. He was not involved in the study, but he praised it as useful and interesting.

Just finding the fleas was a stroke of luck, Huang said. He first found one in a Chinese fossil market and mentioned it to someone at his hotel. The other guest showed him a photo of another fossilized flea, telling him it was from Daohugou in northeastern China, where there is a famous fossil bed from about 165 million years ago. Huang went there and found fleas preserved in a brownish film of volcanic ash. The grains of rock were so fine you could see antennae and other details of the fleas, he said.

Modern fleas get engorged after they feast on blood, but these did not seem engorged, Engel said.

It should not seem very surprising that large fleas existed more than 100 million years ago. If you go back even farther in time, ancestors of dragonflies and damsel flies had 3-foot-long (1 meter-long) wingspans, Engel said.

Dinosaurs may have been wiped out by a massive 25 mile wide meteor - four times bigger than the asteroid previously though to be behind their extinction।

The deepest part of the Shiva basin, in red in this elevation diagram, is three miles below the surface of the Indian Ocean Photo: KYLE MCQUILKIN

Researchers believe they have discovered the world's biggest crater off the coast of India which they think may be responsible for the extinction of dinosaurs 65 million years ago.

The mysterious Shiva basin, named after the Hindu God, has a diameter of 310.7 miles along the seafloor and has a central peak of some 3 miles, as tall as Mount McKinley, the highest mountain in North America.

This dwarfs the meteor that was thought to have killed off the dinosaurs which measured between five and six miles and lies in the Yucatan Peninsula in Mexico.

That impact left a crater with a diameter of 180 kilometres.

Sankar Chatterjee of Texas Tech University, who led the research, said: "If we are right, this is the largest crater known on our planet.

"Rocks from the bottom of the crater will tell us the telltale sign of the impact event from shattered and melted target rocks. And we want to see if there are breccias, shocked quartz, and an iridium anomaly."

Asteroids are rich in iridium, and such anomalies are thought of as the fingerprints of an impact.

Mr Chatterjee believes the impact of an asteroid or comet of this size would have vaporized the Earth's crust on collision, killing most life and leaving ultra-hot mantle material to well up in its place.

The force of the impact broke the Seychelles islands off of the Indian tectonic plate and sent them drifting towards Africa. Much of the 30-mile-thick granite layer in the western coast of India was also destroyed.

Most of the crater lies submerged on India's continental shelf, but some tall cliffs rise above the sea, bringing active faults and hot springs. The area is a rich source of oil and gas reserves.

The team plans to visit India again to drill into the centre of the crater for clues to prove the basin was formed by a gigantic impact.

Mr Chaterjee will present his research this month at the Annual Meeting of the Geological Society of America.

A particle God doesn’t want us to discover

Could the Large Hadron Collider be sabotaging itself from the future, as some physicists say

Jonathan Leake

Explosions, scientists arrested for alleged terrorism, mysterious breakdowns — recently Cern’s Large Hadron Collider (LHC) has begun to look like the world’s most ill-fated experiment.

Is it really nothing more than bad luck or is there something weirder at work? Such speculation generally belongs to the lunatic fringe, but serious scientists have begun to suggest that the frequency of Cern’s accidents and problems is far more than a coincidence.

The LHC, they suggest, may be sabotaging itself from the future — twisting time to generate a series of scientific setbacks that will prevent the machine fulfilling its destiny.

At first sight, this theory fits comfortably into the crackpot tradition linking the start-up of the LHC with terrible disasters. The best known is that the £3 billion particle accelerator might trigger a black hole capable of swallowing the Earth when it gets going. Scientists enjoy laughing at this one.

This time, however, their ridicule has been rather muted — because the time travel idea has come from two distinguished physicists who have backed it with rigorous mathematics.

What Holger Bech Nielsen, of the Niels Bohr Institute in Copenhagen, and Masao Ninomiya of the Yukawa Institute for Theoretical Physics in Kyoto, are suggesting is that the Higgs boson, the particle that physicists hope to produce with the collider, might be “abhorrent to nature”.

