November 29, 2006 3:36
Dino Killer: One Comet, not Many
Only 20 years ago, the notion that a giant comet or asteroid impact killed off the dinosaurs was still a radical theory, but the discovery of a huge buried crater at Chicxulub, on the coast of Mexico's Yucatan peninsula in the early 1990s proved that a strike from space was at least a major factor. The dust and debris thrown into the atmosphere from the impact would have cut off the sun, killing off plants at the base of the food chain, and chilled the planet dramatically to boot. But geologists have questioned whether a single space rock could have done the job itself, or whether multiple impacts were involved.
Nope--according, at least, to Ken MacLeod, a geologist at the University of Missouri-Columbia. Reasoning that sediments close to the impact site would be too churned up by the violence of the event to be useful, and that sediments too far away would contain too little debris to be definitive, he and several colleagues plumbed the seafloor about 2,800 miles away from the Yucatan. What they found was one and only one layer of impact-related material, dated to 65 million years ago--the precise age of the Chicxulub crater and of the dinosaurs' demise. His verdict: one shot from space was all it took.
November 29, 2006 1:01
Has Stradivarius' Secret Been Solved?
A rival publication which shall remain nameless published a piece yesterday describing the amazing new high-tech methods violin makers are using to try and reproduce--or even surpass--the extraordinary instruments made in Italy by the legendary Antonio Stradivari and Giuseppe Guarneri, in the 1600s and 1700s. The story is full of references to graphite fibers and such--things you'd expect to find in a jet, not a fiddle.
But the piece leaves out one crucial fact. The reason former racing-shell designers and the like are forced to invent new ways to make violins is that nobody to date has completely figured out why those 300-plus-year-old violins, made with simple hand tools from low-tech spruce and maple still sound better than pretty much any instruments made since. It's not for lack of trying: the secret of Stradivari and the others has been a matter of intensive investigation by luthiers, engineers and physicists for 100 years and more; the old violins have been taken apart and their pieces measured, calibrated and,vibrated at high frequency--with no agreement at all about what makes them tick, or, more accurately, sing.
Today, however, a report in Nature is proposing at least a partial explanation. The extraordinary resonance of the old Italian violins, says a team of scientists led by Joseph Nagyvary, a biochemist at Texas A&M University, is...biochemistry. By sending tiny slivers from several Stradivari and Guarneri instruments through a sophisticated mass spectrometer, they've found evidence the wood was treated before it was carved into violins.
What that treatment consisted of is left unspecified in the report--as is the fact that Nagyvary has been pursuing the Stradivarius mystery for more than 25 years, doing extensive research on the lumber business in Northern Italy centuries ago and on the finishes used by furniture makers in Cremona, where Stradivari lived and worked. In all that time, he's come up with some highly plausible theories--that the wood felled in Italian mountain forests was floated downriver and sat in Venetian lagoons for up to a year before being sold, absorbing the brackish waters (a chemical treatment, albeit inadvertent). And he's concluded that the varnishes Stradivari used may have been full of fruit sugars, giving the wood an especial stiffness that allows it to vibrate brilliantly.
He's also been making violins according to his theories, and using sophisticated sound equipment to compare their sound with the real thing. And in a number of blind tests with real musicians and real audiences, Nagyvary's violins have equaled or even surpassed those of the Italian masters.
And there's not a drop of graphite or epoxy or space-age plastic in them.
November 29, 2006 9:07
Got Milk? OK, Let's Go to Radiology
People with abdominal pain are often given CT scans to see if there's something amiss with the intestines. But since the scans have trouble seeing soft tissue, the patients have to drink a "contrast agent" which shows up bright on the images and helps radiologists figure out where the intestines stop and other organs begin. The standard drink of choice is an artificial liquid, often containing barium. (One popular brand's marketing slogan: "Positive enough to mark the bowel...negative enough to make a difference!" Can't you just feel the excitement?)
Nobody likes drinking the stuff, though--but according to a report delivered at this week's annual meeting of the Radiological Society of America in Chicago, it might not be necessary. Dr. Lisa Shah-Patel, of New York's St. Luke’s-Roosevelt Hospital, you can achieve comparable results with nothing more exotic than milk. In a study comparing moo juice with the artificial stuff, milk highlighted the small intestine nicely, caused fewer side effects (cramping, diarrhea), and cost about a tenth as much. And if the radiology department is out, they can send an orderly over to the 7-Eleven for more.
