TIME Design

WATCH: The Science Behind the World’s Biggest Wooden Roller Coaster

Whether you can't get enough of them or can't go near them, roller coasters rely on some pretty nifty tricks of physics and design.


Your brain wants nothing to do with roller coasters—and for a wonderfully simple reason: your brain would very much like you to stay alive. So anything that’s designed to haul you up to the top of a very steep incline, drop you straight down, very fast, and repeat that process over and over again for a minute or two is something that elicits a simple, highly adaptive response in you—which pretty much involves running away.

That, at least, is how it’s supposed to work, but your entire brain isn’t in on the game. There are also thrill-seeking parts, adventurous parts, parts that like the adrenaline and serotonin and endorphin kicks that come from roller coasters. So while millions of people avoid the things, at least as many millions swarm to them, looking for ever bigger, scarier rides and ever bigger, better thrills. This summer they’ll get their wish, thanks to the opening of the appropriately named Goliath roller coaster, the biggest and fastest wooden coaster ever built, which just took its inaugural runs at the Six Flags Great America amusement park in Gurnee, Ill., about 50 miles north of Chicago.

Goliath is destined to be a tourist magnet, a cultural icon—at least until another, even bigger one comes along—and a lot of fun for a lot of people. But it’s also a feat of engineering and basic physics. And if you’re the kind of person who enjoys that sort of thing while hating the idea of actually ever riding on roller coasters—the kind of person I’ll describe as “me,” for example—there’s a lot to like about Goliath.

Modern roller coasters typically come in two varieties, wooden ones and steel ones—known unimaginatively if unavoidably as “woodies” and “steelies”—and coaster lovers debate their merits the way fans of the National and American Leagues debate the designated hitter rule.

Steelie partisans like the corkscrews and loop-the-loops made possible by the coasters’ bent-pipe architecture. Woodie fans prefer the old school clack-clack and the aesthetics of the entire structure. What’s more, plunging into and soaring through all the wooden bracing and strutwork necessary to keep the thing standing increases the sensation of speed because stationary objects that are close to you when you’re moving at high speed seem to whiz past so fast they blur. Steelies leave you more or less moving through open space, and that eliminates the illusion.

Goliath moves at a top speed of 72 mph, achieving that prodigious feat with the aid of a very simple fuel: gravity. As in all roller coasters, its biggest, steepest drop is the first one, because that’s the only way to generate enough energy to propel you through the rest of the ride—which is made up of steadily shallower hills. In the case of Goliath, that first hill is 180′ tall (55m), or about the equivalent of an 18-story building. The drop is an almost-vertical 85 degrees.

As test pilots and astronauts could tell you, such rising, falling, corkscrewing movement creates all manner of g-force effects. Most of the time we live in a familiar one-g environment. Climb to 2 g’s in a moving vehicle of some kind and you feel a force equivalent to twice your body weight. The maximum g’s Goliath achieves is 3.5. Get on the ride weighing 150 lbs., and for at least a few seconds, you’ll experience what it’s like to weigh 525 lbs.

But g forces can go in the other direction, too. With many roller coasters, the forces bottom out at about 0.2 g’s during downward plunges, meaning your 150 lb. one-g weight plummets to 30 lbs. That can give you a feeling of near-weightlessness. It’s also possible to achieve 0 g in a dive, which is how NASA’s famed “vomit comet” aircraft allow astronauts to practice weightlessness. On the Goliath, things go even further, with riders experiencing a force of minus 1 g.

“That means you’d be coming out of your seat,” says Jake Kilcup, a roller coaster designer and the chief operating officer of Rocky Mountain Construction, which designed and built Goliath. To ensure that that doesn’t happen, the Goliath cars are equipped with both lap bars and seat belts.

Though Goliath is made of wood, it does feature two so-called inversions—or half loops that take you to the top of a climb, then deliberately stall and plunge back down the same way. One includes a “raven turn,” or a twist in the track that turns the cars briefly upside down.

Even this much wouldn’t be possible on a wooden coaster if not for what Rocky Mountain calls its “Topper” track technology—a sort of hybrid of wood and metal. Most of the beams in the Goliath superstructure are made of nine laminated layers of southern yellow pine, steam-bent in stretches that call for curves and then kiln-dried. But the track itself also includes hollow metal rails running the entire 3,100 feet (or nearly a full kilometer) of the ride. The cars all have main wheels that sit on the rails as well smaller upstop and guide wheels that lock the cars to the tracks and keep them going where they’re supposed to.

“The Topper track gives a smoother ride than you get on an all-metal track,” says Kilcip, “and makes the overall roller coaster stronger than an all-wooden one.”