What does that mean? According to Nielsen, it means that the creation of the boson at some point in the future would then ripple backwards through time to put a stop to whatever it was that had created it in the first place.

This, says Nielsen, could explain why the LHC has been hit by mishaps ranging from an explosion during construction to a second big bang that followed its start-up. Whether the recent arrest of a leading physicist for alleged links with Al-Qaeda also counts is uncertain.

Nielsen’s idea has been likened to that of a man travelling back through time and killing his own grandfather. “Our theory suggests that any machine trying to make the Higgs shall have bad luck,” he said.

“It is based on mathematics, but you could explain it by saying that God rather hates Higgs particles and attempts to avoid them.”

His warnings come at a sensitive time for Cern, which is about to make its second attempt to fire up the LHC. The idea is to accelerate protons to almost the speed of light around the machine’s 17-mile underground circular racetrack and then smash them together.

In theory the machine will create tiny replicas of the primordial “big bang” fireball thought to have marked the creation of the universe. But if Nielsen and Ninomiya are right, this latest build-up will inevitably get nowhere, as will those that come after — until eventually Cern abandons the idea altogether.

This is, of course, far from being the first science scare linked to the LHC. Over the years it has been the target of protests, wild speculation and court injunctions.

Fiction writers have naturally seized on the subject. In Angels and Demons, Dan Brown sets out a diabolical plot in which the Vatican City is threatened with annihilation from a bomb based on antimatter stolen from Cern.

Blasphemy, a novel from Douglas Preston, the bestselling science-fiction author, draws on similar themes, with a story about a mad physicist who wants to use a particle accelerator to communicate with God. The physicist may be American and the machine located in America, rather than Switzerland, but the links are clear.

Even Five, the TV channel, has got in on the act by screening FlashForward, an American series based on Robert Sawyer’s novel of the same name in which the start-up of the LHC causes the Earth’s population to black out for two minutes when they experience visions of their personal futures 21 years hence. This gives them a chance to change that future.

Scientists normally hate to see their ideas perverted and twisted by the ignorant, but in recent years many physicists have learnt to welcome the way the LHC has become a part of popular culture. Cern even encourages film-makers to use the machine as a backdrop for their productions, often without charging them.

Nielsen presents them with a dilemma. Should they treat his suggestions as fact or fiction? Most would like to dismiss him, but his status means they have to offer some kind of science-based rebuttal.

James Gillies, a trained physicist who heads Cern’s communications department, said Nielsen’s idea was an interesting theory “but we know it doesn’t happen in reality”.

He explained that if Nielsen’s predictions were correct then whatever was stopping the LHC would also be stopping high-energy rays hitting the atmosphere. Since scientists can directly detect many such rays, “Nielsen must be wrong”, said Gillies.

He and others also believe that although such ideas have an element of fun, they risk distracting attention from the far more amazing ideas that the LHC will tackle once it gets going.

The Higgs boson, for example, is thought to give all other matter its mass, without which gravity could not work. If the LHC found the Higgs, it would open the door to solving all kinds of other mysteries about the origins and nature of matter. Another line of research aims to detect dark matter, which is thought to comprise about a quarter of the universe’s mass, but made out of a kind of particle that has so far proven impossible to detect.

However, perhaps the weirdest of all Cern’s aspirations for the LHC is to investigate extra dimensions of space. This idea, known as string theory, suggests there are many more dimensions to space than the four we can perceive.

At present these other dimensions are hidden, but smashing protons together in the LHC could produce gravitational anomalies, effectively tiny black holes, that would reveal their existence.

Some physicists suggest that when billions of pounds have been spent on the kit to probe such ideas, there is little need to invent new ones about time travel and self-sabotage.

History shows, however, it is unwise to dismiss too quickly ideas that are initially seen as science fiction. Peter Smith, a science historian and author of Doomsday Men, which looks at the links between science and popular culture, points out that what started as science fiction has often become the inspiration for big discoveries.

