Cosmos Recap: We Bet You Didn't Understand All The Stuff About Spectroscopy Either

This week’s episode of Cosmos, “Hiding In The Light,” is all about light and the spectrum, and how an assortment of scientists came to understand something about how light works. This episode seemed somehow shorter and jumpier than others in the series, though I’m not sure I can put a finger on why — maybe it’s just that there’s no single moment in this week’s outing that prompted an “Oh, WOW” as in some of the earlier outings. Even so, it’s still Neil deGrasse Tyson doing history of science, so that makes up for a lot.

We start off in ancient China, with the story of Mo Tzu, the showman in the video up top, who experimented with light and dabbled in the philosophy of science, including, unfortunately for the survival of his works, an insistence upon questioning all ideas and testing whether they can be verified and found to be useful. And then we see Mo Tzu’s books being burned by the first Chinese emperor, Qin, giving Tyson the opportunity to remind us that “Science needs the light of free expression to flourish. It depends on the fearless questioning of authority and the free exchange of ideas.” OK, freedom to question: good.

Next, on to Basra, Iraq, in the 11th century, and Ibn al-Haytham, or Alhazen if you like your Arabic names Latinized (we’ll go with the latter, since that’s the show’s pronunciation). In another mostly animated segment, we get a mini-lesson in the scientific achievements of the Arab world of those times — great, Neil, you’re not satisfied with pissing off the creationists? Now you’re going to stir up the Pam Gellers, too? But we learn about the role they played in preserving the knowledge of the ancient Greeks, and about their importation of what came to be called “Arabic” numerals from India, as well as the concept of zero, “which comes in handy when you want to write billions and billions.” Neil manages not to wink, at least. Among other discoveries, Alhazen discarded the idea that the eye sends beams of light with which it perceives the world — rather, he argued that light comes into the eye. He also determined that light moves in a straight line, and that the key to clear images is a small aperture to admit light — the secret to both the camera obscura and the eye’s pupil. In this telling, Alhazen (voiced by Alfred Molina) was also the first to lay out the basics of the scientific method, setting out a system of testing and sifting out errors, basing conclusions only on “argument and experiment,” and not in received wisdom.

Jump ahead a few more centuries, to Isaac Newton experimenting with prisms and almost — but not quite — discovering what happens if you focus a spectrum from a prism onto a magnifying lens. Tough luck, there. We see last week’s animated hero, William Herschel (sans guest voice actor Patrick Stewart) accidentally discovering infrared light in an experiment to see if the colors in the spectrum have different temperatures — the thermometer he used as a control showed an increase in temperature even though it was not placed in visible light.

And on we travel, to 18th-century Bavaria, and the hellish life of young Joseph Fraunhofer, toiling in the glassworks of Philipp Weichelsberger, where Joseph was both overworked and cheaply animated. Luckily, Weichelsberger’s workshop collapsed one day and Fraunhofer was literally rescued by Prince Maximillian, who took an interest in the boy and gave him the chance to study optics. Fraunhofer went on to make precision optics for the Bavarian military, and while experimenting with shining the refracted sunlight from a prism into a telescope, discovered the existence of dark lines within the spectrum, which turn out to correspond to the gaseous elements within the sun.

I’ll confess that Cosmos lost me a bit here — there’s a lot of pretty atomic-level animation of the electron in a hydrogen atom jumping around on a quantum level, and a kind of an explanation of how this is seen by spectroscopy, but I won’t pretend to have any deeper understanding of it than “you can tell what something’s made of by looking at its spectrum,” — which is about all a liberal arts monkey needs to know anyway. The how of it would require actual study — and for a pretty neat look at internet nerds trying to educate each other further, it’s a hoot to read the episode discussions on Reddit — but the why it matters is clear enough: look at a star’s spectrum, and you can tell what elements that star is made of. And it turns out that everything in the universe is made of the same elements — cue a reprise of the “we are made of star stuff” theme, complete with a visual quotation of the first series, the emblematic dandelion fluff blowing into the wind.

The episode closes with a brief mention of the mystery of dark matter — the stuff that seems to make up a big part of the universe, but whose properties are largely unknown — so far. “We only know it’s there because of its gravity,” which is driving the expansion of our universe. And then on to a rather sweet closing bit in which various kinds of light are represented by various visual effects superimposed on shots of New York City, accompanied by bits of Gershwin’s “Rhapsody in Blue,” eventually coming together in a fully-orchestrated picture. Pity, though, that thanks to a really good ad campaign, all I can think of when I hear that tune is United Airlines.

Cosmos: A Spacetime Odyssey airs on Fox 9:00 Sundays Eastern/Pacific, 8:00 Central/Mountain. Reruns Monday on National Geographic Channel 10:00 Eastern. Episode 5, “Hiding In The Light,” online at CosmosOnTV.com

TV Show: Cosmos

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  • Scooter

    Haha….I did understand all the stuff about spectroscopy (I’ve had plenty of astronomy courses in college) and here’s why it’s important: it gives us the ability to know that the entire universe is made of the same stuff. That stars billions of light years away are made of hydrogen and helium just like ours. It’s a profound discovery, not just in terms of chemistry and physics, but also of philosophy. Knowing the atomic make up of stars and planets allows us to make predictions about how they will behave. Philosophically, the more you understand of the universe and where your place is within the cosmos, the better you are able to act accordingly.

