August 28, 2006 9:52
This Week's Cosmic Cover Story
Normally TIME cover stories talk about the current news of the world; this week we're talking about news from the edge of the universe, and while it's current in one sense, it's more than 13 billion years old in another. If you want to find out how the very first stars were born, lighting up a universe that had been dark for hundreds of millions of years, go here and you'll understand astronomers' best understanding to date, and discover what new, giant telescopes will tell us to firm up that understanding (or of course you can also find it on newsstands this week).
This story was especially rewarding to report and write because observations of the very edge of the universe are usually made from space telescopes like the Hubble and the Spitzer. But I was lucky enough to learn, just as I thought my reporting was winding down, that a Caltech astronomer named Richard Ellis and his grad student, Daniel Stark, were going to be using the mammoth Keck Telescope in Hawaii to do their own search--and that I was welcome to come along. Not too many years ago, that would have meant going to the top of Mauna Kea, an extinct, nearly 14,000-ft. volcano, where the telescope sits in frigid, dangerously thin air--exciting, otherworldly and really really uncomfortable. But now astronomers usually observe from Keck headquarters in the town of Waimea, some 20 miles away and two miles lower in altitude. Much nicer.
Even better, Ellis and Stark were trying something audacious: looking for galaxies so dim and so far away that in theory they're impossible to see with the Keck. But Ellis had figured out a way to do so anyway, or so he claimed. Was he right? If you read the story, you'll find out--and also find out what it's like to be at one of the world's most powerful scopes with one of the world's most prominent stargazers.
August 25, 2006 2:13
Pluto...The Day After
Now that the dust has settled in Prague and the astronomers assembled for the International Astronomical Union's big meeting there have departed, it's time for a few parting thoughts about the drama, settled just yesterday, over what in our solar system counts as a planet, and what doesn't. Nobody is unaware by now, I'm sure, that Pluto doesn't count any more. In response to a motion put before the IAU's General Assembly, the gathered stargazers voted overwhelmingly to reclassify Pluto as a dwarf planet instead, a new category that will also include Ceres, largest of the asteroids, and 2003 UB313 a Pluto-like object, a little bigger than Pluto and farther out, announced last summer.
It astonished me, frankly, that the general public followed this story so closely, and cared so much about the outcome. Newspapers were filled with quotes from ordinary folks weighing in on what a tragedy it was--things like "poor little Pluto, he was my favorite." I'm not talking about schoolchildren, mind you, though they said this sort of thing too--these were adults.
But with all respect to their feelings (about a planet??? ok, sorry), here's my guide to thinking about the decision.
WHY IT'S GOOD:
1. It rights a historical error. When Pluto was first discovered, it was during a search for the mysterious Planet X that was distorting Uranus' orbit. But the distortions didn't actually exist; they were the result of imprecise measurement. Beyond that, Pluto was originally believed to be as big as the Earth, making it a planet for sure. Except it's really smaller than our Moon, and smaller than a half-dozen other moons as well.
2. It was tiny, but for the first 40 years after Pluto was found it was the only object known out beyond Neptune except for the comets. And while it was a lot smaller than the other planets, it was gigantic compared with a comet. But now we know that there are thousands of objects out there, some nearly as big as Pluto, and at least one that's bigger--and, like Pluto but unlike the planets, they're all made mostly of ice. Pluto is a very large member of a class of objects that aren't like planets. So calling it a planet isn't really a scientifically useful way to categorize it. This way is better.
3. Schoolchildren might not be happy, but the point of teaching science, as some people too easily forget, is not to create happiness but to explain how the world works, and how we know. This change provides an incredibly valuable teaching moment. When a child asks "why did they pick on poor Pluto," the answer will tell them something new we've learned about the universe, and how we learned it. Science is about discovery, not about memorizing lists of things.
4. The debate in Prague--and it was vigorous--proves that science is a human enterprise that includes passion and politics. The original definition of planet, which included Pluto and three other objects, was soundly rejected by the delegates, who demanded something more scientifically valid. But not everyone was happy: Alan Stern, who (coincidence?) is principal scientist on the New Horizons mission, on its way to Pluto right now, told the New York Times the decision was "scientifically sloppy and internally inconsistent." Another teaching moment: scientists don't always agree.
WHY IT'S BAD
The only reason I can think of is one suggested to me by a friend: we can no longer use the mnemonic " My Very Energetic Mother Just Served Us Nine Pizzas" to remember the planets in order out from the Sun. My solution: Change "Nine Pizzas" to "Nachos." Problem solved.