All that technology provides a relatively brief ride—just 87 seconds long, which is not atypical for roller coasters. For plenty of people, that’s way too short—which is what Six Flags is banking on to keep the turnstiles spinning. For plenty of other people, it’s precisely 87 seconds too long. And you know what? I’m not—um, I mean, those people aren’t—the slightest bit ashamed to admit that.

TIME Soccer

Stephen Hawking Calculates England’s Chances of World Cup Success

Science predicts the chances of a first win in almost 50 years


Renowned physicist and cosmologist Stephen Hawking has nailed his colors firmly to the mast ahead of this summer’s World Cup in Brazil.

Applying his scientific mind to the random-number generator that is Association Football, Hawking has pulled data from previous World Cup performances to determine how England can lift its first trophy in almost 50 years. Unfortunately for England fans, however, not many of Hawking’s criteria look likely to be met this summer.

Among other things, he notes that England plays best at lower altitudes (two of its first three matches take place at altitudes close to the highest point in England) and with kick-offs at 3 p.m. (all its group matches start in the evening).

Referring to England’s chances in a penalty shoot out, Hawking added “As we say in science, England couldn’t hit a cow’s arse with a banjo.”

TIME Television

The Physics of the Game of Thrones “Moon Door”

Game of Thrones: Lysa, Littlefinger
Mind the gap! Helen Sloan / HBO

Would a person really break into pieces after being dropped from the Moon Door?

Spoilers for the Game of Thrones episode “Mockingbird” (Season 4, Episode 7) follow

When Game of Thrones fans first met the Moon Door, it was described as an “elegant” solution to the problem of administering justice. When Tyrion Lannister arrived in the Vale and was made to stand trial for his non-crimes, Lysa Arryn explained that those found guilty in her mountainous realm were disposed of via gravity, not swords or ropes. The Moon Door, a hole leading to uncounted feet of air and then the rocky ground below, is the preferred method of execution. (In the books, it’s a standing door with a crescent moon carved into it, but the nothingness is probably more visually effective when the camera is looking down rather than out.)

As Lysa would later explain to Sansa in the episode “Mockingbird,” which aired May 18, people who leave through the Moon Door break apart on the rocks below. Sometimes an intact body part will be found, but the person essentially snaps.

Of course, it was Lysa, not Tyrion or Sansa, who would eventually get to experience that wild ride first hand.

But would Lysa’s death really go down — no pun intended — the way she thinks it would?

Not necessarily, according to Jim Hamilton, who runs the Free Fall Research Page, a compendium of information about falls from great heights. Though we don’t know the exact height of the Moon Door, he says that if it’s more than 2,000 feet up, the faller would reach 125 miles per hour, which means broken bones and near-certain death — but not necessarily breaking into pieces.

“I’ve never actually been asked that question,” Hamilton tells TIME, in response to the query of whether someone in Lysa’s situation would snap apart like a twig. “It would depend on the surface you hit. Maybe if you hit a rocky beach. People who fall into meadows or marshes or sand leave a human-shaped impression on the ground. They almost tend to bounce sometimes. I would think that would be more likely than breaking apart.”

And what about the Moon Door’s “elegance” as an executioner? It turns out that, as unlikely as it sounds, such a fall wouldn’t be a 100% guarantee of death. Hamilton cites the fact that during World War II, for example, there were lots of people falling out of burning airplanes — and, though many of them died, a lucky few survived, often thanks to a combination of factors that slowed their falls. Hamilton’s website chronicles the stories of several such people who survived falls from great heights.

Still, don’t look for a twist wherein Lysa comes limping back. Despite stories of long-odds living, Hamilton says she’s probably done for — even if she’s still in one piece.

TIME Physics

The Mystery of Dark Matter: WIMPS May Have the Answer

At the heart of our galaxy, the WIMPS are at war
At the heart of our galaxy, the WIMPS are at war Pete Saloutos; Getty Images/Image Source

Eighty percent of the universe is utterly invisible, but an exotic dance of mutually annihilating particles may explain it all

It’s a mystery that has haunted astronomers for nearly 80 years now: what is the mysterious dark matter that outweighs ordinary matter—all of the atoms that make up stars, galaxies and clouds in the cosmos—by a factor of four to one? We know with near-certainty that it’s out there because of its powerful gravity. Galaxies spin so fast that they’d fly apart without the massive cocoon of dark matter that surrounds them, pervades them and holds them together.

It’s not that theorists are at a loss for what the dark matter might be: the smart money says it’s a still-undiscovered type of elementary particle, produced in gigantic quantities in the immediate aftermath of the Big Bang. So far, however, despite decades of trying, nobody has managed to find anything more than a circumstantial case to back up this notion.