November 20, 2006 12:01
Sweet Young Things? No Thanks, I'm a Chimp
The films Must Love Dogs and Something's Gotta Give were marketed as romantic comedies, but plenty of women thought they should be filed in the fantasy aisle at the video store. That's because in both cases, the middle-aged and beyond-middle-aged male leads threw over sexy 20something women for more age-appropriate mates. It never seems to happen that way in the in the real world--or rarely enough, anyway, that older men with young trophy wives are a cliche, and vice versa is emphatically not.
Men in the real world acquired a biological defense for their behavior over the past decade or so in the form of evolutionary psychology, which claims that our basic behaviors evolved just like our ear lobes did, through natural selection. In this case, the argument goes that as our species developed, women favored mates with the social clout to protect their offspring from harm; men preferred mates who were young and healthy and could produce the most offspring--and the ones with clout got their pick. Others have suggested that since humans form long-term pair bonds, and because women stop being able to have children at menopause, it's more appealing to a man who wants to procreate to seek out the youngest fertile females, who can keep it up longer.
It all makes sense--until you read the cover story in the latest issue of Current Biology. It turns out that chimps, our nearest living relatives, don't act that way. By studying chimps at Kibale National Park in Uganda, biologists from Harvard and Boston University were able to show that older females were the most popular partners for copulation. It seems to fit in with the second of the two explanations above: chimps don't form long-term bonds, and they don't go through menopause.
November 17, 2006 8:26
Einstein's Revenge
It was a huge surprise back in 1998 when two sets of astronomers, peering deep into the universe, found that the cosmos isn't just expanding--it's actually speeding up. Some mysterious force must be causing this unexpected acceleration, and given their unusual talent at coming up with cool-sounding terms that sound like they belong in Star Wars or Star Trek (dark matter, black holes, quasars, pulsars, the Big Bang) it isn't surprisng that they did it again: Dark Energy is what they decided to call it.
What it actually was remained a mystery, though. A leading contender was something Einstein dreamed up early in the last century and then repudiated: a sort of antigravity that pervades all of space, through all of time. It's known as the cosmological constant--and it should have had just the effect the observers finally saw in 1998. But it might also be something else--some other force that wasn't constant at all, but might appear, disappear, even reverse direction as time went on. When I wrote this 2001 cover story on dark energy the jury was still out.
But now Adam Riess, of the Space Telescope Science Institute, one of dark energy's original discoverers, has announced new evidence in favor of Einstein's version. By looking at how fast supernovas, or exploding stars, at the very edge of the observable universe are flying away from us, he and his collaborators have been able to show that the dark energy was present as early as nine billion years ago. In a less-than-14-billion-year-old universe, that's close enough to the beginning to suggest that dark energy really is very much like Einstein's cosmological constant, and not much like the other suggested ideas.
November 16, 2006 11:16
Neanderthals and Us
A few weeks ago we ran a cover story that addressed the question of what makes us different, at the genetic level, from the chimps, our nearest living evolutionary relative. But we also talked about an ambitious attempt to sequence the genome of our nearest relative, living or dead: the Neanderthals, who disappeared from Earth as recently as 20,000 years ago. We talked about research that was soon to be published--and "soon" is now.
According to papers appearing in Science and Nature, the partial sequencing done so far suggests that that the last common ancestor of modern humans and Neanderthals lived about 700,000 years ago, and that the two lines split into distinct species about 370,000 years ago (according to the Science paper, or more like 500,000, says the Nature team, using different techniques; the estimates are loose enough in both cases that the two teams of scientists involved don't consider them inconsistent). Another finding, which is always good for a titillating headline, is that there's little evidence for interbreeding between us and the Neanderthals. Although finding there was would be even more titillating, in a grotesque sort of way.
Anyway, this is just the beginning of what promises to be a flood of new information about Neanderthals coming out of the sequencing project. So watch this space...
November 12, 2006 4:06
The Secret of Comedic Success
Lesser minds may be trying to cure cancer, or plumb the secrets of the atom, or figure out how to stave off global warming. Anthony Little, a psychologist at the University of Stirling, in Scotland, has more important things on his mind. He has come up with a computer simulation, based on 179 features from 20 top comedians, of the "perfect comedy face."