August 24, 2006 10:35
About Pluto....Oops.
I'm sure nobody remembers this far back (yeah, I wish), but last week I prematurely shouted that "Pluto's In!" A new definition of the term "planet"--well, actually, the only actual definition since the Greeks first used the word to describe objects that wandered through the sky against the fixed backdrop of stars--meant Pluto, subject of much debate, would retain its formal status as the ninth planet of the Solar System.
I should have said this was a proposed new definition. A committee of the International Astronomical Union had agreed that "planet" should refer to any object that is massive enough to be squeezed into spherical shape because of its gravity and which doesn't orbit another planet. That would have added three new planets to the existing nine.
But astronomers at the IAU's meeting in Prague reacted vehemently against this idea--it would have made Charon, Pluto's moon, a planet (why, you ask? because the center of mass of the Pluto-Charon system lies out in space, whereas the center of the Earth-Moon system is below the surface of the Earth--a loophole so ridiculous it turned everyone off). And it would have opened the door for dozens of objects not named in the first cut to be planets--asteroids and Pluto-like objects that are just a bit smaller)--as soon as the paperwork could be arranged.
So the committee hurriedly went back into session to come up with a new definition and it was just adopted an hour or so ago by majority vote of the thousands of scientists in attendance. A planet, says the IAU (and they're the ones who get to decide), is "a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit."
This last clause, meaning a planet's gravity has slingshotted everything else out of the neighborhood, knocks Pluto off the list: its orbit overlaps with Neptune's (Pluto's orbit is so elongated that it's sometimes actually closer to the Sun than Neptune is), and it sure hasn't cleared Neptune away. Of course Neptune hasn't cleared Pluto away either--but if they ever had a close encounter it would, trust me.
That leaves the asteroids out too, since thousands of them share an orbit, more or less.
So what is Pluto? The IAU has created a new category, called "dwarf planet" (sort of like an honorable mention) for objects that meet criteria a) and b) above, but not c). Pluto, the asteroid Ceres and 2003 UB313, the object discovered last year, similar to Pluto, but bigger, will all go into the new category.
So Pluto is not in. Pluto is out (why do I feel like Heidi Klum on Project Runway?) or at least half-out.
I do have to needle my colleague at the Associated Press for this one very strange line in his otherwise terrific report from the conference. "It was unclear how Pluto's demotion might affect the mission of NASA's New Horizons spacecraft, which earlier this year began a.... journey to the oddball object to unearth more of its secrets," writes William J. Cole. I'm just trying to imagine what he thinks could possibly change--NASA will tell it to turn around and come back, or what?
August 23, 2006 2:45
End Run Around the Stem-Cell Ban?
As we've noted many times, scientists looking to develop stem cells into powerful therapies against an enormous number diseases ranging from diabetes to Parkinson's have been utterly frustrated by the Bush Administration's ban on federal funding. According to that policy, they can only use federal dollars on the handful of stem cell lines in existence at the time Bush's policy went into effect in 2001--a pitifully small, very finicky source.
So far, scientists have responded in several ways. Some are trying to use adult stem cells, which may or may not turn out to be effective; others are using the state funding that's arisen in response to Bush's policy; still others have just given up and gone to countries, like China or Singapore or Britain, that have a more enlightened policy.
But a little more than an hour ago, the American company Advanced Cell Technology reported in Nature that they may have a way to start up stem cell lines in a new way that could ultimately make non-federal research easier. By taking a single cell out of the seven or eight that make up an embryo at its earliest stages, they've left the embryo intact but managed to create stem cells from the one they removed. No embryo is destroyed in the process, which is one of the key no-no's in the Bush policy.
It's actually not news that you can safely remove a cell from an embryo. It's done all the time in a procedure called pre-implantation genetic diagnosis. The idea is that parents known to be carrying a potentially dangerous gene--for Tay-Sachs disease, say--do in-vitro (a.k.a. test tube) fertilization. One cell is removed, it's tested for genetic problems, and if there are none, the embryo is implanted and fertilization goes ahead.
So scientists at ACT took a cell and tried to coax it into becoming a stem cell colony. Turned out it wasn't so easy, and in the end they had to use "feeder cells" from mice to nourish the human cells, and add other human stem cells to coax them to grow. That introduces contamination that makes the new line essentially useless for potential therapies. Dr. Robert Lanza, who did the research, thinks they can overcome these crutches: the embryos they used were frozen specimens that had been originally created for preimplantation diagnosis; fresh embryos might well be easier to work with. And while other scientists are very cautious about a full-fledged endorsement before others have replicated ACT's work, Dr. Arnold Kriegstein of the University of San Francisco’s Institute for Regeneration Medicine says: “It looks quite impressive. If it holds up, I think it has the promise of being a very significant advance in the field.”