But that may be changing. A team of astrophysicists from a half-dozen top-tier universities and labs say they have evidence from the orbiting Fermi Large Area Telescope that some of the gamma rays emanating from the core of the Milky Way could be produced by dark matter particles colliding with and annihilating one another. The authors acknowledge that plenty of astrophysical processes generate gamma rays, but when you add up all of those known sources, says co-author Dan Hooper, of the Fermi National Accelerator Laboratory, near Chicago, “there’s a significant excess we can’t explain.” And while that’s far from a smoking gun, dark-matter particles are at the very least a plausible explanation.

Here’s the reasoning: based on their understanding of the Big Bang and what came out of it, physicists are convinced dark matter can’t be made of ordinary quarks, electrons and other standard particles. It has to be something else, and what fits the bill best is a type of particle that responds to only two of the four basic forces of nature—gravity and the weak nuclear force, to be specific. (The other two are the strong force and electromagnetism.)

These bits of exotic stuff, known generically as weakly interacting massive particles (or WIMPs, and yes, it’s deliberately cute), could come in matter and antimatter versions, like many particles do. Or they could be their own antiparticles, which is permitted by the laws of physics. Either way, if they approached each other closely (as they would in the densely packed heart of the Milky Way), they would annihilate each other, sending out, among other things, a burst of gamma rays that the Fermi telescope could detect.

Not only have gamma rays been spotted, the precise levels the Fermi telescope has detected are just what you’d expect if some of that radiation really is produced by WIMPS engaging in mutual destruction. But that’s where things start to get tricky. Astrophysicists think they know how many gamma rays should be coming from other sources—ordinary particles slamming into other particles, or bursts of energy from the ultra dense stellar corpses known as pulsars—but they’re not certain.

“We believe we understand these things,” says Harvard astrophysicist Doug Finkbeiner, another author, “but there’s always room to make a mistake.” So the new signals could be the result of dark matter, he says, or they could be caused by pulsars making more gamma rays than astronomers think. “Dark-matter people want it to be dark matter,” says Finkbeiner, “but pulsar people want it to be pulsars. And it could also be none of the above, something we haven’t thought of yet.”

Hooper agrees, but he puts a bit more of a positive spin on it. “We’re claiming the detection of anomalous gamma rays, and no more,” he says. “But I haven’t seen any explanations other than dark matter that hold water at this point. This is the first time I’m willing to move from ‘it looks like it might be the signal of dark matter’ to ‘it looks like it is the signal of dark matter,’ and that’s qualitatively different.”

The final verdict won’t be in for some time, though. One way the mystery might be resolved is simply through longer and more thorough observations with the Fermi telescope. “We have only four years’ worth of data,” says Hooper, “but with more time we should have a better sense of what we’re seeing.”

Another way might be via the Large Hadron Collider, which made headlines in 2012 when it found the Higgs Boson, and which has now turned its attention to finding WIMPS, among other things. The nature of dark matter could also be confirmed by one of the underground particle detectors hoping to snag a passing WIMP as it zips through the Earth. Or, it might come from an instrument called the Alpha Magnetic Spectrometer, riding aboard the International Space Station. One way or another, however—unless astrophysicists have been pursuing a total dead end for the past couple of decades, that is—a mystery that has dogged science since Franklin Roosevelt occupied the White House may finally be on the verge of a solution.

TIME The Universe

You Should Care Big Time About the Big Bang News

Big Bang News: Why You Should Care
In the instant after the Big Bang, the universe expanded faster than the speed of light Getty Images

Science doesn't have to be practical—or even entirely fathomable—to be breathtaking

Exactly why do you have to give a hoot about Monday’s landmark announcement that, in a single observation, physicists have given a big boost to the Big Bang? You don’t, actually. It will not change a single thing about your life, the life of anyone you care about or the state of the world. So in some respects, we’re done here.

But in other respects there’s a lot to love.

Science has, in some ways, always been measured by its payoff. Polio vaccine? Hundreds of thousands of children per year spared paralysis or death. Eradication of smallpox? Hundreds of millions of lives saved over the arc of time. The invention of the telegraph, the telephone, the airplane, the personal computer? World-changers.

But what about the invention of the telescope? It landed Galileo—he of the heliocentric heresy—in a world of hurt, as well it would have by the thinking of the time. Yes, he found the moons of Jupiter and rings of Saturn, but by showing other worlds in all their non-Earthly complexity, he also blew up the notion of cosmic specialness that had been at the center of our species’ overweening ego for so long. Later generations of telescopes gave us more information we could make no practical use of and that only served to shrink us further, revealing that we are crazily small organisms on a crazily small world and that, on a cosmic scale, our species’ entire time on the stage amounts to little more than the trillionths of a second it took the Higgs Boson to flash out of existence after its celebrated creation in 2012.