“Even the original idea of the ‘atomic bomb’ actually came not from scientists but from H G Wells in his 1914 novel The World Set Free,” he said.

“A scientist named Leo Szilard read it in 1932 and it gave him the inspiration to work out how to start the nuclear chain reaction needed to build a bomb. So the atom bomb has some of its origins in literature, as well as research.”

Some of Cern’s leading researchers also take Nielsen at least a little seriously. Brian Cox, professor of particle physics at Manchester University, said: “His ideas are theoretically valid. What he is doing is playing around at the edge of our knowledge, which is a good thing.

“He is pointing out that we don’t yet have a quantum theory of gravity, so we haven’t yet proved rigorously that sending information into the past isn’t possible.

“However, if time travellers do break into the LHC control room and pull the plug out of the wall, then I’ll refer you to my article supporting Nielsen’s theory that I wrote in 2025.”

This weekend, as the interest in his theories continued to grow, Nielsen was sounding more cautious. “We are seriously proposing the idea, but it is an ambitious theory, that’s all,” he said. “We already know it is not very likely to be true. If the LHC actually succeeds in discovering the Higgs boson, I guess we will have to think again.”

End of the Big Beasts

by Peter Tyson

Who or what killed off North America's mammoths
and other megafauna 13,000 years ago?

It takes a certain kind of person to tackle this question in earnest. You have to be itching to know the answer yet patient as a Buddha, for the answer is frustratingly elusive. I know I'm not the type. I'm intrigued by the question but far too anxious to calmly accept, as some experts suggest, that it might be years or decades, if ever, that a definitive, widely accepted solution will come. (To follow the long-running wrangle over this question, see The Extinction Debate.)

The four people I spoke to about the megafaunal or "large-animal" extinctions possess this sort of edgy sangfroid. While keeping an open mind, they also stand in four decidedly different camps regarding why America's rich complement of big beasts went extinct quite suddenly at the end of the Ice Age. The four camps are known tongue-in-cheek as "overkill," "overchill," "overill," and "overgrill"*:

• Archeologist Gary Haynes, University of Nevada Reno, and others think that the continent's first human hunters, fresh from Siberia, killed the megafauna off as they colonized the newly discovered land.

• Donald Grayson, an archeologist at the University of Washington, Seattle, along with colleague David Meltzer of Southern Methodist University, believes that climate changes at the end of the Pleistocene epoch triggered the collapse.

• Mammalogist Ross MacPhee of the American Museum of Natural History has advanced the idea, with virologist Preston Marx, that a virulent "hyperdisease" brought by the first Americans might have raced through species with no natural immunity, bringing about their demise.

• And, in the newest hypothesis advanced, geologist James Kennett, U.C. Santa Barbara, and colleagues propose that a comet impact or airburst over North America did it.

So why is the answer so elusive? As often happens in the paleosciences, it largely comes down to lack of empirical evidence, something all four hypotheses arguably suffer from. (There's a fifth hypothesis, actually—that a combination of overkill and overchill did it.)

Overkill

In the early 1960s, ecologist Paul Martin of the University of Arizona postulated that the first Americans, after crossing into the Americas over the Bering Land Bridge, hunted the megafauna to extinction. For many years, "overkill" became the leading contender. The timing seemed more than coincidental: Humans were thought to have arrived no earlier than about 14,000 years ago, and by roughly 13,000 years ago, most of the megafaunal species abruptly vanish from the fossil record. (See a list of all 35 extinct genera of North American Ice Age mammals.)