This being a simulation, there's nobody who actually has the perfect funny face. But you can evidently measure the funniness quotient of actual humans to see how they measure up. This being a U.K. study, the examples he offers up may not be terribly familiar to Americans: David Cameron, the British Conservative Party leader, is more amusing to look at than Tony Blair. Another face that will prime you to giggle, according to the Stirling press release: Manchester United star Wayne Rooney and celebrity chef Jamie Oliver. Whoever they might be. Of course, having the perfect comedy face is most important for comedians--and the one who comes closest, evidently, is Ricky Gervais. Whoever he is.
As to specifics, Little is quoted as saying ""The characteristics of a feminine face imply that the person may be agreeable and co-operative, which can be causal in our first impressions of comedians as being friendly and funny." Or, as Gervias told the BBC: Ricky Gervais said: "All these years I assumed my global success as a comedian was down to my acute observations, expert directorial rendering and consummate skills as a performer.Turns out it's because I've got a fat girly face."
November 10, 2006 8:52
Weird Storm on Saturn
Jupiter's Great Red Spot is often described as a permanent, hurricane-like cyclonic storm--but unlike a real hurricane, it has no eye, the towering fast-rotating cylindrical wall of cloud that surrounds a core of calm. But now scientists working on the Cassini probe, which has been swinging around Saturn since 2004, has discovered a storm on the solar system's second-largest planet that does have an eye. You can see a movie of this truly hurricane-like maelstrom here (but if you have trouble loading it, go here).
This being Saturn, you wouldn't expect the storm to be exactly like a hurricane on Earth, of course, and it's not. On Earth, these storms form at mid-latitudes and move with the prevailing winds. This one sits directly over Saturn's south pole, and doesn't seem to move at all (but scientists will have to watch it for the next few months to make sure). And with winds reaching 350 m.p.h., Saturn's storm is twice as powerful as a Category 5 hurricane--unless global warming really kicks off, that is.
November 9, 2006 4:27
Let's Party Like It's Y2K All Over Again
Remember Y2K? For anyone who doesn't--or who'd rather forget that tale of impending doom nobody knew whether to take seriously or not--it had to do with the fact that programmers in the 1950s foolishly set things up so that computers recorded years as two digits. So when midnight arrived on Jan. 1, 2000, went the theory, computers would think it was 1900. The resulting electronic mayhem would cause planes to fall from the sky, bank records to evaporate and generally result in the end of civilization as we knew it.
Or something like that. The 1990s geeks took care of the problem (if it really was a problem) in plenty of time, though. And the only lingering memories of the dreaded day were leftover Y2K emergency candles and the fact that we now enter dates on forms and websites as MM/DD/YYYY.
Except, evidently, at NASA. According to the Associated Press, the shuttle Discovery is being pushed out to the pad in a hurry so it can go into space, complete its 12-day mission and return before Jan 1. And that's because the clocks built into the shuttles' computers are not capable of turning over from one year to the next. It turns out that no shuttle has ever been in orbit on New Year's Eve so far--and the agency doesn't look forward to seeing what might happen if it does. "We've just never had the computers up and going when we've transitioned from one year to another," Discovery astronaut Joan Higginbotham told the AP. "We're not really sure how they're going to operate." The astronauts are sure that even if they do end up stuck in space due to some unforeseen delay in coming down, they'll figure something out.
But it does make you kind of scratch your head that the possibility even exists.
November 8, 2006 9:28
Don't You Just Love Pigeons?
No, you probably don't. If you live or work in New York City, the phrase "rats with wings" will be all too familiar, and that probably applies if you live or work in any city in the U.S.. Most likely it also applies, suitably translated, if you have anything to do with cities, period.
It's understandable. Unlike rats without wings, pigeons don't carry awful diseases like the plague; they don't bite people; and they don't skulk inside the walls of your apartment or inside your garbage cans. They pretty much just walk along the sidewalks with that goofy head-bobbing thing they do, pecking at bits of food or things that might be, and make cooing noises. Nobody says "let's go to the park and feed the rats," but you hear it all the time with pigeons. Their awful reputation comes from their numbers and, most of all, from their tendency to...let's say "defecate" over every possible surface, including people who happen to be walking underneath when the birds are on the wing and the call of nature comes. I have my own story, which I've told enough times that my family is sick of it. Email me for details.