And what about that Boson? A couple of years ago we were all aflutter about it, so quick, what did we learn from it? Um, something about mass and particles and energy and blah, blah, blah Einstein (half of these discoveries end up with blah, blah Einstein).

But there was something about the boson that got to us, too. Even if you didn’t pay much attention, you knew that it involved a huge machine creating an unfathomably tiny particle, one that somehow reached all the way back to the Big Bang and helped explain something deeply fundamental. That something had to do with why there is matter in the universe at all. But even if you never got that far, you sensed—just sensed—that this was something that made us, the whole species, better, smarter, just faintly immortal, if only by having transcended our multiple limitations to figure out something very hard.

And so it is with Monday’s announcement, that gravitational waves which, yes, Einstein again, first posited 99 years ago, actually exist—and that they send ripples out across all of spacetime. That, in turn, confirmed that in the first billionth of a trillionth of a quadrillionth of a second after the Big Bang, the universe briefly expanded faster than the speed of light—a speed that’s supposed to be impossible, but in this exceptional case wasn’t. And while it would be nice to understand even more, even that little bit has to leave you feeling gobsmacked.

It’s that way with all thrilling things that make no sense: scaling Mount Everest, breaking the four-minute mile, landing the first man on the moon. Hell, back in 1962, we fiercely defended the greatness of the failed Ranger 4 mission after it crash-landed on the lunar surface but was unable to take even a single picture. Why? Because we had finally put metal on the moon—dead metal to be sure—but we had gotten there and that was enough for the moment.

It’s fine—and vital—to do science that changes lives. But it’s great to also do science that just gets you drunk on the idea that you’re doing it at all, that refracts the universe in a different way, that shows you yourself from the other side of the mirror. You are precisely the same person you were before you had that perspective—and you’re entirely different too.

TIME Cosmology

Cosmic Bulletins: Two Major Discoveries Rock Science

Telescope BICEP2 (in the foreground) and the South Pole Telescope (in the background) in Antarctica, on March 31, 2007.
Telescope BICEP2 (in the foreground) and the South Pole Telescope (in the background) in Antarctica, on March 31, 2007. Steffen Richter—Harvard University/EPA

Nearly a century ago, Einstein came up with the idea of gravitational waves. Now, in a discovery that physicists are calling "extraordinary" and "spectacular," observers at the South Pole have found the first direct evidence they exist

The Theory of General Relativity seemed truly bizarre when Albert Einstein first articulated it 99 years ago: gravity, the great physicist declared, was no longer to be seen as a force, but rather as the warping of “spacetime,” an amalgam of those two formerly independent concepts. The theory also predicted that violent events should trigger gravitational waves, which would set spacetime rippling, like a vat of cosmic jello. There has been some circumstantial evidence of those ripples, involving changes in orbits of binary stars, but what’s always been missing is a smoking gun, direct observational measurement of a gravitational wave.

The same is true of the Inflationary Universe theory, postulated in the 1980s: just .0000000000000000000000000000000000001 seconds (give or take) after the Big Bang, the theory said, the cosmos underwent a burst of expansion so furious that it was briefly flying apart faster than the speed of light. Exceeding light speed is supposed to be impossible, except that that law applies only to something moving through spacetime, not spacetime itself expanding. Just as with gravitational waves, there’s plenty of reason to think it really happened, but again, no proof.

Not until now, anyway. In a discovery physicists are calling “huge,” “extraordinary” and “spectacular,” a team of observers using a microwave-sensitive telescope at the South Pole has found the first direct evidence of gravitational waves—and the strongest proof of inflation to date, all in one shot. “When I got the call,” says Marc Kamionkowski, a theorist at Johns Hopkins University who wasn’t involved in the research, “I had to ask if it was real. To me, this is bigger than the Higgs boson.” If it’s confirmed by other groups, says Avi Loeb, chair of the Harvard astronomy department and also not a participant in the research, “it’s worth a Nobel.”

According to Kamionkowski, one of few physicists allowed to see the scientific paper before it was announced at a press conference today, that confirmation is likelier than not. “These are extremely careful and conservative people,” he says of the team that made the observation. “They’ve had this evidence for three years, looked at every alternative explanation for what they were seeing, and systematically ruled them out one by one.”