Important note: this entry is based on reporting by Alice Park
August 22, 2006 11:10
Math Prize? A Million Dollars? Yawn...
Grigory Perelman already has a well-earned reputation for brilliance and for what most people would consider very odd behavior. The reclusive Russian mathematician has, by all accounts, proven something called the Poincare Conjecture, a problem in topology that has resisted solution for about a century.
That's the brilliant part. The odd part is that Perelman is evidently completely uninterested in a $1 million prize reserved for the person who proves the Poincare--one of seven so-called Millennium Problems identified by the Clay Mathematics Institute. He's also uninterested in any publicity whatever about his work. Perelman generally refuses to talk to the press, and when England's Sunday Guardian newspaper managed to corner him a couple of days ago at his mother's house in St. Petersburg where the currently unemployed mathematician lives, he told them ""I do not think anything that I say can be of the slightest public interest."
Today's news just adds to his legend--both sides of it. The brilliant side has been further polished by a decision by the International Mathematical Union to award Perelman the Fields Medal, the equivalent of a math Nobel (John Nash, with his beautiful mind, never quite managed to win it). And with almost predictable oddness, he isn't going to accept it. Indeed, reports the Russian ITAR-TASS news agency, Perelman has declared that he has “ditched mathematics, since I have disenchanted in it" (it's unclear whether the broken English is Perelman's or comes from ITAR-TASS, which also called the problem he solved the "Puankare hypothesis."
August 21, 2006 2:33
Want Some Proof Dark Matter Exists?
Credit: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.
Most astronomers accept the existence of dark matter--some mysterious stuff, never actually seen and still unidentified, whose gravity holds together individual galaxies and keeps clusters of galaxies from flying apart. But it's also possible that gravity itself behaves in ways we don't understand; if so, the gravity from what we can see--stars and gas clouds, mostly--might be enough to do the job itself.
The image above casts plenty of doubt on that second idea. What you're looking at is a huge cluster of galaxies known as 1E 0657-56, which was formed in the titanic collision of two smaller clusters. The individual galaxies are pretty much unscathed--they're too far apart to make it likely that they'd hit each other (you can see them as the bright objects scattered through the image--these things are very far away).
You also see bright blobs, two pink and two blue. The pink is intergalactic gas, heated up as they passed through each other during the collision so they now glow in X-rays, which were picked up here by the Chandra X-ray satellite. The blue blobs aren't direct images at all, but rather "maps" of where concentrations of mass are greatest in the system. They were made by looking at distortions in background objects, even further away than the colliding clusters, caused by foreground gravity. This "gravitational lens" effect was first predicted by Einstein, and is now used in all sorts of astronomical research.
So what happened is pretty clearly this: you start out with two separate clusters, each with a lot of galaxies, a lot of gas, and a lot of dark matter. They run into each other. The galaxies continue along their original path, unscathed. The cloud of dark matter does too, because it's made, most likely, of particles that don't interact with each other or with regular matter. But the gas from each original cluster lags behind; the same friction that heated it up in the collision slowed it down.
So by separating the hot gas from the dark matter, this collision made it clear that the dark matter is really there. And it let NASA take a very cool picture.
August 16, 2006 2:01
Pluto's In!
For more than a year now, astronomers have been fretting about whether Pluto should be considered a planet or not. It's a decade-old controversy: Pluto is so much smaller than the other eight planets, so different in composition and in such a weird, tilted orbit that it doesn't quite belong--but the discovery last summer of a new object, similar to Pluto but bigger, threw the whole thing wide open. If Pluto is a planet, so must 2003 UB313 be (it hasn't been named yet). If 2003 UB313 isn't, Pluto can't be. Simple as that.
Except that to make such a decision, the International Astronomical Union would have to define exactly what "planet" means. "I know one when I see one" isn't good enough any more. Hammering out that definition has proven extraordinarily contentions. But the IAU committee in charge of figuring it out has just announced that it's reached a consensus. In a bulletin from the groups annual conference, in Prague, the IAU has made public its draft definition: " A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet."
