Oct 8, 2019
Cosmos Recap: And Thus Concludeth Neil DeGrasse Tyson's KAPOW! BLAM! SHAZAM Of All The Idiots
Here it is Thursday already and we’re only now bringing you your recap of the series finale for Cosmos: A Spacetime Odyssey. Happily, on the Cosmic Calendar, it was hardly a delay at all. But here we are, at the final episode, “Unafraid of the Dark,” which focuses, appropriately enough, on all the stuff we don’t know about the Universe. But we’ve got some terrific questions.
The episode begins with another shoutout to Carl Sagan’s original series, with Neil deGrasse Tyson walking through a CGI recreation of the Library of Alexandria. Like Sagan, Tyson tells us that ships stopping in the port of Alexandria were searched, “not for contraband, but for books” that could be copied and added to the Library’s collection. And then, a coda that was not available to Sagan: Tyson adds that the Internet is our Library of Alexandria, and — even better than the original — it’s not just available to the elite, but to everyone. Ah, but “what will happen the next time the mob comes?” It’s almost as if he thinks there are people out there who don’t much care for knowledge.
This is a farewell episode, so Tyson reminds us we’ve traveled from the tiniest places — the atom — to the furthest corners of the Cosmos. And now, let’s try a thought experiment. Imagine that somewhere, orbiting some star, there’s a world, and on that world, there’s a species that’s evolved intelligence, and furthermore,
there’s a subgroup of that species who believe they have it all figured out: their world is the center of the universe, a universe made for them. And that they know everything they need to know about it. Their knowledge is complete. How seriously would you take their claim?
At this point, we kind of lost the thread, because we had no idea what Tyson might be getting at. Oh, yes, science. That was us, and we still say the sun rises. Got it. Tyson shows us a 1492 globe made by Martin Behaim, missing the New World altogether, but thought at the time to be a complete model of the world. We think what Tyson is getting at is that people sure were dumb and arrogant back then, but we aren’t anymore, so we WIN. Or else he’s saying that compared to what Behaim didn’t know about his world, there’s a hell of a lot more we don’t know about our universe, because we’re only figuring out now how much more we don’t know… and that, kids, is an adventure.
Time for an animated segment, with Victor Hess discovering cosmic rays by going up in a balloon, and finding radiation at 3 miles above the earth — and from there, on to Fritz Zwicky, “the most brilliant man you’ve never heard of,” who determined that those rays came from supernovae, and also predicted the existence of neutron stars, pulsars, and the ability of a galaxy’s gravitational mass to bend light. And just to be a smartass, he even predicted dark matter in 1933, and turned out to be right about that, too. Here, Tyson brings in another woman in astronomy (thankfully, not just limited to that one episode), astrophysicist Vera Rubin, who was the fist to observe that, unlike planets orbiting a star at different speeds, the outermost stars of galaxies orbit the galactic center at the same speed as those closer to the center, which turned out to be the first evidence that some other gravitational mass was at work: Zwicky’s dark matter. Suddenly, we have all this damned matter in the universe that we haven’t begun to figure out how to make sense of…so far.
And then there’s dark energy, which is even weirder. Here again, we’re dealing with supernovae, whose distance can be tricky to calculate, since one type of supernova — the ones that result from collapsing stars — can vary widely in brightness, based on the mass of the dying star. But another type of supernova results from a binary system of a dwarf star paired with a giant; the dwarf strips gas from the outer atmosphere of the giant until the accumulation explodes, and these supernovae always have the same brightness, “about 5 billion times the brightness of our Sun.” And since all such supernovae have the same intensity, they’re perfect for measuring intergalactic distances; with the same goofy understatement that gave us the “Big Bang,” such stellar kablooies are called “standard candles.” By measuring the rate at which the universe is expanding, using those supernovae, astrophysicists determined that the universe’s rate of expansion is actually increasing, and to explain that, we’ve got dark energy. And then a commercial break. Waitadamnminute, I wanted to know more about the dark energy! Tyson says that “dark energy” is “merely a codewode for our ignorance,” and reassures us that “it’s OK not to know all the answers,” since “pretending to know everything closes the door to find out what’s really there.” Fine, fine, but at least could we have a little more of what it is that we have figured out about this stuff? This is one of those moments where — even in the finale — it feels like Tyson is rushing us along to the next exhibit before we’ve had a chance to read the card on the last thing.