For a finding of this enormity, the critical bit of evidence John Kovac of the Harvard-Smithsonian Center for Astrophysics and his colleagues saw seems entirely innocuous: a slight distortion in microwave radiation left over from the Big Bang. These microwaves didn’t even exist until about 400,000 years after the Big Bang happened, far later than the inflationary scenario—which occurred before the universe had aged even a billionth of a trillionth of a quadrillionth of a second—could have played out. But when the microwaves did pop into existence, the cosmos should have still been jiggling with gravitational waves set off by the violence of the inflation. Spot the jiggles and you prove both the expansionary phenomenon and the existence of the waves left over from it.

That’s what Kovac and his colleagues did, though it wasn’t literally jiggles that they saw. Instead they noticed that the background radiation was polarized, its waves of electromagnetic energy oscillating not in random directions but in just a few specific ones. (Sunlight also oscillates in random directions; polarizing sunglasses work by letting in only the rays within a narrow range of orientations.) That microwave polarization suggests that something was shaking the radiation this way or that.

The telescope the researchers used—the Background Imaging of Cosmic Extragalactic Polarization 2, or BICEP2, instrument—is tuned to see the critical kind of polarization in background radiation, but there was no guarantee it ever would. Inflation theory comes in several versions, all of which posit different intensities. “In some,” says MIT’s Alan Guth, who was one of the inflationary universe theory’s original inventors, “the waves are so weak they could never be detected. To see them turn up is beautiful.”

What made the gravitational waves—and thus the polarization they caused—so powerful has to do with why the universe inflated in the first place. Physicists like Guth had already theorized that inflation would happen as the cosmos transitioned from one energy state to another, much as water changes to ice. That transition released huge amounts of energy, which turbocharged the already-expanding universe. Also like water, which goes from vapor to liquid to solid, the post-Big Bang universe went through several such transitions, all during the first fraction of a fraction of a second of its life.

The amount of polarization—dictated by the strength of the gravitational waves—suggest that the transition that triggered the high-speed inflation occurred when the universe was at the so-called grand unified scale. That’s the point at which electromagnetism, the weak nuclear force and the strong nuclear force, all of which have vastly different strengths and effects today, were a single force. “It represents about a trillion times the energy scale produced by the Large Hadron Collider,” says Loeb, referring to the world’s biggest accelerator, where the Higgs was found.

The new results, assuming they’re verified, now rule out some of the more complicated, exotic versions of inflation, which seemed favored by cruder measurements made last year by the European Planck satellite. “Some people liked those,” says Guth, “because they got to write complicated papers about them.” But in physics, simpler ideas are usually considered more elegant.

Also ruled out by the detection of gravitational waves, according to both Guth and Loeb, is at least one of the few viable alternatives to the Big Bang. Known as the ekpyrotic universe model, it posits that the cosmic microwaves we’ve been detecting since the 60’s came from the titanic collision between two “branes”—short for membranes—which were independent universes (one of which was ours) floating around in higher-dimensional space.

The new results do have to be verified. Even though the BICEP2 team methodically checked and rechecked its work to rule out any mistakes, nobody, including Kovac and his colleagues, can be 100 percent certain until independent groups, using their own instruments, see the polarization signal too. That shouldn’t take long, given that cosmologists at Princeton, Berkeley, the University of Minnesota, the Goddard Spaceflight Center, the University of Chicago and more were already in the hunt. “Whether it’s correct or incorrect“ says Kamionkowski, who strongly favors the former, “will be known very quickly.”

Meanwhile, the BICEP2 team has already started taking data with a more powerful telescope called the Keck Array, also at the South Pole, and is hard at work building yet another, called BICEP3, which will begin flexing its muscles next summer. Extraordinary as the new results are, they’re just a taste of the science that will come out of these new instruments. “I’ve made 23 trips to the Pole in my career so far,” says Kovac, “and I’ll be making a lot more.” It’s a long, cold journey—but to understand the first moments of cosmic creation, it’s clearly worth it.

More: The Sights And Sounds Of The Solar System From NASA’s Deep Space Network

TIME review

Famous Scientist Will Make You Smart. Click Here

Bestselling author and Ivy League physicist Brian Greene is launching an online university like none before it

Brian Greene is the best college professor you never had—unless you’ve studied physics at Columbia University, that is. If that does describe you, and you have sat in a Greene-taught class, you’re not likely to have forgotten the experience.

For the far, far larger number of people who are not part of that rarefied group, it will soon be possible to study with Greene anyway. On March 6, his online classroom series—ambitiously titled the World Science U (WSU)—goes live. And if the name seems like something of a reach, early samples of the course material suggest that he may indeed have the stuff to deliver what he promises.

