Michael D. Lemonick

A stunning sighting around a nearby star offers a glimpse of our own solar system billions of years ago

With some 2,000 planets now known to orbit stars beyond the Sun and thousands more in the can waiting for confirmation, the once-exotic term “exoplanet” is so commonplace it requires no definition for many people. The term “exocomet,” by contrast, is a bit more obscure. Astronomers have known for years that comets orbit other stars—in particular, the relatively nearby star β Pictoris, which lies about 63 light-years from Earth, in the constellation Pictor.

But a new paper in Nature is more than a little mindblowing nevertheless. A team of astronomers is reporting the detection of nearly 500 individual comets that passed in front of β Pictoris between 2003 and 2011. And that’s not even remotely a complete sample. “We had only a couple of nights of observing time per year,” says lead author Flavien Kiefer, now at the University of Tel Aviv. “If we’d been looking constantly, we would have seen many thousands.”

There are a lot of reasons all of this seems slightly crazy. To start with, there’s the notion that you can see something as relatively tiny as a comet from nearly 300 trillion miles away. And in fact, you can’t. But when comets approach the heat of a star, some of their substance boils off to form an enormous cloud of gas and dust, and sometimes a tail as well. And when that cloud moves in front of the star, it distorts the starlight in ways you can see with sufficiently powerful instruments.

In this case, the scientists used the High-Accuracy Radial-Velocity Planet Searcher (HARPS), located at the European Southern Observatory, in Chile. As the name implies, it was designed to find planets—and it has. HARPS does so by looking for subtle changes in starlight created as the star wobbles in response to an orbiting planet’s gravitational tug. The distortions caused by an intervening comet are different, but HARPS can find those too.

The technique isn’t easy, says Aki Roberge, an astronomer with NASA’s Goddard Spaceflight Center, in Maryland who has studied β Pictoris as well, and who wrote a commentary in Nature on the new results, but it clearly works. “We always knew this would be a powerful technique,” she says, “They’ve done a really amazing job.”

The sheer number of comets also seems unlikely at first, until you realize that β Pictoris is extremely young—about 22 million years old compared with the Sun’s 4.6 billion. If we could see our own Solar System at that age, it wouldn’t look all that much different: a thick disk of gas and dust surrounding the central star, with planets just assembling themselves out of chunks of rock and ice. In fact, β Pictoris has at least one young planet already, but there’s still an awful lot of debris flying around.

And that’s what makes this discovery so important, not just as a technical tour de force, but also scientifically. “We can now begin to study a newly forming solar system in detail,” says Kiefer, “and perhaps get an understanding of how our own Solar System was born.”

It probably won’t be the last chance to do so, either. Roberge has her eye on a star called 49 Ceti, which she says is very similar to β Pic in many ways. Kiefer, meanwhile, is conducting preliminary surveys of no fewer than 30 promising stars. With powerful instruments like HARPS on the case, the word “exocomet” could become a lot more familiar before long.

Just because you've reached the edge of the solar system doesn't mean you've run out of worlds to visit. NASA's New Horizons spacecraft is set to make that point

When it blasted off for Pluto back in 2006, NASA’s New Horizons probe was poised to achieve several major milestones at once. It would be visiting the last planet still unexplored at close quarters (and yes, Pluto was still a planet when the mission began). It would also be the first mission to explore a class of planet vastly different from the Solar System’s rocky inner worlds, and also from the gas giants further out. Even after it was demoted to “dwarf planet,” Pluto represented the nearest of the ice worlds that lurk at the edges of the Sun’s influence. Understanding their true nature called for a close encounter—and New Horizons was designed to provide it.

But once the probe whips past Pluto and its moon Charon next July, it will still have functioning instruments and fuel to burn. And now, says NASA, it may have someplace to go and another scientific milestone to achieve. An intensive search with the Hubble Space Telescope has revealed three icy bodies more or less along New Horizons’ post-Pluto path and a billion miles (1.6 billion km) further out. Sometime in 2018 or 2019 the probe could be getting a close look at one of these so-called Kuiper Belt Objects (KBO)—a primordial remnant left from the very earliest days of the Solar System.

“The objects Hubble has identified are much smaller than Pluto,” says Alan Stern, a planetary scientist with the Southwest Research Institute, in Boulder, CO, and New Horizons’ Principal Investigator. “They’re the building blocks Pluto was made of.”