Anyway, I hated pigeons too, until I read a terrific new book, appropriately enough titled Pigeons: The Fascinating Saga of the World's Most Revered and Reviled Bird, by Andrew D. Blechman. (I should tell you that I know Blechman peripherally; he went to a high school where I have lots of family and personal ties, though I can't be certain I ever spoke two words to him directly). I tend to be cynical about books like this with one-word titles and grandiose subtitles. (You know the type-- "Cheese: The Fermented Dairy Product that Toppled Empires"; "Elastic: The Twangy Stuff That Transformed Underwear Forever." I leave it as an exercise for the reader to decide whether these particular versions of that badly overworked, copycat genre are real).
But even though I approached this book with real cynicism, I have to admit, it's a great read and lots of fun. Blechman reminds us that the birds are actively beloved by the thousands of people who keep and race homing pigeons (the character of Detective Bobby Simone, of NYPD Blue, was one, as were many characters in movies that slip my mind). But he also tells us things we probably never knew--that pigeons were among the first animals domesticated by humans, maybe 10,000 years ago, mostly for food--and that they're still considered a delicacy in many parts of the world. Most of the wild pigeons that deface...I mean, walk our streets are descended from birds bred in captivity. Nearly a million pigeons carried messages in the two World Wars, and, he says, saved thousands of lives (of Americans and their allies, anyway).
The book is filled with this sort of fascinating detail, along with visits to pigeon breeders (and even a breeder's convention), biologists who specialize with the birds and more. It's great for cocktail-party conversation and once you read it, to use a badly cliched phrase, you'll never look at pigeons the same way again.
Or maybe you will, in which case you'll appreciate that Blechman also takes on the question of pigeon control, claiming that poisoning, starvation and other harsh methods don't keep populations down; they actually encourage the beasts. But in Europe, anyway, much more humane methods (like building nesting areas that draw them away from public places) can reduce populations dramatically.
In short, there's something for everyone.
November 7, 2006 9:23
A Silent Jetliner
I spent a couple of nights at a hotel only a half-mile or so from Chicago's Midway Airport last week. Not a serene experience, believe me. So I was intrigued to learn that a team of engineers from MIT and the University of Cambridge, in England, with input from some 30 private companies, has been working for several years now on something called the Silent Aircraft Initiative. The first public presentation of their proposed design for a 215-passenger plane comes today, at a press conference in Cambridge.
For anyone who doubts a plane can be literally silent, keep doubting. If that's what the scientists were actually claiming, you could rightly dismiss them as complete cranks. But what they do claim is still pretty dramatic: their new plane, which they believe could be in the air by 2030, would make takeoff and landing "almost imperceptible outside the perimeter of an airfield in an urban environment." Like Midway.
One of the key features that make this possible are a shape that makes the whole plane a lifting body, which means the fuselage as well as the wings produce lift. That allows slower takeoff and landing speeds, which cuts noise. Another is that the engines are embedded in the plane, not hanging from the wings, with air intakes on top of the fuselage; any noise they make is shielded by the body of the plane, so much less reaches the ground.
As an added bonus, say the designers, this new aircraft is about 25% more fuel-efficient than comparable planes.
I, for one, can hardly wait. And while I haven't polled them, I suspect the many hundreds of thousands of people who live near major airports would agree.
November 3, 2006 9:41
Your Neanderthal Heritage
Paleontologists have gone back and forth over whether humans and Neanderthals ever interbred (actually, Neanderthals were humans too, just a different species). Some fossil skeletons have been discovered that argue in favor of that rather racy idea, while genetic analysis suggests otherwise.
Now Erik Trinkaus, a paleoanthropologist at Washington University has re-examined and re-dated some fossils found in 1952 in a Romanian cave, and proclaimed that they represent an early modern human from about 30,000 years ago, but with certain physical features that suggest a partial Neanderthal ancestry. This, say Trinkaus and his colleagues, demonstrates that there was a "complicated reproductive scenario" between the two species. They further argue that the competing idea--that humans simply shoved Neanderthals aside and into eventual extinction--should be abandoned.
Not too likely: Scientists rarely fold their intellectual tents and go away just because their competitors tell them to. It's tantamount to Republicans telling Democrats they might as well dissolve the party. Nice try, though.
About Eye On Science
TIME contributing writer Michael D. Lemonick fills you in on what's hot, what's cool, what's controversial and what's just plain silly in the world of science. Comments encouraged.
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