A diabolical psychologist brings a mathematician in for an experiment. The mathematician is seated in a chair on a track leading to a bed on which there is an extremely attractive person of the appropriate gender, completely naked. The psychologist explains “This person will do absolutely anything you want, subject to one condition: every five minutes, we will move your chair across one-half of the distance separating you.”
The mathematician explodes in outrage. “What! It’ll take an infinite time to get there. This is torture!” They storm out.
The next experimental subject is a physicist, who sits in the chair and gets the same explanation. “Awesome!” says the physicist. “Let’s get started!”
The psychologist is taken aback. “You do realize that you’ll never get all the way there, right?”
“Oh, sure,” says the physicist, “but I’ll get close enough for all practical purposes.”
This week’s episode of Cosmos went from the whopping huge to the very small, working their way down from tardigrades to nuclei. This was front-loaded with a bunch of biochem content, and only got around to physics and astrophysics much later.
As always, the visuals were spectacular, particularly the animated microscopic organisms. I was a little puzzled, though, by the decision to go from a quasi-photographic rendition of plant cells and orgnelles to a visualized metaphorical machine representing the action of photosynthesis. I mean, it was nice animation, and all, but kind of jarring after all the very literal stuff that came before it.
There was less historical content in this one, which is probably to the good. There was a slightly overdone bit about Darwin predicting the existence of long-tongued insects to pollinate particular species of orchid (which is mentioned in the Origin but not given especially heavy emphasis). And there was the obligatory call-back to the ancient Greek atomists, where they deserve credit for not just starting with Democritus, but going back to Thales a century or so earlier. The Greek cartoons got in the obligatory anti-religion message, and suffered from the usual problem that the ideas of the atomist Greeks were not actually all that similar to the modern concept of atoms. It wouldn’t be the Cosmos reboot without some annoyingly ahistorical content.
The “Keanu whoa” moment for the week was the claim that we never really touch anything, since the electromagnetic repulsion between molecules making up solid objects means there’s always a microscopic space between even objects that appear to be in contact. Which is true enough, but mostly just reminds me of the joke at the top of this post.
I was mostly okay with the discussion of atoms and nuclei; it could’ve used more quantum-mechanical content, but I suspect they think they got that out of the way last week. I will note that it’s not really hot enough in the core of the Sun (according to our best models) for protons to be moving fast enough to directly come in contact and fuse– you can calculate the necessary temperature for the distance of closest approach of two positive charges to be on the scale of a nucleus, and it’s around 15,000,000,000 K. The actual temperature of the Sun is more like 10,000,000 K. But quantum mechanics allows a tiny probability for one proton to tunnel through to the other, and allows fusion to proceed. That, to my mind, is more awesome than the “We never really touch anything”stuff, but then, I’m a physicist.
The last bit was about neutrinos, both as an element of observational astrophysics– shoutout to an animated supernova 1987a, but as usual none of the actual photos of the supernova outshining everything else– and as a possible probe of the early universe through the relic neutrinos created in the Big Bang. This was illustrated with a Wolfgang Pauli hologram, but next to no detail about Pauli himself, which I found a little disappointing because he’s an entertaining figure. Fun trivia: his famous prediction of the existence of the neutrino as a desperate remedy for the problem of beta decay (the explanation of which was a little garbled, but whatever) was via a letter sent to a conference that he was skipping because he wanted to attend a ball in Zurich. So much for the image of the antisocial physicist…
Anyway, a mostly good episode. The gaps in the science were either biological things that I didn’t notice, or subtle-ish points of physics that nobody else will notice. I could’ve done with less “matter is empty space!” and more quantum physics (or a discussion of Rutherford, because I never get tired of Rutherford), but I’m probably in a small minority there.