Hubble got this discovery in just under the wire. The rocket burn that will readjust New Horizons trajectory to intercept one of the KBO’s won’t happen until after the Pluto encounter. But in order to calculate that complicated maneuver, ground controllers need to know precisely how the KBO’s themselves are moving. “We need to make a series of observations,” says Stern, “to connect the dots.” And if they didn’t have a first set of observations by now, they wouldn’t have enough dots to connect.

In one sense, researchers have already gotten a close look at a KBO: Europe’s Rosetta probe went into orbit around a comet in August, with plans to set down a lander on its surface on November 9—and a comet is essentially a KBO that has wandered into the inner Solar System.

But that means it’s been exposed to the Sun’s heat, so unlike its cousins further out, it’s not truly primordial. Beyond that, these three new objects are between 15 and 35 miles (24 and 56 km) across. That’s about ten times bigger and a thousand times more massive than Rosetta’s comet, while still a thousand times less massive than Pluto. Whichever KBO New Horizons visits will therefore fill in a huge gap, helping scientists understand how Pluto itself formed.

It will, that is, if NASA approves the extended mission, funding the probe for longer than was originally planned. That kind of second act is not unusual—Hubble itself has had its mission extended several times, and so did the Spirit and Opportunity rovers on Mars. It’s not guaranteed, though. “We have to make a proposal,” says Stern, “but at least we now have something concrete to propose.”

Even if the mission is green-lit and that second encounter comes off, New Horizons still might not be done. “We’re going to keep looking for other KBO’s even farther out,” says Stern. If they’re close enough to New Horizons’ path, and if there’s enough fuel left for another trajectory adjustment, next July’s Pluto flyby could be just the start of an extraordinary series of close encounters with the most remote colonies in the Sun’s cosmic empire.

Sometimes the most fascinating animals are the ones that are no longer with us. The oddly named sthenurine is no exception.

Birds gotta fly, fish gotta swim, kangaroos gotta hop—unless you’re talking about the eight-foot-tall, quarter-ton, kangaroos known as sthenurines (and no, that is not a typo). These distant cousins of modern red and gray kangaroos went extinct about 30,000 years ago, and their fossils weren’t discovered until the 1800s. When the species at last came to light, it was not easy to take seriously, resembling nothing so much as cartoon versions of its modern cousins. “They were short faced,” says Brown University biologist Christine Janis, “not long-faced like modern kangaroos, and the smallest of them were as big as the largest modern kangaroos. It wasn’t clear,” she adds, “how they could hop at that size.”

And according to a new paper Janis just published in the journal PLoS ONE, they probably couldn’t. Instead, she and two co-authors conclude after several years of investigation involving more than 140 skeletons from kangaroos and related species such as wallabees, the sthenurines walked upright on two legs.

The evidence comes from virtually everywhere across the creatures’ anatomy. Their teeth, the scientists observe, look more suited to browsing on trees and bushes than nibbling on grass as modern ‘roos do. That implies the ability to stand upright on two legs to reach the branches.

“They also had flared hipbones,” says Janis, with ample room for large gluteal muscles that would have permitted them to put weight on one leg at a time, something today’s kangaroos never do. Modern kangaroos amble around on all fours—or fives, if you count the tail, which they use for balance—when they’re browsing. When they want to go fast, they hop.

That’s possible only because they have flexible backs and stiff, substantial tails, which sthenurines lacked. The sthenurine hands, moreover, were unsuitable for bearing their weight. “They would have had trouble walking on all fours,” says Janis. The animals’ very bulk would have put terrible strains on their tendons if they even tried to hop.

“Some have argued that the sthenurines might have had thicker tendons to compensate,” Janis says, “but that would have made the tendons less elastic. It just seems biomechanically unlikely.” Any arguments about tendons and other soft tissues are somewhat speculative in ancient specimens, of course. “Imagine that we only knew elephants as fossils,” says Janis. “How would we know for sure they had trunks?”

The other evidence all points in one direction, however. As Janis straightforwardly puts, “just about everything we looked at made us go, ‘oh, that fits in.'” In the often elegant study of anatomy, the answer that fits is usually the answer that’s right.

Employers often discriminate against attractive women. Here's why—and what the women themselves can do about it

It has ranked among the top ten irritating TV ads of all time. “Don’t hate me because I’m beautiful,” pouted actress and model Kelly LeBrock back in 1980, tossing her hair coquettishly as she shilled for Pantene shampoo. What few people realized at the time was that the tag line came close to describing a real type of discrimination. It wasn’t in the form of jealousy from other women, as the commercial implied; that trope has never really held up to much scrutiny. But beautiful women do face other challenges; a study published just the year before the Pantene ad ran showed that attractive women often encounter discrimination when applying for managerial jobs—with beauty somehow being equated with reduced authority or even competence. The authors called it the “beauty is beastly” effect.