If that definition is approved by the group's general assembly later this week, it becomes official. And instead of the nine planets we all grew up with (all of us who grew up after Pluto was found in 1930, anyway), the solar system will have 12: Mercury, Venus, Earth, Mars, Ceres (it's currently classified as an asteroid, although it was considered a planet when it was found in 1801), Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313
But...wait a minute. Charon is a moon of Pluto, which should disqualify it. But no, it gets in under a loophole. Every moon and its planet orbit each other, technically, swinging mutually around a common center of gravity. In every case but this, though, that center of gravity is within, though not at the very center of, the planet. Charon and Pluto's center of gravity is much closer to Pluto, but still out in space. Ergo, says the IAU, it's a double planet.
That Talmudic distinction is already driving astronomers nutty, as is the fact that plenty of other objects, already discovered in the wide reaches out past Pluto, should presumably also qualify, but haven't made the list. Not to worry, says the IAU. The list of 12 is expected to grow.
August 14, 2006 11:26
Greenland Melting
A few months ago, we brought you news that several of Greenland's glaciers had sped up considerably in their rate of flow out to the sea. The best explanation was that meltwater on the surface was percolating down through cracks to act as a lubricant, letting the rivers of ice slip along across underlying bedrock. The meltwater itself was quite likely caused by global warming, but dumping more glacier per year into the ocean would amplify the rise in sea level that would be occurring anyway.
Now comes a study in Science showing that the overall rate of melting on Greenland's ice cap is indeed speeding up. The data come from a remarkable pair of satellites, collectively called GRACE, which orbit the earth in tandem. When they pass over an area with something more or less than the average concentration of mass on the surface--a mountain range, say, or a crater--the tiny bit of extra gravity or diminished gravity they feel makes them change position with respect to each other by a fraction of an inch. It was this technique that allowed the satellites to discover an unsuspected impact crater under Antarctica's ice recently (less gravity in this case), and now repeated passes over Greenland over the past few years show that the gravity of that huge island is getting progressively lower.
That's clearly due to mass loss in Greenland's massive ice sheet, which is clearly due to melting. Once again, the uncertainties about climate modelers' predictions of what global warming will bring--uncertainties touted by those determined to pooh-pooh the danger--are being resolved, and not in a happy direction.
August 10, 2006 2:11
More Bad News from Antarctica
Climate modelers have long predicted that global warming would begin at some point to start melting the ice shelves that surround Antarctica--and sure enough, that process appears to be well under way. But the resulting rise in sea level would be mitigated somewhat, they further argued, by increased snowfall in the continent's frigid interior. In a warmer world, more water should be evaporating from the seas, leading to more precipitation.
In that prediction, alas, they seem to have been wrong. The most exhaustive study of Antarctic precipitation ever conducted, as reported moments ago in Science shows that Antarctic snowfall hasn't increased in any measurable way over the past 50 years. That doesn't necessarily mean it's not happening at all--but if it is, the change is too small to detect.
It's no surprise that some of the modelers' predictions are wrong, of course: the climate is too complex to be predicted in exhaustive detail, even with the most powerful computers on the planet. And indeed, it's the uncertainties in the models that global warming critics so often point to to try and shoot down the theory. What the critics haven't been able to answer is the fact that if the models were completely bogus, they'd be wrong equally often in both directions--that is, in over-predicting the dangers of warming and in under-predicting the factors that might keep it under control.
So how come the errors mostly end up underestimating the downside?
August 4, 2006 5:57
Now For Something Truly Bizarre
I hardly know what to make of this one. A biological scientist from the U.S. Geological Survey--of all places--have published a paper in the Proceedings of the Royal Society, Biology, suggesting that human culture may be significantly influenced by a parasite that commonly infects cats, but also targets humans. "In populations where this parasite is very common, mass personality modification could result in cultural change," says the scientist, Kevin Lafferty, who's based at the University of California, Santa Barbara in a press release, variations in the prevalence of Toxoplasma gondii "may explain a substantial proportion of human population differences we see in cultural aspects that relate to ego, money, material possessions, work and rules."
It sounds like an absurdly grand claim, but toxoplasma, a protozoan, is such strange organism that it might not be entirely crazy. When the parasite infects the brains of rats and mice, it alters their behavior, making them more reckless than normal--reckless enough that they don't avoid cats the way good sense would dictate. As a result, they're devoured, at which point the micro-organisms are able to reproduce--something they can only do in felines. Then their eggs are excreted, and any mammal that eats something contaminated with the cat feces takes up the toxoplasma eggs. A rat, for example, who then begins to act reckless...and so on.
Humans eat toxoplasma too, in such things as unwashed vegetables; the worst affected are pregnant women, whose embryos can suffer from birth defects, and the immunocompromised--AIDS patients, for example, or those on chemotherapy. The rest of us might experience nothing more than mild, flu-like symptoms, no more.
