14. Silicon: Tool Of All Trades

From prehistoric times right through today, our hand-held tools have been made of silicon.

Featured above: Diatoms, as seen through a microscope; or, silicon under silicon.

Show Notes

Long-Solved Mysteries: Old windows — like, really old ones, from the Middle Ages — are sometimes thicker at the bottom than the top, and a popular explanation is that glass is actually a slowly moving liquid. Given a couple thousand more years, the window panes might just slough off the wall entirely! Is this true?

Of course not. Glass is a noncrystalline amorphous solid, remember? The short explanation is that these windows were subject to gravity when they actually were in a flow state — i.e., when they were being created — which caused them to thicken up near the bottom. Scientific American has a more thorough explanation for the curious.

Self-Cleaning Glass: How does self-cleaning glass work? John Emsley’s new edition of Nature’s Building Blocks describes it simply:

…this is made by exposing the surface of molten glass to titanium tetrachloride (TiCl4) and steam, which react chemically to form a layer of titanium dioxide (TiO2) permanently bonded to the glass surface. The TiO2 absorbs energy from the sun and creates superoxide free radicals from the oxygen of the air. These convert organic dirt like grease on the glass to CO2 gas. Any inorganic dirt left behind is then easily washed away because the surface layer of titanium dioxide retains a film of water, unlike ordinary glass on which rain gathers as droplets.”

Fossil Cruel: Diatoms tend to leave their single-celled bodies behind after they die, sometimes en masse. There are locations on Earth where their bodies pile up hundreds of meters deep, leaving behind what’s known as “Diatomaceous Earth.” It has a number of interesting properties that make it useful, for instance, as a physical water filter, but it’s probably best known as a human- and pet-safe way to go after bugs. At scales that we and our furry friends operate, it just feels a little grainy, but at a bug’s size, it’s more like a bunch of needles that will pierce their exoskeleton and leave them desiccated.

Silicon’t: I mentioned that any silicon-based life would exhale silicon dioxide, which would be problematic at room temperature. Incidentally, if we breathe silicon, it’s just as bad. It’s actually not toxic, in a technical sense, but small enough granules of silicon can be taken up by the lungs and cause disease in a manner very similar to berylliosis. So, try not to!

The Real Chauvinist Is This Great Man: “Carbon Chauvinism” is a term invented by Carl Sagan, lest anyone think that’s an original idea of my own. He proudly declared himself such a chauvinist in his television series Cosmos.

The Fires Within: Here is the Arthur C. Clarke story promised in the episode, in both text and audio format. You can read it freely on Google Books, or listen to this video here. Please note that, despite what the video’s cover image says, his last name is spelled “Clarke.” But it’s a pretty decent reading!

For All Your Lunar Lander DIY Projects: The code for Apollo 11’s guidance computer is actually freely available on GitHub. If you’re so inclined, it makes an interesting history lesson — and some of the comments (within the code) are pretty good, too, like “TEMPORARY, I HOPE HOPE HOPE.”

Fable Finished: Either the paperclip example or The Unfinished Fable Of The Sparrows might strike you as patently absurd and not worth worrying about. Especially if that’s your reaction, it’s very worth picking up Superintelligence from your local library and giving it a read. Bostrum is not some manic street preacher — he’s given this a lot of thought, and he’s a very smart fellow. The book can get a little heady sometimes, but it’s still pretty accessible for the casual reader.

Holy Frozen Smokes: Aerogel is a strange, strange substance. In addition to being very light, and an excellent insulator, it’s also quite sturdy. All images are courtesy NASA and sourced from the Wikipedia article on aerogel. (I don’t use Wikipedia as a primary source for facts, unless I’m actually talking about Wikipedia, but it’s excellent for images.)

Ruin The Universe For Fun And Profit: Engage in a no-stakes version of runaway superintelligence, starring you, in Universal Paperclips. It’s slow and tedious to start, but I promise, it’s worth playing through to the end. (It’s also possible to irrevocably lose at a couple points, too, so you’ve been warned.)

Click To Read Transcript

Carbon is everywhere in our bodies, but silicon has always been in our hands.


  1. Chemicool, Silicon Element Facts. Dr. Doug Stewart, October 9, 2012.
  2. TV Tropes, Silicon-Based Life.
  3. Spectrum Online, The Lost History Of The Transistor. Michael Riordan, May 2004.
  4. Calculated assuming an original speed of 100mph, with 25 subsequent doublings, expressed as 100 * 2^25. Of course mathematical accuracy isn’t really the point here, but more the absurdity of scale.
  5. The Guardian, With Less Computing Power Than A Washing Machine.
  6. Popular Mechanics, How Do NASA’s Apollo Computers Stack Up To An iPhone? David Grossman, March 13, 2017.
  7. Communications Of The ACM, John McCarthy. Bertrand Meyer, October 28, 2011.
  8. Ethical Issues In Advanced Artificial Intelligence. Nick Bostrum, 2003.

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