5G, the “fifth generation” cell phone standard, has been in the news a lot. There are people suspecting 5G of causing the coronavirus, and even reports of some of them burning cell phone towers in the UK. But this bizarre suspicion was by no means the start of the bullshit about 5G. Indeed, it’s a natural reaction to the previous over-hyping.

Two and a half centuries before Trump, there was…

One thing I didn’t understand until recently was why there was any interest in detonation engines for rockets – those being engines where the fuel is not burned smoothly but rather mixed and then detonated. I’d heard of the idea before, but it seemed such a bizarre concept that I didn’t pay it much attention. Yet there is considerable interest in such engines; they’re currently making headlines as a new, promising way to increase the specific impulse of rockets, and well-funded teams have been working on them and reporting successes. Specific impulse (\(I_{sp}\)) is the most important figure of merit there is for a rocket engine, and increases of 15% or even 25% are talked of. The concept is not really new: they’ve been talked about since the 1950s, and have been “promising” for all that time (and not delivering). On looking into the concept, it seems to me that even the theory is in error here, and that scarcely any improvement is in fact possible.

There are two math subjects taught in high school which involve the students doing a lot of proofs: geometry and trigonometry. Advocates say that it’s important for students to do proofs, since they are the bulding blocks that are used to construct the whole edifice of mathematics. Though the latter is true, the former does not at all follow from it. The edifice has already been constructed; students can simply live in it, rather than being tasked with rebuilding it. And the proofs taught in those two classes are amazingly useless.

As I argued a month ago, there’s no fundamental reason that putting out a vaccine for the coronavirus should take the “more than a year” or “at least 18 months” that is commonly quoted; those numbers come from the assumption that we’d follow the usual rules. At the same time, though, there’s considerable experience and wisdom incorporated into those rules; the idea shouldn’t be to discard that wisdom, but rather to understand it and adapt it to the emergency.

A critical question as regards the new coronavirus has been to what extent it is transmitted by asymptomatic people. But really there isn’t just one definition of “asymptomatic”. Instead, there are several possible definitions, each of which is useful in a different way:

Since hearing that there’d been 47 protesters killed in one day on the Maidan in Ukraine, shortly before President Yanukovych was forced from office, I’d idly wondered how it happened. Then, a couple of years ago (this blog is seldom timely), I ran across the video compiled by Evelina Nefertari which takes video clips taken by wide variety of people on that day and combines them into a single time-synchronized video stream showing many clips simultaneously.

The killings are commonly described as a massacre, but watching the video (and viewing maps and summaries of the action), a very different phrase seems much more apt: an infantry assault – and not an assault on the protesters; an assault by the protesters.

The phrase “history is written by the winners” is commonly uttered these days, which goes to show how many people repeat things without thinking about them, since a moment’s thought would reveal that it is incorrect. Plenty of history has been written by losers, for any and every meaning of the word “loser”. Many histories of the Civil War were written by the defeated Confederates, and the influence of those histories continues even today. Defeated Germans likewise wrote memoirs of their World War II experiences – memoirs which have not always been believed by the victors, but which in some respects have been and deserve to be.

There are people who look down on puns, and scold others for making puns, saying that they’re not funny.

I’ve been reading about oxygen therapy, and at first was a bit surprised how inefficient it is. The actual human use of oxygen at rest (the amount that gets used as an oxidizer and ends up as CO2 or water) is about 0.25 liters per minute, yet oxygen concentrators meant to adequately supply a single person normally put out about 5 liters per minute. And although the oxygen concentration coming out of the machine is 90% or so, inefficiencies in the way it is actually delivered to the mouth and nose reduce that to where patients are usually breathing a concentration of less than 50% oxygen (as compared to the normal 20% oxygen concentration of the atmosphere).