But skeptics have asked, Where's the evidence? Grayson and Meltzer (overchill) have noted that late-Ice Age sites bearing megafaunal remains that show unequivocal sign of slaughter by humans number just 14. Moreover, they stress, only two types of giants were killed at those 14 sites, mammoth and mastodon. There's no sign that early hunters preyed on giant ground sloths, short-faced bears, or the massive, armadillo-like glyptodonts, for instance. (Forensic studies of a cache of Clovis tools found in 2008 suggest the Clovis people did hunt now-extinct camels and horses.) That's hardly enough evidence, Grayson and Meltzer argue, to lay blame for a continent's worth of lost megafauna at the foot of the first Americans.

Gary Haynes (overkill) begs to differ. "I don't care what anybody else says, 14 kill sites of mammoth and mastodon in a very short time period is extraordinary," he told me. It's one thing to find a campsite with some animal bones in it, he says, quite another to find the actual spot where an ancient hunter felled and butchered an animal—where, say, a spearpoint turns up still sticking in bone. "It's very, very rare to find a kill site anywhere in the world," he says. And absence of other megafauna in kill sites doesn't mean they weren't hunted. "There is no doubt Native Americans were eating deer and bear and elk," Haynes says, citing several large mammals that pulled through. "But you cannot find a single kill site of them across 10,000 years."

The dearth of widely convincing evidence only serves as a spur.

Could what scholars agree must have been a relatively modest initial population of hunters have emptied an entire continent of its megafauna virtually overnight, geologically speaking? (In fact, it's three continents: South America and, to a lesser extent, Northern Eurasia also lost many large species at the end of the Ice Age.) For his part, Ross MacPhee (overill) finds it hard to swallow. "I just don't think it's plausible, especially if we're also talking about collapses for megafauna that didn't actually go extinct." Certain populations of surviving big beasts, including bison in North America and musk oxen in Asia, are known to have fallen precipitously at the end of the Ice Age. "It gets a little bit beyond probability in my view that people could have been so active as to hunt every animal of any body size, in every context, in every possible environment, over three continents."

Overchill

Could climate change have done it? Scholars generally agree that North America witnessed some rapid climate adjustments as it shook off the Ice Age beginning about 17,000 years ago. The most significant swing was a cold snap between about 12,900 and 11,500 years ago. Known as the Younger Dryas, this partial return to ice-age conditions may have stressed the megafauna and their habitats sufficiently to cause widespread die-offs, Grayson and others believe.

Detractors, again, point to the lack of evidence. "There aren't any deposits of starved or frozen or somehow naturally killed animals that are clearly non-cultural in origin that you would expect if there was an unusual climate swing," says Haynes. "I don't think that evidence exists." Another question dissenters have is how the megafauna survived many abrupt glacial and deglacial shifts during the past two million years only to succumb to the one that closed the Pleistocene. "It just doesn't hold water," Jim Kennett (overgrill) told me.

Grayson admits that overchill advocates have failed to develop the kind of records needed to test climate hypotheses in detail. But he focuses on climate change, he says, because he sees absolutely no sign that people were involved. "You can't look at climate and say climate didn't do it for the simple reason that we don't really know what to look for," Grayson told me. "But what you can do fairly easily is look at the evidence that exists for the overkill position. That position would seem to make fairly straightforward predictions about what the past should have been like, and when you look to see if it was that way, you don't find it."

Overill

A lack of data has particularly plagued the "overill" hypothesis. This is the notion that diseases brought unwittingly by newly arriving people, either in their own bodies or in those of their dogs or perhaps rats, could have killed off native species that had no natural immunity. MacPhee devised this hypothesis with Preston Marx after realizing that the link between initial human arrival and subsequent large-animal extinctions was strong not just in North America but in many other parts of the world (see map in sidebar), but that in his opinion, convincing evidence for hunting as the culprit simply did not exist.

Despite what he calls "prodigious effort" using DNA techniques and immunological probes, however, MacPhee and his colleagues have failed to detect clues to any pathogens in megafaunal bones, much less nail down a specific disease, like rabies or rinderpest, that could have jumped from one type of animal to another and wiped out all the big beasts. "There's no evidence, and there's virtually no possibility of getting any evidence," Kennett told me.