The traditional model for the college course—instructor in the front, students in the seats, while lecture is presented and notes are taken—is a little like the famous description of democracy as a form of government: it’s the worst system imaginable, except for all of the others that have ever been tried. Independent study will never have the accountability a supervised class does. Correspondence courses never had the exchange of ideas that a classroom offers. The answer, in recent years, was supposed to be MOOCs—massive open online courses.

(MORE: Nine Ways Quantum Computing Will Change Everything)

As the name suggests, the web-based MOOC is open to anyone—though fees, if they are charged at all, may be waived for students of the university sponsoring the courses. The “massive” part is not an exaggeration; the number of people who can log onto a course is limited only by the bandwidth of the server, and with any tests that are given scored by computer, the whole world can be the lecture hall.

But MOOCs have problems, not the least being student followthrough. A recent study conducted by the University of Pennsylvania and sponsored by the Gates Foundation looked at 1 million MOOC students across dozens of courses and found enormous attrition rates, with, for example, 140,000 quizzes taken and submitted after the first lecture in one surveyed course, and only 20,000 after the last lecture. A survey of 16 different courses found online attendance rates as low as 2% by the end of the curriculum.

Those numbers, however, aren’t quite as bleak as they seem, as an analysis published in The Atlantic in January showed. A significant share of people who enroll in MOOCs have no intention of sticking with them to the end. Often they’re people who know much of the material already and are simply dipping in for a refresher; alternatively, they might be new to the topic and are sampling, say, what a geology course is like before deciding if they want to make it their field of study.

(MORE: The Physics of Curly Hair—Because You Deserve to Know)

But that wasn’t the case made for MOOCs by those who believe they can change the nature of education, and no one pretends that there’s any way to spin single-digit completion numbers as an unalloyed good thing. Enter Greene and his WSU.

Known widely for his best-selling books, including The Elegant Universe and Icarus at the Edge of Time, as well as the related PBS specials, Greene is also the founder of the World Science Festival, held each year in New York City. He propelled himself from the classroom to the bookstores to PBS gold mostly through the energy he projects as he teaches and the imagery he sprinkles through his course material. His specialty is string theory and theoretical physics, topics that can turn to lead in the wrong hands but come to life in the right ones—and Greene manages them artfully.

He has divided his free-of-charge WSU curriculum into three levels: quick, 30- to 90-second videos that explain a single narrow concept in physics (he has recorded a remarkable 500 of these); two- to three-week courses that involve no homework and—to the delight of more people than would admit it—no math; and longer, in-depth, college-level courses, stuffed with all of the equations it takes to master the material in a truly academic way. He also includes what he calls “Office Hours,” giving real students the opportunity to ask the virtual Greene any questions that come up in the course of a lecture. After 18 years of teaching, he knows what the most frequently asked of those questions are likely to be.

(MORE: Hawking: Is He All He’s Cracked Up to Be?)

The lectures, which were recorded over weeks and months in a brick-walled studio that has the appealingly casual look of the early MSNBC or the current CNN morning program, go heavy on the graphics, animation and touch-screen technology. Watching the videos (and, full disclosure, TIME has sampled only a handful of them, and none of them involved equations, thank you very much) has the odd effect of making physics seem like a guilty pleasure—something that, surely, one of the most head-crackingly difficult of the sciences has rarely been called. But if you like this stuff—and a lot of people do, or books like Greene’s and Stephen Hawking’s wouldn’t sell the way they do—there is a compulsive watchability to what Greene has done.

It’s impossible to know if the WSU is a viable model for future MOOCs to follow. Until the site actually launches and has a year or two to run, there will be no data available on how long students actually stick with the courses, and it will be harder still to determine how much they actually learn and retain. Greene reports that his Columbia students who use the WSU videos as a sort of textbook for his classroom course score higher on tests than other students do, but that’s a small sample group in a decidedly non-double blind study. What’s more, not every university—to say nothing of every department in every university—has a communicator like Greene teaching its material, anymore than they all have a Neil DeGrasse Tyson, or the Carl Sagan who came before them both.

But that’s nothing new. The gifted science communicator has always been harder to come by than the science. Greene, undeniably, is one of that rare breed. In his new venture, he makes that fact lyrically evident.

(FROM THE MAGAZINE: The Infinity Machine)

TIME Physics

The Physics of Curly Hair—Because You Deserve to Know

Still life of 3 different hair colors. close up.
Getty Images

Want to know why your 'do often don't? Science has an answer for you

Correction appended, February 14

If you like (or don’t like) your curly hair, you can thank (or blame), your genes, your shampoo, your climate and your hairdresser. But the fact is they’re all bit players. The real determinant of whether your hair does what you want it to do at any one moment is physics. And a new paper in the journal Physical Review Letters—which is not typically in the habit of offering haircare tips—explains why.

