This weekend I'll be at Science Online 2013 in North Carolina, moderating a panel with io9's Annalee Newitz on science and science fiction. It's a topic near and dear to both our hearts, and Annalee kicked off a pre-discussion last week with her post exploring the evolutionary biology of Star Trek. I'd like to do the same by talking a bit about the history of how science has fed into popular culture over the years -- especially science fiction.

The prevailing scientific worldview of a given era has always been reflected in the art and literature of the time -- not to mention the theology. This was certainly the case in the 1500s, when the ancient Ptolemaic worldview still prevailed, with the Earth nestled at the center of the solar system, and the moon, Sun and known planets at the time revolving around it in perfect circular orbits. That movement was believed to produce a celestial music -- the "music of the spheres" -- undetectable to sinful human beings on the fallen Earth. Anything below the moon was "sublunary," separate from the rest of the solar system's state of grace.

Allusions to this worldview abound in Milton, Shakespeare, John Donne and many other leading literary figures, but by the time Sir John Davies penned his poem "Orchestra" in 1596, the Ptolemaic system was beginning to crack as the Copernican revolution gained momentum:

Only the earth doth stand forever still,

Her rocks remove not nor her mountains meet;

Although some wits enricht with learning’s skill

Say heav’n stands firm and that the earth doth fleet

And swiftly turneth underneath their feet

Ah, but then came the dawn of science fiction in the 19th century, beginning (arguably) in 1818, when Mary Shelley's Frankenstein was first published anonymously in London. (Fans of classic sci-fi from this era should totes be reading Skulls in the Stars; Dr. Skyskull is an expert on the subject.)

By the time Jules Verne's From the Earth to the Moon (1865) and H.G. Wells' First Men in the Moon appeared, science fiction was an established genre, one that inspired many young kids to dream of traveling to other worlds -- most notably rocket pioneers J. Robert Goddard and Werner von Braun, who helped launch the 20th century space program.

No longer was it just science seeping into the popular culture: now popular culture was inspiring scientists in turn. And then came film and television! Verne's novel inspired Georges Melies to make the first science fiction silent film, A Voyage to the Moon.

The 1950s was a veritable Golden Age of cheesy B-movie science fiction, and as the decades rolled on, you even had sly references to scientific breakthroughs showing up in mainstream films. Sure, it took a few decades, but Hubble's discovery that the universe was expanding went on to give little Alvy Singer nightmares in Woody Allen's Annie Hall:

These days, science is everywhere in film, TV, books, music, theater, art -- you name it. It's handy for people like me, who love to ferret out the science in popular culture -- or physicists like Jim Kakalios, whose book The Physics of Superheroes is a must-read for any lover of classic comic books. My own book (shameless plug alert!), The Physics of the Buffyverse, combed through episodes of Buffy the Vampire Slayer and its spinoff, Angel, to compare and contrast the science in Whedon's world with that of our own.

World-building in science fiction is all about establishing the rules of how your world works; it is artistically essential, because a world with no constraints has no conflict, and hence no story. Those rules might evolve over time, and inconsistencies invariably creep in, but they exist -- even in the Buffyverse which has its own thermodynamics of magic. There are costs incurred, consequences that must be paid, and above all, strict rules as to how and when it can be used. Willow even cites energy conservation in a Season 7 episode, declaring, "Magic works on physics!" At least, it does in the Buffyverse.

The Buffyverse (and much of popular culture in general) abounds in what I like to call "found physics": elements that perhaps aren't central to the world-building aspect, but nonetheless provide "teachable moments." For instance, in the Emmy-nominated “Hush,” the Gentlemen are fairy tale monsters that steal everyone’s voices, so their victims can’t scream when the creatures arrive to surgically remove their still-beating hearts. It's necessary because the Gentlemen are extremely sensitive to any kind of noise. Eventually, Buffy figures out how to get her voice back and emits a single loud, prolonged, and high-pitched scream that causes the monsters’ heads to explode, scattering green goo everywhere.