"[Overill] doesn't even have circumstantial evidence, because we can't prove there was hyperdisease," Haynes says. "We can prove people were here, and we can prove climates were changing." Fair enough, says MacPhee, though he points out that the burgeoning ability of Asian bird flu to infect across species boundaries seems to suggest that some diseases are ecologically and genetically preordained to, as he puts it, "go hyper."

Overgrill

The most recent hypothesis, advanced by Kennett and 25 other scientists in a 2007 Proceedings of the National Academy of Sciences paper, concerns the proposed cosmic impact. Right about the time the Younger Dryas began and at least 15 of those 35 extinct mammals and arguably the Clovis culture itself appear to vanish abruptly from the fossil record—that is, right about 12,900 years ago—Kennett et al see markers of a major catastrophe. The markers lie in a thin layer at the base of a "black mat" of soil that archeologists have identified at over 50 Clovis sites across North America.

According to Kennett, fieldworkers have uncovered fossils of the 15 genera of mammals that survived right up to Younger Dryas times just beneath—but neither within nor above—this black mat. (Some fossil bones butt up against this layer so closely that the mat has blackened them, Kennett told me.) Stone-tool remains of the Clovis culture also end just beneath the mat, he says. Moreover, Kennett and the team he works with have identified charcoal, soot, microscopic diamonds, and other trace materials at the base of the mat. These materials indicate, he says, that a comet (not an asteroid—different constituents) exploded in the atmosphere or struck the surface, likely in pieces. This triggered widespread wildfires and extinctions, changed ocean circulation, and coughed up sun-blocking ash and dust, all of which helped unleash the Younger Dryas. Tokens of this cosmic cataclysm have shown up in the Greenland ice sheet as well, Kennett says.

Aren't you just dying to know what happened?

Where then, skeptics ask, is the crater? Unlike the asteroid strike at the end of the Cretaceous, the one thought to have ended the reign of the dinosaurs, this 12,900-year-old event currently has no hole or holes definitively linked to it. Kennett says it's still early, noting that it took nearly a decade for scientists to discover the dinosaur-ending impact crater after evidence for a cosmic collision 65 million years ago first turned up in sedimentary layers around the world. Then again, there may be no crater, Kennett says. He cites Tunguska: In 1908, an object that scholars believe was a meteor or comet exploded high above the Tunguska River in Siberia, leveling trees over 800 square miles but leaving no crater.

Critics also take issue with the black-mat evidence. Haynes (overkill) argues that the mat's charcoal-rich layer could as likely be from human-caused fires as from comet-caused wildfires, while Grayson (overchill) questions the purported collapse of Clovis populations, for which he and many other archeologists see very little evidence.

Finally, there are the extinctions themselves. Of the 35 extinct genera, 20 or so cannot be shown to have survived up to the Younger Dryas. The youngest date, for example, for fossils of Eremotherium, a giant ground sloth, is 28,000 years ago. "So the idea that this impact could have caused the extinctions of all these animals just does not make sense," Grayson says. In response, Kennett points out that the fossil record is imperfect, and one would not expect to see the most recent occurrence of rare forms like Eremotherium to extend right up to the Younger Dryas, as the remains of more common animals like mammoths, horses, and camels do.

Soldiering on

If there's one thing all scholars involved in this famously contentious debate would welcome it's more data. For in science, as Kennett put it to me, "data eventually rules." Grayson, for one, feels the field would benefit from a better understanding of just when each of those 20 rarer genera of big beasts went extinct. "Until we know when these extinctions occurred, I think we're wasting our time in trying to explain them," he says.

In the meantime, the dearth of widely convincing evidence only serves as a spur. MacPhee may be speaking for all researchers working on this mystery when he says: "What's of interest here for me personally is that these Pleistocene extinctions have occupied the minds of some very able thinkers over the last half century or so, and nobody's come up with anything that's drop-dead decisive. So it's attractive as an intellectual problem."

Granted. But hey, aren't you just dying to know what happened?