What the study didn’t address, says Stefanie Johnson, assistant professor of management and entrepreneurship at the University of Colorado, Boulder, is what women are supposed to do about it. Neither did a study she herself conducted in 2010 which showed that the effect applied to a wide range of jobs normally thought of as masculine.

But a new study Johnson and two colleagues just published in the journal Organizational Behavior and Human Decision Processes does tackle the question more directly. The improbable-sounding conclusion: if you’re beautiful and female, acknowledge it. Simple as that.

Well, not quite that simple. The research doesn’t suggest attractive women say straight out, “Yes I know, I’m gorgeous.” It is, says Johnson, “a little more subtle than that.” What she and her colleagues did was to recruit 355 students, male and female, and ask them to evaluate four fictitious candidates for jobs in construction—three male and one female. The applications included photos, and the female applicant was either unusually attractive or unusually unattractive—qualities evaluated by an independent crowdsourcing group.

In some cases, the attractive woman made no reference to either her appearance or her gender in the written application. In others, she referenced her appearance, but subtly, writing something like “I know I don’t look like a typical construction worker, but if you look at my resume, you’ll see that I’ve been successful in this field.” In still others, the attractive woman referred to her gender in a similar way (“I know there aren’t many women in this industry”), but not her beauty.

The unattractive female applicants did the same (although the “I known I don’t look…” part was may have been seen as a mere reference to her gender). In general, the “employers” tended to hire attractive women more often if they alluded either to their gender and to their beauty. With the unattractive woman, referencing gender directly made no difference—but referencing appearance made them less likely than average to be hired.

The study does have holes—rather gaping ones, actually. For one thing, the construction industry is not remotely typical of the field in which gender bias usually plays out. Like it or not, there is a real reason most construction workers are men—and that’s because they are, on average, physically larger than women and have greater upper body strength as a result. It’s the reason we have women’s tennis and men’s tennis, a WNBA and an NBA and on and on. As with the less attractive candidates in the study, the attractive ones’ reference to their appearance might well have been interpreted to mean simply that the typical applicant appears—and is—male. Johnson’s findings would carry a lot more weight if her hypothetical candidates were applying for the kinds of positions in which the gender wars really do play out—vice president of marketing in a large corporation, say.

Still, as a starting point, her research has value, and she does appear to be onto something. “What we think may be going on,” Johnson says, “is that the person doing the [hiring] has an unconscious bias.” But when that bias is brought to the conscious level, triggered by the woman’s addressing it head-on (sort of, anyway), it loses force. “Once you acknowledge it,” says Johnson, “it goes away.”

The takeaway message, she argues, is not that you should feel sorry for good-looking women, since attractive people, both male and female, have all sorts of advantages overall. “It’s more that we’re exposing a more subtle form of sexism,” she says. “People are still stereotyping women.” That, all by itself, is a form of discrimination, even if in this case it’s a form few people think about.

You wouldn't ordinarily take literary advice from a neuroscientist—but Pinker's new book will make you think otherwise

Sometime during middle school, I showed my father something I’d written for a class assignment. About halfway through reading, he stopped, pointed and said “that’s grammatically incorrect. You wrote ‘I will now describe.’ The correct wording is ‘I shall describe.'” The word “will”, he told me, implies defiance and determination. But if your sentence starts with the pronouns he, she, we, you or they, the rule is reversed.

It sounded nutty, to say nothing of pointlessly precise, but that was evidently what he’d learned in grade school back in the 1930’s. As far as he was concerned, that made it an eternal truth. For decades now, I’ve just assumed that the rule had gone out of style—but on reading Steven Pinker’s charming and erudite new book The Sense of Style: The Thinking Person’s Guide to Writing in the 21st Century, I’ve learned that there never was such a rule, in the sense of something that was universally agreed on by language experts.

If anyone should know, it’s Pinker. Not only is he an extraordinarily stylish and prolific writer himself—he’s written on the history of violence, why words don’t mean what they mean, the mystery of consciousness, the role of genes in shaping character, how the mind works and more—but he’s also got the intellectual chops to back up what he says, what with his being a psycholinguist and neuroscientist at Harvard and all.