Sound can affect the heads of creepily cadaverous demons because it is mechanical energy. Still, it is not a simple feat for Buffy to cause the heads of the Gentlemen to explode. The secret is a precisely tuned frequency, combined with long duration, and lots of decibels. Every material object has a natural resonant frequency at which it vibrates. That’s why running your damp finger along the rim of a crystal wine glass produces a faint hum.

We're basically talking about forced oscillation resonance: if an object has a particular natural rate of vibration, and if one pumps in more energy of the same resonance, the object will vibrate so strongly it can shatter, just like the wine glass in those old Memorex commercials.

Similarly, the Gentlemen’s exploding heads would have to have a resonant frequency perfectly matched to the pitch of Buffy’s scream in order for this to happen. Buffy’s sustained scream would probably have to be at least 135 decibels in order to generate sufficient mechanical vibration to cause them to explode. Unlikely? Sure. But it's good enough for Purposes of the Plot.

Of course, there are plenty of groan-worthy gaffes in the Buffyverse, too, as there are in just about any form of popular entertainment that dares to inject a bit of science. That's why nerd-gassing is such a popular and time-honored pastime among the geekerati. I went to see J.J. Abrams' Star Trek reboot with five PhD physicists, and the post-movie nerdgassing reached Olympic proportions. Their unanimous conclusion: "Red matter" didn't have to happen.

Some people are in favor of this kind of sci-fi handwaving, as detailed in this post by Steven Padnick at I think Padnick is right in principle (science fiction should stretch the imagination and look beyond what is currently possible, and you don't want to bog down your story with lengthy technical explanations) and wrong in the specific example of red matter, which is so ridiculous that it actually pulls the viewer out of the story -- something no self-respecting creator of a fictional world wants to do.

For an example of an error that still works in the fictional context, consider this scene from Third Rock from the Sun, in which visiting alien Dick Solomon -- now a physics professor -- finally proves his career isn't, like, totally boring and useless when he gets a criminal to confess using physics:

Dick: Using Coulomb's Third Law, I was able to prove that he did it.

Tommy: What does that have to do with it?

Dick: Nothing. All I proved was that he's rotating around the sun, but he didn't know that. That's the wonderful thing about physics, nobody understands it.

Sally: So you can use your knowledge to bully people into submission.

Dick: That's the plan. As long as America's educational system remains woefully inadequate, I rule!

The physics literate no doubt spotted the problem: the writers have conflated Coulomb's Law with Newton's Law of Universal Gravitation. Both employ the inverse-square law, and whether we're talking about electrons moving around an atomic nucleus or planets moving around the sun, we're still dealing with spherical objects with point charge and point mass. But Newton's law deals with very large mass, while Coulomb's law deals with objects with little mass but large charges. Also, gravitation is just attraction; Coulomb's law incorporates both attraction and repulsion. Here's the thing: the scene still works. When it comes to scientific bloopers, this one's a misdemeanor.

The science should always be in service to the narration, but it's always marvelous when you can both tell a terrific story and have it be reasonably accurate. Some of the best examples include such classic films as Contact and Apollo 13 -- and a lesser-known portrayal of the invention of the atomic bomb, Fat Man and Little Boy. My favorite scene depicted a famous experiment dubbed "tickling the dragon's tail," in which physicists tried to find the critical mass points of different materials to see which would be the best choice to set off the first stage of a nuclear chain reaction.

Needless to say, it was incredibly dangerous, yet Manhattan Project scientists sometimes skimped on the safeguards -- like removing the shims separating the two halves of the beryllium sphere housing the plutonium core. John Cusack's character is based on a physicist named Louis Slotin, one of two men who died as a result of botched criticality experiments. The first was in August 1945; at the time, Enrico Fermi told Slotin, “Keep doing these experiments the way you’ve been doing them, and you’ll be dead within the year.”

Fermi's fears were realized. A few months later, Slotin was using a screwdriver to tweak his experiment, when the screwdriver slipped and the two halves of beryllium came together for a moment, producing an intense burst of hard radiation. Fat Man and Little Boy recreates that moment in exquisite detail, right down to marking where each man was standing at the time of the accident (so the different doses of radiation received by each could be calculated) and removing all metal from their persons. Only Slotin, who manually separated the spheres and stopped the reaction, died. Horribly. Within nine days.