*Gary Haynes offered this sobriquet when I asked him if a playful term for the comet hypothesis had caught on yet.

The “Ultimate Jurassic Predator” Could Crush a Hummer in Its Jaws

On a Norwegian island within the Arctic Circle, researchers have unearthed the fossilized remains of a marine monster they call “Predator X.” The 50-foot beast is a new species of pliosaur, and researchers say the enormous reptile ruled the Jurassic seas some 147 million years ago…. “Its anatomy, physiology and hunting strategy all point to it being the ultimate predator – the most dangerous creature to patrol the Earth’s oceans” [New Scientist], the Natural History Museum at the University of Oslo said in a breathless press release.

Predator X swept through the seas some 147 million years ago during the Jurassic Period, when dinosaurs walked the land. The creature swam with its four flippers, and relied on its crushing jaw power to bring down its prey–lead researcher Joern Hurum estimates that its had 33,000 pounds per square inch bite force. Says Hurum: “With a skull that’s more than 10 feet long you’d expect the bite to be powerful but this is off the scale…. It’s much more powerful than T-Rex” [Reuters]. Hurum has said that a previously discovered fossil pliosaur was big enough to chomp on a small car. He said the bite estimates for the latest fossil forced a rethink. “This one is more like it could crush a Hummer,” he said [Reuters]. Hurum theorizes that the 45-ton predator feasted on fish and marine reptiles, including ichthyosaurs and long-necked plesiosaurs.

Paleontologists dug up the partial skull and the fragmented skeleton of a giant pliosaur last summer on the island of Spitsbergen. Fossil hunters get used to working in the heat and cold, the dry and wet, but even without counting the polar bears nosing around their dig, Spitsbergen posed unusual challenges. It has only a three-week window for excavating, from the end of July through much of August. That is after the warmth of a brief summer has thawed upper layers of the ground and before the onset of the round-the-clock darkness of Arctic winter [The New York Times]. A documentary about the expedition will be shown on the History Channel later this month.

The researchers haven’t yet given the new species a scientific name, and although they’ve described their findings at scientific conferences, they have yet to publish their work in a peer-reviewed journal–they say that will happen later this year.

Trio of Galaxies Mix It Up

Release No. STScI-2009-10
Image Credit: NASA, ESA, and R. Sharples (University of Durham)

Though they are the largest and most widely scattered objects in the universe, galaxies do go bump in the night. The Hubble Space Telescope has photographed many pairs of galaxies colliding. Like snowflakes, no two examples look exactly alike. This is one of the most arresting galaxy smash-up images to date.

At first glance, it looks as if a smaller galaxy has been caught in a tug-of-war between a Sumo-wrestler pair of elliptical galaxies. The hapless, mangled galaxy may have once looked more like our Milky Way, a pinwheel-shaped galaxy. But now that it's caught in a cosmic Cuisinart, its dust lanes are being stretched and warped by the tug of gravity. Unlike the elliptical galaxies, the spiral is rich in dust and gas for the formation of new stars. It is the fate of the spiral galaxy to be pulled like taffy and then swallowed by the pair of elliptical galaxies. This will trigger a firestorm of new stellar creation.

If there are astronomers on any planets in this galaxy group, they will have a ringside seat to seeing a flurry of starbirth unfolding over many millions of years to come. Eventually the ellipticals should merge too, creating one single super-galaxy many times larger than our Milky Way. This trio is part of a tight cluster of 16 galaxies, many of them being dwarf galaxies. The galaxy cluster is called the Hickson Compact Group 90 and lies about 100 million light-years away in the direction of the constellation Piscis Austrinus, the Southern Fish.

Hubble imaged these galaxies with the Advanced Camera for Surveys in May 2006.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA) and is managed by NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Md. The Space Telescope Science Institute (STScI) conducts Hubble science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington, D.C.

STScI is an International Year of Astronomy 2009 (IYA 2009) program partner.