With that backing him up, it’s no surprise that while The Sense of Style is very much a practical guide to clear and compelling writing, it’s also far more. Pinker dives deep into the neuroscience of language to explain why some writing is clear, some murky and some sublime.

Style has all the fun stuff that makes usage guides so popular. For example, he lambastes the language scolds who wag their fingers over such evils as split infinitives—absurdly, Pinker says, because the rule against them is based on the fact that infinitives such as “to go” are single, unsplittable words in Latin and other languages that arose from it. Our two-word infinitives should not be governed by the old one-word rule—meaning that Captain Kirk was just fine, when he said “to boldly go.” Pinker pooh-poohs the idea that words must always stick to their original meaning: “decimate” means “to cut by ten percent” in Latin; now people use it to mean “more or less destroy,” and that’s fine with him.

Sometimes Pinker works a little too hard at this debunking campaign. He informs us that while “ain’t” is generally incorrect, it’s fine when used in expressions like as “it ain’t over till it’s over.” But since nobody has thought otherwise since the Herbert Hoover administration, it’s a point that hardly needs to be made.

Pinker then steps back from talking about excessively fussy rules to talk about something he calls “classic style”—a concept he attributes to the scholars Mark Turner and Francis-Noël Thomas. The basic rule here is “write clearly,” and Pinker’s advice on how to do so is pretty standard, albeit written with great clarity.

Among his suggestions: read your prose out loud to yourself in order to pick up on awkwardnesses that might not be evident when you’re reading silently; avoid jargon; keep your sentences short; jettison superfluous and unnecessary words—like, say, using both “superfluous” and “unnecessary” when just one will do. In one of the many tables of good versus bad that appear in the book he shows how phrases such as “for the purpose of” or “in view of the fact that” can be replaced simply by “to” or “since” with no loss of meaning.

Finally, Pinker plunges into what really sets this book apart: the neuroscientific underpinnings of what makes some writing good and some bad, based on how our brains process language. Classic style or not, this bit takes a fair amount of work to get through. Pinker acknowledges that many very good writers get by purely on intuition, but, he says:

Just below the surface of these inchoate intuitions, I believe, is a tacit awareness that the writer’s goal is to encode a web of ideas into a string of words using a tree of phrases. Aspiring wordsmiths would do well to cultivate this awareness.”

Well, maybe. But the chapter that covers these ideas is filled with sentence diagrams and technical language that runs the risk of making aspiring wordsmiths run screaming from the room. Here’s a passage in which Pinker tries to move the awareness-cultivation process along, talking about a set of words he calls “determiners.”

A determiner answers the question “Which one?” or “How Many?” Here [i.e., in a passage about a play by Sophocles] the determiner role is filled by what is traditionally called a possessive noun (though it is really a noun marked for genitive case, as I will explain).

There’s lots more of this sort of thing, which Pinker thinks “can take the fear and boredom out of grammar.” I’m not entirely sure about that. For experienced writers, however, it’s pretty fascinating stuff—the unconscious mechanics that underlie the instincts they’ve developed through experience.

In the end, Pinker’s formula for good writing is pretty basic: write clearly, try to follow the rules most of the time—but only the when they make sense. It’s neither rocket science nor brain surgery. But the wit and insight and clarity he brings to that simple formula is what makes this book such a gem.

Something strange is happening on the cloud-shrouded world known as Titan—and a NASA orbiter is trying to figure it out

It’s not the first time a formation has appeared, seemingly out of nowhere, on a world beyond Earth. Usually, it’s Mars: this year alone the Mars Reconnaissance Observer spotted a brand-new crater that wasn’t there last time NASA looked, while the Opportunity Rover discovered the amazing Ghost Rock that also didn’t exist—and then it did.

Now it’s Titan’s turn. Saturn and its moons have been under close scrutiny by the Cassini probe ever since the spacecraft arrived in the neighborhood back in 2004, discovering such oddities as geysers and a subsurface ocean on the ice moon Enceladus; a mysterious hexagon-shaped storm on Saturn itself; and a hydrocarbon cycle on Titan that mirrors Earth’s water cycle, complete with rainstorms, rivers and lakes.

But in July, 2012, Cassini spotted something that hadn’t been there anytime in the previous seven years: a bright spot, covering about 30 square miles (78 sq. km), in the lake known as Ligeia Mare, which is bigger than Lake Superior. NASA called it a “transient feature,” while the Internet dubbed it the “Magic Island.” And as of August 21 of this year, the space agency has just announced, it was still visible—and in fact, it had doubled in size.