The current fictional descendent of Dick Solomon is Sheldon of The Big Bang Theory, currently the top sitcom in the US, garnering a whopping 19 million viewers for a recent episode (that's on a par with Friends, one of the most popular sitcoms of all time). The show has its own physicist as a technical adviser -- UCLA's David Saltzberg -- and its writers are justly proud of the fact that the equations on the whiteboard, the posters, books, and other props are drawn from actual physics departments.

But the geekerati are never satisfied; where's the fun in that? There are frequent objections to the show's stereotypical characters: socially awkward, poorly dressed, pining for unobtainable women, and so forth. I usually point out that the depiction is exaggerated, but not necessarily 100% wrong (we've all run into a real-world version of Howard Wolowitz), and comedy thrives on exaggeration. The nerdy guys actually get the girls in the end (well, except for Raj, who complains at one point that he never thought Sheldon would get a girlfriend before him). And Sheldon is a sex symbol among the fandom: he is by far the most popular character, as any attendee of the annual Big Bang Theory panel at Comic-Con can attest.

In one classic scene, Sheldon uses the paradox of Schroedinger's Cat to give Penny advice on whether or not to go on a date with Leonard and give their budding romance a chance. (You can watch the clip here; embedding is disabled.) Never mind that nobody should be seeking advice on love from Sheldon; his explanation is dead-on -- and also works really well metaphorically. Personally, I'll take Sheldon's loveable nerd over Flash Forward's cringe-inducing scene where sleazy quantum physicist Simon uses Schroedinger's cat to pick up a young woman on a train:

There is a time-honored tradition of satirizing scientists: back in 1676, Thomas Shadwell wrote a play called The Virtuoso, with bumbling, pedantic character based on Robert Hooke of Micrographia fame. The caricature was so dead-on, Hooke exclaimed in a letter, after attending a performance, “Dammd Doggs. Vindica me Deus, people almost pointed.”

Sometimes whether or not you accept the scientific premise of a film depends on your perspective. The Time Lord and I loved Inception, and shared our enthusiasm with psychologist Carol Tavris over dinner one night. We especially savored the careful attention to physics details, notably a scene in an elevator that served as the perfect cinematic depiction of Einstein’s equivalence principle. Check it out:

It's a great example of using physics principles in a "what if?" kind of way to explore how the rules could change (or not) in the dreamscape. But for Tavris, the very premise – that the most difficult thing to accomplish is to implant an original idea in someone else’s mind, such that they believe it is their own (the “inception” of the title) – was ludicrous, making it impossible for her to suspend her disbelief. “Inception is easy,” she declared.

It is the issue of authorship that is significant. The film makes clear that planting an idea in someone’s head is simple enough: tell someone not to think of pink elephants, and chances are that images of pink elephants will spring to mind. But they know that the pink elephants came from an outside suggestion. Tavris’ point was that it is just as easy to manipulate someone into thinking the pink elephants were their idea all along, and there's a lot of psychology research to back her up.

Finally, sometimes long-discarded scientific ideas can come full circle and find their way back into fiction. Remember the music of the spheres? We no longer adhere to the Ptolemaic cosmology, but the notion is still inspiring science fiction, as in this special episode of Doctor Who (penned by Robertson Davies):

The Doctor's explanation is an extrapolation of something very real: there is indeed a kind of "music" in the universe, and we can "hear" it through techniques like sonification -- like this video showcasing the sound of Saturn's rings, based on data collected by the Cassini spacecraft. It sounds very similar to the sound effects in that Doctor Who clip.

As Nobel laureate Frank Wilczek and Betsy Devine observed in Longing for Harmonies: “The marvelous dream [of the music of the spheres] is in fact closely realized in the physical world. The spheres, however, are not planets, but electrons and atomic nuclei, and the music they emit is not in sound, but in light…. If our eyes were more perfect, we would see the atoms sing.”