Next, a review of the Voyager missions, the two spacecraft that have travelled the farthest of any human-made probes. Much discovery, very CGI, so cool planetary science. We learn about Voyager 1’s departure from the heliosphere, the outer reaches where the charged particles of our Sun’s solar wind collide with the bombardment of cosmic rays from deeper in space. The heliosphere’s size varies with the intensity of the Sun’s output of radiation, and with the strength of cosmic rays coming from “nearby” supernovae, sometimes even retreating toward the sun and leaving Earth exposed to cosmic rays. This happened as recently as 2 million years ago, evidence of which is trapped in manganese nodules found on the deep sea floor. It’s a lovely answer to the bonehead creationists who encourage children to ignore science by asking, “How do you know? Were you there?” Says Tyson, “The difference between seeing nothing but a pebble, and reading the history of the Cosmos inscribed inside it, is science.”
On those spacecraft, of course, are the famous golden records, messages sent to some far-distant salvage operators, coded in a language based on the hydrogen atom, showing the finders where our Sun is in relation to the 14 nearest Pulsars. The record is loaded with music, sounds, voices from Earth, including Carl Sagan’s son Nick, then six, saying “Hello from the children of planet Earth,” and as Tyson discretely describes it, “the brain waves of a young woman, newly fallen in love” — that brain belonging, as it happens, to Anne Druyan, who met Carl Sagan while working on the Voyager record, and fell in love with him. How about a digression, from NPR’s Radiolab, of Druyan telling the story:
And if you have 17 minutes, why not listen to the golden record yourself?
All this Voyager stuff is a set-up, of course, for the big inspirational setpiece, Carl Sagan reading the “Pale Blue Dot,” his name for the image of Earth as seen when Voyager turned around and snapped a selfie of our world from the orbit of Saturn. It’s one of those nerd texts that’s always guaranteed to bring the tears, every single time, and here it is once more:
Sunday night, Kid Zoom and I just sat together and watched that, holding hands, feeling very human and connected to each other and to one of the better minds our often-stupid species has managed to put forth. Kid’s pretty tolerant of his sentimental old nerd dad, all in all. (Kid Zoom adds: “It’s a pretty badass speech, and I wouldn’t fault anyone who breaks into tears during that.” He’s a good one, that Kid.) In a sense, part of the fun of this show has been thinking about the legacy of science, of knowledge being passed on and revised, and overturned, from one generation to the next, even as Neil deGrasse Tyson takes over the TV-science-guy inheritance of Carl Sagan.
Ah, but this isn’t quite the end. Tyson wraps up with a reminder of where we’ve come from — Giordano Bruno’s dreams of a universe with a multiplicity of suns and worlds, William Herschel telling his son (fathers and sons again!) about the light from the stars having originated long in the past, and then reminds us of the simple rules that make science work:
- Question authority. No idea is true just because someone says so — including me. Think for yourself.
- Question yourself. Don’t believe anything just because you want to. Believing something doesn’t make it so.
- Test ideas by the evidence gained from observation and experiment. If a favorite idea fails a well designed test, it’s wrong. Get over it.
- Follow the evidence wherever it leads — If you have no evidence, reserve judgment.
- And perhaps the most important rule of all: Remember you could be wrong. Even the best scientists have been wrong about some things.
“Science,” Tyson sums up, “is a way to keep from fooling ourselves — and each other.”
It’s a hell of a nice ending to a series that I had my doubts about. But this new Cosmos deserves a place on your nerdshelf right next to the original. In a lovely grace note, the series ends with a reminder that science belongs to all of us — that’s how we keep the mob away. In the series’ final sequence, we return first to the seashore where Sagan, and then Tyson, began their versions of Cosmos, and then to the “Ship of the Imagination,” the captain’s chair now empty, waiting for a new pilot to take the helm.
Cosmos: A Spacetime Odyssey on Blu-Ray, $29.99
Episode 13, “Unafraid of the Dark,” available online at CosmosOnTV.com