“The fact that it’s still there shows that it isn’t just some artifact of the imaging system,” says Jason Hofgartner, the Cornell grad student who’s in charge of figuring out what the darned thing is. “Something is really happening on Titan.”

Hofgartner and his colleagues have narrowed the “something” down to four possibilities. “It could be waves,” he says. “It could be bubbles rising up from the bottom. It could be solids of some kind floating on the surface—or solids suspended below the surface. All of these,” he says, “are equally viable at this point.”

The scientists are convinced, however, that the mystery island almost certainly has to do with the changing of seasons on Titan. Riding along in its orbit around Saturn, Titan takes 30 years to circle the Sun, and the northern hemisphere, where Ligeia Mare is located, is just at the start of its 7 1/2-year summer. It’s bathed in solar energy, and, says Hofgartner, “any of those [features] could be powered by the seasonal change.”

If so, it wouldn’t be the first time scientists have seen seasonal effects on Titan: when Cassini first arrived in the Saturnian system, the moon’s southern hemisphere was edging into the end of summer, and observations suggested at the time that evaporation had shrunk the lakes in the region from their maximum extent—the same thing that happens to lakes and reservoirs on Earth.

In fact, the search for evidence of seasonal changes on Titan was a primary objective of the Cassini mission, and the space probe should get at least another look at the mystery island before the mission ends.

That won’t remotely solve all of the mysteries about this extraordinary moon, however. It’s nothing less than a Bizarro version of Earth, with methane and other hydrocarbons taking the place of water. “It has all kinds of processes we can learn about,” says Hofgartner, “which could help us understand processes on Earth better.”

That could call for a return visit one day by a successor of Cassini. “There are lots of reasons,” Hofgartner says, “to go back.”

There's a reason you get sleepy at night: because it's dark out. Now a little blind fish helps explain all that

Birds have ‘em. Bees have ‘em. Even bacteria have circadian rhythms, the ramping up and slowing down of internal functions that signals organisms to be more or less active, depending on the time of day. Humans have circadian rhythms too—and when they’re disrupted by time-zone changes, lack of sleep or working the night shift, the result can be an increased risk of heart attacks, depression, diabetes, weight gain and more.

For eyeless Mexican cave fish, however, no problem, says a new study in the journal PLOS ONE reports. “Some organisms have stronger circadian rhythms, and some weaker,” says lead author Damian Moran, of the private company Plant and Food Research, based in New Zealand. “But these fish have none at all.”

The finding, says Moran, “just fell into our laps.” He and his colleagues were actually studying the energy costs of vision—that is, how much of the body’s resources evolution thinks it’s worth devoting to having the advantage of being able to see. The Mexican tetra fish is especially useful for such studies because it comes in both a surface-dwelling subspecies and several versions that live in caves, in perpetual darkness (the latter, says Moran, “look a little like Gollum“).

In order to measure the energy cost of having vision, the scientists put both versions of tetra into a kind of fish treadmill, where they could swim constantly upstream while instruments measured their oxygen intake, a gauge of their energy use. To cover all their bases, the scientists tested both types of fish under their most familiar conditions—with a day-night cycle, and in total darkness.

The scientists were looking to measure the differences in energy use between the fish with eyes and those without—but they noticed something else as well. “The surface-dwellers,” says Moran, “had a typical increase of oxygen use during the day, and a decrease during the night. Whereas the cave fish showed a flat line day and night.”

It makes sense: an animal that lives in changing conditions of light and darkness needs to be more active when its food sources are more active, whereas a creature that never sees the light of day probably doesn’t care. Even so, since many organisms that live in utter darkness are descended from surface-dwellers, they maintain at least a weak circadian rhythm. But the cave-dwelling tetra have none, and because they don’t have to ramp their metabolism up and down, they use 27% less energy overall than their daytime-nighttime cousins.

While this is the first such animal ever found, says Moran, the eyeless tetra might actually be just the tip of a gigantic biological iceberg. “Most of the Earth’s biomass lives in areas that never see light at all. I suspect that when we look in the deepest part of the sea or deep underground,” he continues, “we’ll find many organisms that have no circadian rhythms.”

Because after all, what’s the point?

A populist uprising restores a space favorite to the planetary ranks. Will the astronomers listen?