Physicists have never had very good computer models to represent how a curled strand of a flexible material behaves, which is one of the reasons the characters in computer animated cartoons tend to have straight hair. (Kudos to Pixar for giving it a go in Brave). But there’s more than cartoonery at stake in this particular curling event; industrial manufacturers are affected too. “We think of steel pipes as being nice and straight but usually at some point they’re getting wrapped around something,” said MIT graduate student James Miller, who participated in the study, in a statement accompanying its release. “And at large dimensions, they’re so flexible that it’s like . . . dealing with a limp spaghetti noodle.”

To try to understand that, the investigators came at the problem in a number of ways—experimenting with flexible rubber tubes of different widths and lengths, modeling what they learned in a computer, and throwing in a dash of theory. It’s a combination MIT engineer Pedro Reis, one of the study’s authors, called “the perfect triangle of science.” (Reis, for what it’s worth, takes pleasure in pointing out that he’s bald, which perhaps makes his work especially credible since he has no skin—or, rather, only skin—in the game.)

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The investigators concluded that the biggest variable curly hair has to reckon with is weight. The longer a hair grows, the more of a burden the bottom of the shaft must carry until the strand as a whole topples over. Straight hair lays flat after that, becoming what the investigators call a 2-D hook, since it effectively moves in just two dimensions, front to back or side to side. A hair with an innate curliness to it is only beginning its adventure in multi-directional physics. If your curly hair is relatively short, each strand forms what the researchers call a 3-D local helix—growing up, down, swooping in at angles, doubling back on itself. If the hair extends the length of the head or beyond (Brave, we’re looking at you again), it’s called a 3-D global helix, and its behavior, accordingly, becomes more complex.

OK, none of that—save the fancy physics talk—is especially new. You don’t need terms like local helix and global helix to know that short hair is, um, short, and long is long, and they tangle up in different ways. But a curly hair shaft is defined by more than its shape. It also has its own thickness, stiffness and weight, which is particular to the person. The actual number of hairs per square inch on any individual’s scalp can differ from that of another person too, and that greater or lesser crowding may also play a role

All together, it’s exactly the kind of complex, chaotic system that physicists consider a good challenge and everybody else considers a bad hair day. But when Reis and his colleagues reduced all of those variables to algorithms and fed them into their models, they found that they were able to predict the behavior of any type of strand, from fine hairs to thick hairs to massive industrial pipes, and to change their properties by tweaking those variables.

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“For me,” said Reis, “the importance of the work is being able to take the intrinsic natural curvature of rods into account for this class of problems, which can dramatically affect their mechanical behavior.”

For him, sure. For anyone else—at least anyone carrying around a headful of perhaps 100,000 of those naturally curly rods—the matter is a little less theoretical. In those cases, give a nod to science, but computer models and algorithms are nothing compared to a good blowout and a little mousse.

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An earlier version of this story incorrectly identified the graduate student involved in the study as John Miller. His name is James.

TIME Viewpoint

Hawking: Is He All He’s Cracked Up To Be?

Professor Stephen William Hawking, CH, CBE, FRS, FRSA, at the Department of Applied Mathematics and Theoretical Physics, University of Cambridge..Photograph © Jason Bye.t:  07966 173 930.e: mail@jasonbye.com.w: http://www.jasonbye.com.
Stephen Hawking outside DAMTP, Department of Applied Mathematics and Theoretical Physics, Cambridge. Jason Bye / PBS

We all know that Stephen Hawking is the greatest living physicist—but what we all know may not be true

Partway through Hawking, a moving new PBS documentary on the life and work of British physicist Stephen Hawking, narrated via voice synthesizer by the man himself, Hawking raises a delicate point. “Sometimes I wonder,” he says, “If I’m as famous for my wheelchair and disabilities as I am for my discoveries.” He never offers a definitive answer, but it seems pretty clear that the filmmakers think it’s mostly about the discoveries.

Sure, the backstory is poignant, and even amazing—diagnosed with the muscle-wasting condition known variously as ALS, Lou Gehrig’s Disease and, in the U.K., motor neurone disease, Hawking was given just two years to live. Yet a full half-century later, after a distinguished career at Cambridge, the 71-year-old scientist, now utterly paralyzed, is still hard at work trying to solve the mysteries of the universe.

But it’s the discoveries that really catapulted Hawking into the pantheon of physics greatness, right? Trapped in an increasingly useless body, he could, as Caltech physicist Kip Thorne says in the film “move at lightning speed through the universe, seeing things nobody else could see.” He is, as most of us know, the greatest physicist since Einstein.