    • NoNotThatOne

      I agree spectroscopy is important for the reasons you mention, though I felt it was odd for the show to pick that particular subject for an in-depth explanation. Cosmos covers so many other important subjects with cursory explanations and grade school level details, and, for me, the segment felt like a showstopper. I suspect NDT was being a tad self-indulgent.

      • Yeah. A bit like Sagan dedicating a whole episode to Mars.

        • glasspusher

          The fucking nerve!

      • glasspusher

        Perhaps he just believed that his audience was capable of following along! He believes in you people!

  • Joey__Blow

    ““We only know it’s there because of its gravity,” which is driving the expansion of our universe”hmm no.. that is the other dark thing.. dark energy has started increasing the rate of expansion of the universe in the last billion years or so.dark matter binds the galaxies together and helped create them in the first place.

  • BaldarTFlagass

    “I’ll confess that Cosmos lost me a bit here”It’s okay, the high priests understand it and will tell you all you need to know.

  • BaldarTFlagass

    “cue a reprise of the “we are made of star stuff” theme”Which Mr Sagan stole from Joni Mitchel, as popularized by CSNY.”We are stardust, we are golden, we are billion year old carbon,And we got to get ourselves back to the garden.”

    • glasspusher

      Both Carl and Joni smoked more than their fair share of weed.

      • glasspusher

        “Just say no to tweed”Hmm. That was meant as a reply to SullivanSt below…

  • SullivanSt

    If you want to know the how of it, you need some sort of understanding of the solutions to Schrödinger’s equation (tells you the energy levels of electrons in an atom) and Pauli’s exclusion principle (tells you which energy levels are available for electrons to transition between)

    • glasspusher

      Look, pal, some guy with glasses and a lab coat does that. I make the deals.

      • SullivanSt

        No lab coat needed for theoretical physics, although many seem to find a sweater vest helps. Shudder.

        • glasspusher

          see above subthread

          • SullivanSt

            Nice move with the tesla coil BTW… Sounds more fun than the mass spec in the college chem lab (haha which did require a lab coat). I did manage to avoid tweed when I was taking TP courses, back before I realized it was too damn hard. Maybe geometric algebra was a mistake.

  • BaldarTFlagass

    “cue a reprise of the “we are made of star stuff” theme”Which Mr Sagan stole from Joni Mitchell, as popularized by CSNY.”We are stardust, we are golden, we are billion year old carbon,And we got to get ourselves back to the garden.”

    • He was probably stoned while he was listening and didn’t realize he stole it.

    • glasspusher

      I’m seeing double…

  • $73376667

    Fun spectroscopy fact: As you might guess by its name, helium was discovered in the sun before it was found on earth.

  • glasspusher

    I just gave a talk on spectroscopy to 5th fucking graders last week! I passed out diffraction gratings and they made their own spectroscopes, they could see the oxygen and nitrogen emission lines in the air from a spark made by a tesla coil I brought in. If they can do it, you can too!Doppler shift, line broadening, it’s all good.

    • Munchkn

      That is so cool, glasspusher! That’s the kind of science lesson that makes an impression on young minds.

      • glasspusher

        Yes it is. I was fortunate enough to have folks come in when I was back in public school on another coast, back in the day, and now it’s my turn to do it for others. I don’t forget those who helped me…

        • Munchkn

          Is it OK if I share your experience with my physics teacher brother? I think he’d like it.

          • glasspusher

            Absolutely!

          • Munchkn

            Thanks! And thanks for being a teacher. Your students are lucky to have a teacher like you!

          • glasspusher

            Well, uh, I’m not a grade school teacher. I was invited to come in and do my schtick by one of the parents. I do teach grad school one night a week, but it’s not my day job.

          • Munchkn

            Ah, I understand now. Still, it’s good that you teach adults. Anyone involved with teaching has my admiration.

    • essbird

      My dad brought home a high-end diffraction grating back in 1967 that someone in the factory had touched the corner of. With some wood, a razor blade for a slit, and a lens assortment from Edmund Scientific, I built a spectroscope that had a pointer and an Angstrom scale. A fluorescent lamp provided a beautiful mercury spectrum. I won the science fair. It was very cool. If you folks want to bring science to your kids, I recommend a sixties book from UNESCO called “700 Science Experiments for Everyone.” You will learn how to build real instruments from household junk. No electronics needed, you’re a scientist.

      • glasspusher

        Very cool. I need to get around to making a nice, calibrated spectroscope. I make my own telescopes, shouldn’t be a problem. Also, “the amateur scientist” from Sci Am is now available on CD, bought it a few years back, it’s a shame stuff like that went out of style, but what with hackaday.com and the maker movement, there’s a resurgence of home scientists these days once again! Huzzah!Also I grew up a 2 hour drive away from Edmund and one xmas vac my parents took us all there, it was very cool even in the 70s but unfortunately has forgotten the kids market and sold off their consumer stuff. My first scope was a 3″ edmund reflector, not so hot a mirror, but it kept me thrilled for over 2 years. $38 back in 1976!

  • DemmeFatale

    I love the way Neil purrs.And I love the thought of all those wing-nut heads asploding.Carmina Burana and Rhapsody in Blue? (This is MY idea of heaven!)