When Pluto was hurled from the pantheon of planets back in 2006, it could simply have slinked away, accepting its new title of “dwarf planet” without a fuss. But thanks to the undying support of its millions of fans—not just schoolchildren, but many astronomers as well—the little planet that could is still a contender.

The latest evidence: a debate at the Harvard-Smithsonian Center for Astrophysics, in which three astronomers squared off to present both sides of the question: “Is Pluto a Planet?” And when the dust settled, the audience, made up mostly of ordinary citizens, declared once again that the answer is “duh, obviously.”

Three may seem like one side too many, but David Aguilar, the Center’s director of public affairs, who set up the debate, wanted to look at the question not just from a scientific perspective, but also through the lens of history. The first speaker, therefore, was the eminent Harvard astronomer and historian of science Owen Gingerich. “Planet,” he pointed out, “is a culturally defined word that has changed its meaning over the ages.”

In fact, the word itself comes from an ancient Greek word meaning “wanderer.” Unlike the stars, which seem fixed in place, the planets are objects that wander from one constellation to another in the sky—and since the Sun and the Moon do that too, they were originally considered planets as well.

That designation didn’t last, of course, but when astronomers began finding asteroids in the early 1800’s, they were also counted as planets, at least as first, (The fact that astronomer William Herschel had recently discovered the new planet Uranus had evidently given the scientists’ a taste for more.) Within a few decades, though, astronomers found so many asteroids that things were getting confusing. Objects like Ceres and Vesta, the largest asteroids in the asteroid belt, were demoted from “planet” to “minor planet,” in a foreshadowing of Pluto’s fate a century and a half later—and it had nothing to do with any sort of scientific definition of the word.

And neither did the International Astronomical Union’s decision to downgrade Pluto in 2006. Just as with the asteroids, astronomers began finding additional Pluto-like objects starting in the 1990s, including Eris, which turns out to be essentially the same size as Pluto. If Pluto is a planet, so is Eris, and so are several other objects at the edge of the Solar System.

That would be just too confusing, argued the second debater, astronomer Gareth Williams, associate director of the IAU’s Minor Planet Center. If you let Pluto stay, he said, you logically have to let the number of planets rise to 24 or 25, “with the possibility of 50 or 100 within the next decade” as more objects are found. “Do we want schoolchildren to have to remember so many? No, we want to keep the numbers low.”

This isn’t exactly a rigorous scientific argument—so to give its decision the flavor of science, the IAU came up with a definition of “planet” so convoluted it seemed entirely arbitrary. To qualify as a planet, a body must orbit the sun and be large enough to be at least roughly spherical—two rules that make sense. But it must also have gravitationally “cleared its neighborhood” of other bodies, meaning it has its orbital traffic lane all to itself, which Pluto doesn’t—at least during the most remote portion of its journey around the sun. The rule seemed carefully crafted so that “dwarf planets” like Pluto, Eres and the asteroid Ceres didn’t make the cut.

“It didn’t make sense at all,” said Center for Astrophysics communications director David Aguilar, who set up the debate. “Isn’t a dwarf fruit tree also a fruit tree? Isn’t a dwarf rabbit a rabbit?” But in the end, the resolution was approved by IAU members, and in 2006 the number of planets was pared from 9 to 8—the ones known to science pre-Pluto.

The last debater was astronomer Dimitar Sasselov, director of Harvard’s Planets and Life initiative. His argument, he explained in a conversation after the debate, was that the word “planet” does need a scientific definition, but that we don’t know enough yet to create one. The reason: we’ve discovered thousands of planets orbiting stars beyond the Sun, and until we can understand how they formed and what they’re really like, any definition is premature. Pluto may be a planet based on scientific reasoning, or it may not be. “For now,” he said, “we should keep Pluto as a planet by default.”

In the end, the Harvard audience voted in favor of Pluto’s reinstatement by a landslide. Planetary scientist Alan Stern, whose new New Horizons probe will reach Pluto next summer for a first-ever close encounter, wasn’t there. But when he heard about the vote, he said, “every time there’s a poll it turns out this way. The IAU have become largely irrelevant in this.”

The organization may seem to count even less when you consider something Gingerich revealed during his arguments. He was there for the 2006 IAU vote, which came when most of the attendees had already gone home. Just 424 of the organization’s nearly 10,000 members were present, and when the organizers offered the gathering the chance to reconsider Pluto’s demotion, Gingerich said, “they voted not to vote again because they wanted to go to lunch, so that was the end of it.”