Except that he isn’t. “Rubbish,” Hawking himself responded, when I posed this proposition to him during a 1993 interview. “It’s mere media hype.” It’s undeniable that Hawking has made key contributions to both relativity and quantum physics. He came up with the insight that the Big Bang emerged from a singularity, a point so small and dense that the very laws of physics can’t describe it. He figured out what happened when black holes merge. He also came up with the startling and counter-intuitive notion that black holes can evaporate, slowly at first, then faster and faster until they explode—an idea that was at first ridiculed, but which is now mainstream. “This result,” says Bernard Carr, one of Hawking’s former PhD students, “unified relativity and quantum theory and thermodynamics.”

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That would be positively mind-blowing—if true. But it’s really not: the so-called “Hawking radiation” that should emerge from black holes draws on those disparate areas of physics, but “unify” means something else entirely. Unifying relativity and quantum physics is something Einstein tried to do for the last two decades of his life, and failed. The best bet for unification these days is string theory—assuming it turns out to be correct, which we may never know.

You can’t blame Hawking for that over-the-top quote, but Hawking himself talks about the honor he felt being inducted into the Royal Society. “My name,” he says “sat alongside Isaac Newton and Charles Darwin.” Well, yeah, and also along a lengthy list of other scientists you’ve never heard of.

Then there’s A Brief History of Time, Hawking’s mega-bestseller, first published in 1988. “I wanted the book to be read by millions of people around the world like a bestselling airport novel,” he says in the film. “I felt the mass market wanted to know how the universe began.” Fat chance, thought his agent and his publishers—but Brief History went on to sell millions upon millions of copies. The reason was that it explained some of the great mysteries of the cosmos in simple, digestible language. “It made this subject a topic of conversation among all walks of life,” says Caltech’s Thorne.

Surely you remember all those conversations. Or…maybe not. In fact, the book was nearly incomprehensible to people in all walks of life outside of theoretical physics. The real story, suggested Time book critic Paul Gray in a 2001 essay, is that “people buy a book for many reasons: either they want to read it, think they ought to read it, or want to impress people by making them think they have read it.” Whether they actually do read it is an entirely different question.

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None of this should suggest that Stephen Hawking is not one of the world’s leading physicists: he is, and would still be even if he were perfectly healthy. It’s the disability, though, and his fierce determination to carry on regardless, that makes the film so engaging and his life so uplifting—and perhaps makes people want to overstate his accomplishments. He is, one former student says, “the most stubborn person I know.”

Hawking chronicles that stubborn streak through Hawking’s own memories and through those of his sister, his first wife, and many, many colleagues. You don’t hear from his second wife, though: she was one of his former nurses, whom he ultimately divorced after 11 years of marriage amid scandalous rumors. “The press printed unsubstantiated allegations,” he says, “that I had been the victim of domestic violence. This was a gross invasion of our privacy.” (He doesn’t say, however, that it didn’t happen.)

The film is peppered with photos and videos of Hawking as a young boy, then a nerdy Oxford undergrad, then an increasingly disabled man who can now only twitch the muscles in his cheek to operate a computer and voice synthesizer. There’s also plenty of cheesy footage of actors recreating what Hawking might have looked like writing on a blackboard way back when—an unfortunate technique that’s now evidently de rigeur in historical documentaries.

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You also see flashes of Hawking’s sense of humor. It shows in his willingness to spoof his own smartest-man-on-the-planet brand with appearances on The Simpsons and Star Trek, and with his collaboration with Jim Carrey on a stunt call while the comedian was on the air with David Letterman (“I’m watching Dumb and Dumber, Jim, and you’re a genius.” “No, Stephen, you’re a genius.” “No, Jim, you are”). He’s also pretty funny in real life. “It’s a pity,” he says to a huge audience at a public talk, “that nobody has found an exploding black hole. If they had, I would have won a Nobel prize.” He delivers the line for laughs, and gets them.

And then there’s something that doesn’t make it into the film, but which I saw myself when I interviewed him in 1993. It was in Seattle, where he’d gone to give some talks, and his aide let it slip that whenever he traveled, he would ask his hosts to set up a meeting with local children with disabilities.

These visits were totally unpublicized, but I was lucky enough to go along and watch the pretty-great physicist answered questions from a half-dozen or so kids for an hour, their wheelchairs arrayed around his in a semicircle. That’s when I became convinced that even when you strip away the hype, Stephen Hawing may not be the world’s greatest living physicist—but he’s a pretty extraordinary human being.

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