Cosmos: A Spacetime Odyssey, Episode 2, “Some of the Things That Molecules Do”
If I had to pick one word to describe this episode, it’d be “overstuffed”. Granted, the series has a huge amount of territory to cover; and unlike the original Cosmos, which aired on PBS, this one is subject to the ever-growing commercial demands of Fox, giving it just 44 minutes of television in an hourlong slot. Even so, it seemed to be straining at the seams to fit in every story it wanted to tell.
The episode starts out with the story of how humans turned wolves into the many different breeds of dogs, an example of the power of selection that even creationists don’t deny. (As further evidence of the plasticity of nature, here’s another of my favorite examples of artificial selection: broccoli, cauliflower, kale, cabbage, collard greens and Brussels sprouts are all domesticated versions of the same wild species, Brassica oleracea.)
We’re shown a montage of how the eye evolved in Cambrian seas, from a simple light-sensitive spot to a true pinhole-camera eye with a lens, refuting creationist claims of how “half an eye” would be useless. This sequence did a good job showing the selective advantage of each step, although the split-screen presentation – one side showing the physical changes wrought by natural selection, the other showing what the world looked like through those evolving eyes – was a good idea in principle but strained my attention trying to keep up with it. (We also briefly glimpsed one of my favorite Cambrian animals, the weird and fearsome Anomalocaris.)
The straightforward, no-nonsense explanation of how evolution works was very good, and I loved the Tree of Life – a visual metaphor in the form of a gigantic tree whose branches are adorned with representatives of all the species that have ever lived. That said, I thought the Fantastic Voyage-esque trip into the DNA of a polar bear, where Tyson’s spaceship shrunk down to molecular size to show a mutation in progress, was done more for the cool factor than because it added anything to the science. The animation showing the selective advantage of white fur would have sufficed.
But I loved the “Halls of Extinction”, a sepulchral pyramid whose corridors open onto rooms that show past mass extinctions on Earth. I’d gladly watch a spinoff about this place, and since Tyson conspicuously called attention to one hallway that was unmarked, I presume the series will revisit it later. (I assume the unlabeled corridor was the human-caused mass extinction that’s currently in progress.) I was a little surprised by the unambiguous presentation of the Permian-Triassic extinction as caused by volcanism, something I thought was still a topic of active debate among scientists.
The other high point was Tyson’s trip to Saturn’s moon Titan: its icy shorelines, its methane and ethane rains, and a submarine voyage into the largest of the frigid moon’s hydrocarbon seas, the Kraken Mare (and how awesome is that name?), ending with a tantalizing speculation about whether strange life may lurk down in the depths, using chemistry unknown on Earth. This was a place where the improved special effects really shine, helping viewers visualize something they probably couldn’t picture otherwise.
Since this new series has gone out of its way to pay tribute to Carl Sagan, I’m surprised that the episode didn’t mention one of his most important scientific contributions: his discovery that the orange haze which shrouds Titan is made up of tholins, complex organic molecules that are produced in the upper atmosphere by lightning and ultraviolet radiation and fall to the surface like snow. Again, time constraints may have been a factor here, but I think that would have been a more fitting ending than the one they did go with, the animation of humanity’s evolution from the original Cosmos. It was a not-unwelcome bit of nostalgia, but it could have been trimmed for a tighter focus on the truly striking visuals and ideas this episode presented.
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