But while we don't go running out to find a mountain lion or other big cat to play with, it could well be that humans experience subtler behavioral changes than a rat would--a mild increase in the tendency to be adventurous, say. And because toxoplasma infection is actually quite common in humans, and varies from one region to another--about a third of Americans show antibodies to the parasite, but in Brazil the number rises to nearly 70%, while in South Korea it's under 5%. And those differences, suggests the study's author, could explain, at least in part, why people from different nationalities have developed differently along cultural lines. Lafferty acknowledges there are all sorts of factors that contribute to such traits, but argues that this tiny parasite could be one of them. And, he says, it's not necessarily a bad thing since, as he notes in the release, it adds to cultural diversity.
But it's a little horrifying that cultural diversity could be a symptom of parassitic infection. Or maybe that's just me.
August 3, 2006 11:34
Heat Wave: Global Warming or Not?
The Northeast is finally about to get out from under the crushing heat wave that has driven temperatures up over 100, setting one record after another this week and forcing the lights of Times Square to go dim as electricity for air conditioning took precedence over other uses. California should cool a bit too, after temperatures reaching as high as 112 killed more 100 people over the past two weeks. Europe is still suffering from its own spate of record temperatures, which are now threatening water supplies.
The inevitable question: Is global warming rearing its ugly--to say nothing of sweaty--head?
Extremists on both sides of the debate will be happy to give you a definitive answer. Yes, it's global warming, no question, say militant environmentalists. Nonsense, say the rejectionists. Global warming is not caused by human activity, heat waves are normal, give it a rest (last night on his syndicated radio show, the belligerent right-wing talk-show host Michael Savage declared that the warming already measured is due to hydrothermal vents on the ocean floor--a particularly clueless and desperate attempt to shoot down the scientific consensus).
The truth is that heat waves in the summer are normal. Some are worse than others. Therefore, no one heat wave--even a bad one, even one that strikes several parts of the world more or less at once--is proof of anything. But that doesn't mean this heat wave isn't a sign of global warming nevertheless. What climatologists have been saying ever since I wrote TIME's first cover story on global warming way back in 1987, is that there will never be a specific smoking gun for human-induced climate change. What will happen, they said, is that certain kinds of events--stronger hurricanes, heat waves, droughts, melting glaciers, disruptions of normal weather patterns--will gradually become more common and more severe. Any one of these things is likely to take place just from the natural ebb and flow of weather patterns. But in a gradually warming world, they'll happen more and more often.
So while it's true that 1944 was one of the 20 hottest years on record, the other 19 have happened since 1983. That's clearly a trend. And if the vast majority of climate experts are right, it's only the beginning. Next summer may not be especially hot--but over the next several decades, expect more and more heat waves like this one--and a few that are even worse. Expect them to show up more often, last longer and affect larger areas. And expect those other signs of warming--the storms, the droughts, and even such counter-intuitive events as the unusually harsh, snowy winter now going on in South Africa--to come along more often and be more severe as well.
That could lead to serious disruptions to our economy and our lives--especially, as some have argued, if the increasing use of air conditioners ends up pumping even more greenhouse gases into the atmosphere, bringing on the warming even faster. One possible outcome is a reverse migration within the US away from the Sunbelt back to the northern plains and the northeast, were the heat won't be quite so severe. What that could mean for American life and politics is anybody's guess--although one quasi-political figure has already changed his tune. Pat Robertson, the Christian broadcaster, former presidential candidate and longtime global-warming skeptic announced today on his talk show, The 700 Club, that the current heat wave has convinced him the threat is real, and that we need to cut back on the burning of fossil fuels.
August 2, 2006 7:41
Kansas Flips Again on Evolution
Watching the evolution wars in Kansas is like watching a tennis match, and the ball just went back over the net. The latest state school board election has put conservatives, who were skeptical about that newfangled theory called "Evolution," back in the minority, 4 votes to 6, after gaining the majority last year, after losing it in 2001, after gaining it in 1998. Every time the conservatives come into office, they change state education standards to downplay Darwin's theory--one board member who lost her bid for re-election this time called evolution "a fairy tale."
The Seattle-based Discovery Institute, meanwhile, which bills itself as a think tank but is actually a distortion factory continues to try and fool the gullible into thinking there's any actual scientific challenge to evolution (their favorite misleading catchphrase: "Evolution is a theory, not a fact," which plays on the public's misunderstanding of the word "theory.")
So once again, kids in Kansas will be taught actual science rather than a religious-based distortion of science. For the next year, anyway. For TIME's account of the last battle in the evolution wars, go here.
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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