What more useful thing would you be doing with that time, if you weren't wasting it on pushing buttons?

You're also talking about fundamentally different kinds of rocket boosters. The Space Shuttle used solid fuel boosters, which are basically nothing except a tube packed full of energetically burning material, an igniter to light said material, and a nozzle for the generated gases to come out. They couldn't throttle, couldn't gimbal, couldn't shut off or restart, didn't use cryogenic fuel so didn't need insulation, didn't rely on pressurized fuel so they didn't need turbopumps... In fact, as far as I know they basically didn't have any moving parts at all!

You ever flown a model rocket, like an Estes? That little tube of solid grey gritty stuff that you use to launch the rocket is basically a miniature version of the solid fuel boosters on the Space Shuttle. The shuttle boosters were obviously bigger, and were a lot tougher (which made them unacceptably heavy for something like the Falcon 9's first stage) so they could survive the water landing, but fundamentally they were basically just cylindrical metal tubes with a nozzle at the bottom.

Despite that, reconditioning them for re-use was still so expensive that it's unclear if the cost was worth it. Now, of course, they cost a lot less to build than a Falcon 9 first stage, but every one of the Falcon 9 first stage's nine Merlin 1D engines is many times as complicated as the entire solid booster used on the Space Shuttle. Even the first stage tank is much more complicated, since it needs to take cryogenic fuels and massive internal pressurization.

I've decided to work on getting rid of a trivial useless habit: pushing pedestrian crossing buttons more than once.

Now, there's an argument that it's not completely worthless to do so: the typical button has no feedback whatsoever that it's recognized my push, so if it is at all unreliable then an extra push reduces the chances of a complete extra cycle wait at little cost to me since I have nothing else to do.

But the failure case has never actually happened in recent history, so I'm spending too much time pushing buttons.

So far I have remembered to push only once out of about ten times (2-3 per day). Of course, I immediately remember this resolution right after pushing twice.

I agree that a cache can be thought of as involving names, but even if -- as you suggest, and it's a good point that I hadn't considered in this context -- you sometimes have some scope to choose how much information goes into the keys and hence make different tradeoffs between cache size, how long things are valid for, etc., it seems pretty strange to think of that as being about naming.

At least one of us is confused. It never occurred to me that the original comment was intended as a joke (except in so far as it's a deliberate drastic oversimplification) and I don't think I understand what you mean about cacheing being subsumed by naming (especially as the alleged hard problem is not cacheing but cache invalidation -- which seems to me to have very little to do with naming).

I'm probably missing something here; could you explain your interpretation of the original comment a bit more? (With of course the understanding that explaining jokes tends to ruin them.)

To speak to the second of naming things, I'm a big fan of content addressable everything. Addressing all content by hash_function(<the content>) has major advantages. This may require another naming layer to give human recognizable names to hashes, but I think this still goes a long way towards making things better.

You might find Joe Armstrong's The Mess We're In interesting, and provides some simple strawman algorithms for deduplication, though they probably aren't sophisticated enough to run in practice.

(My roomate walked in while I was watching that lecture when I had headphones on, and just saw the final conclusion slide:

• We've made a mess
• We need to reverse entropy
• Quantum mechanics sets limits to the ultimate speed of computation
• We need Math
• Abolish names and places
• Build the condenser
• Make low-power computers -- no net environmental damage

And just did that smile and nod thing. The above makes it sound like Armstrong is a crank, but it all makes sense in context, and I've deliberately copied just this last slide without any other context to try to get you to watch it. If you like theoretical computer science, I highly recommend watching the lecture.)

Does anyone have any good web resources on how to be a good community moderator?

A friend and I will shortly be launching a podcast and want to have a Reddit community where listeners can interact with us. He and I will be forum's moderators to begin with, and I want to research how to do it well.

If the effect of RF doesn't go beyond thermal, then you probably shouldn't be concerned about sitting next to an antenna dish any more than about sitting next to light bulb of the equal power. At the same time, even if the effect is purely thermal, it may be different from the light bulb since RF penetrates deeper in tissues, and the organism may or may not react differently to the heat that comes from inside rather than from outside. Or it may not matter - I don't know.

And apparently, there is a noticeable body of research, in which I can poke some holes, but which at least adheres to basic standards of peer-reviewed journals, that suggests the existence of non-thermal effects, and links to various medical conditions. However, my background in medicine and biology is not enough to thoroughly evaluate this research, beyond noticing that there are some apparent problems with that, but it doesn't appear to be obviously false either.

A lot of math and physics definitions feel like they have weird dross. Examples:

• The Gamma function has this -1 I don't understand
• The Riemann Zeta function ζ(s) negates s for reasons beyond me
• cosine seems more primitive than sine
• The gravitational constant looks like off by a factor of 4π
• π seems like half the size it should be

After years of confusion, I was finally vindicated about π. That π is not 6.2831853071... is mostly a historical accident. Am I "right" about these other definitions being "wrong"? What are other mathematical entities are defined in ugly ways for historical reasons?

It is 11:30 by my clock, so published on Wednesday, though perhaps not at the time I had in mind ;)

Thanks again to Ari Rabkin, Peter McCluskey, Christian Kleineidam, Carlos Serrano, Daniel Light, Harsh Pareek, and others for helpful comments on drafts.

An amusing typo I discovered while proofreading one of the new parts of this post: one sentence originally read "when presented with a choice, it is often better to make out than not make one." Words to live by.