jakub_h

Yes, what is called "gravity turn" turns the velocity vector, but if the rocket didn't actively reorient itself (so as to keep in line with the velocity vector), gravity itself wouldn't rotate the rocket (change its attitude), because almost-homogeneous gravity field won't impart (meaningful) momentum. (Satellites can actually use it that way, but the time constants are substantial and not really relevant for an ascending rocket on a timescale of minutes.)

However, this is independent of the presence of the atmosphere. In real life, both scenarios need active control of attitude.

It's not the case with a rocket, unless you're flying forward with a liquid propellant rocket and the fuel tanks are almost empty so that the center of mass is significantly behind the center of drag (and the atmosphere is appreciable). That is an inverted pendulum situation.

Outside of atmosphere and/or at low velocities, there's no instability of this kind, and "flying backwards" (=landing) makes the rocket actually auto-stable (like with a dart), even if the time constants may not necessarily be meaningful for useful control here.

No, it won't, because neither the thrust vector nor the gravity causes a moment in this situation. The key insight to the pendulum fallacy is actually that this situation doesn't create orientation-dependent momentum. That would make it a pendulum, but it isn't like that, hence the "fallacy" part.

Easily. The yardstick is unstable in inclination if it isn't vertical. The rocket is unstable in horizontal position if it isn't vertical. But it doesn't start to rotate as long as the thrust vector goes through the CG. The thrust vector has stable orientation relative to the rocket (if you don't gimbal), whereas the force vector doesn't have stable orientation relative to the yardstick.

They already figured out how to land on a moving barge, and they just did it.

How is even the landing an inverted pendulum problem? There's no instability of an inclined rocket during the landing; there's an instability of a "gimbaled-away" rocket. That's not the same thing.

However, since the US military recently labeled climate change as the #1 national security threat to the US or something like that, maybe we could hope for some climate science on the side? ;-)

And by "codes", you mean specific legacy software artifacts written in FORTRAN (note that I'm not even spelling it as Fortran)? Of course that's a problem.

No, it wouldn't (most likely): https://en.wikipedia.org/wiki/Jevons_paradox

In late 1980s, it was expected that by 2000, you'd have a GaAs computer on every desktop (powered by Occam or Prolog, of course ;-)). In the end, it turned out that silicon had more life in it than was expected, while being much cheaper and easier to manufacture.

If by "why not", you mean physical possibility, maybe because the UK is not going to become tropical again any time soon?

> It’s based on an ideological belief that one “race” is somehow better than another “race”.

I would actually think that the belief is, or at least used to be, scientific. Note that this is not a statement about the truth value of the claim, but the claim itself was or used to be posed in a way that referred to certain broadly quantifiable phenomena such as intelligence. That in itself is hardly "ideological". "Intelligence is good for a proper society", now that is ideological.

> tumblr.com

Oh my...

Well, of course it is a Common Lisp product. I haven't seen its internals but I would be surprised if it didn't use the features of CLOS+MOP to that effect, or, vice versa, if these features of CL weren't the very inspiration for that functionality. (Well, maybe Smalltalk could also achieve a similar level of seamlessness.)

It seems to me that least in a part of you argument, you seem to be confusing the deficiencies of particular implementations or server-run code with the idea itself. Stored procedures are bad because your RDBMS has a crappy compiler? Hmm...

(One might argue, of course, that SQL in itself turned out to be a lousy interface protocol for relational data processing, and that it caused a lot of pain to begin with. But that's a different topic.)

> Probably going to get downvoted to oblivion but redefining classes at runtime seems like a really bad idea - surely this just leads to undefined behaviour within your type system.

Technically, databases are doing that all the time - at least the more advanced ones like Firebird and PostgreSQL - you can transactionally change the schema, even while the DBMS is running, and you do not expect to lose old data in the process. The data gets even updated lazily. Interestingly, there's at least one database (AllegroCache) that uses this similarity between heap update and on-disk data update to great advantage to blur the distinction between transient and permanent data further still.

> If I pass an int to a method I don't expect it's type to be changed by said method.

"Ints" are immutable, largely even on a meta-level. Most of them (fixnums) in any program are even direct (not pointers), so no mutation would affect any callers as a side effect anyway even if it were possible. At best you can redefine methods specialized on numeric classes.

But I'm still learning these things, I hope I'm not spouting some nonsense here.

I guess it apparently depends on what definition of the word "word" (which is quite overloaded) one uses, though. I'm not quite familiar with English linguistic terminology but I believe it's more about sharing a radix than a root.

That "mini-ice-age" claim has been very quickly questioned by many. But the Gulf Stream reportedly exhibits strong signs of slowing down, which to me sounds like a much more important factor for the UK.

If I'm not mistaken, it's not "similar". It's literally the same word, just like the English "hound" and the German "hund". Meanings sometimes split, but the origin is the same.

On a near-noise level, virtually all conversation or interaction can and mostly does contain shades of meaning expressing things that when verbalized explicitly would be considered rude or inappropriate. From that POV, the term appears meaningless or redundant. Otherwise we'd communicate like Vulcans.

EDIT: I find it also peculiar that the explanation you've cited only mentions "racial slights", despite neither "micro-" nor "-aggression" containing this meaning. But it's comforting to know that one is at least safe from committing such things across all the other social boundaries! /s

Aren't people entitled to start a conversation with anyone they want? (Outside of some very traditional pre-modern societies where certain people are not even allowed at all to talk to certain other people, mostly by kinship.)

Micro-what?

Go uses runes... ;-p

I was talking about the root cause, not about the symptoms. The article claims that the alarms were caused by a "checklist error", when in reality, it was an analog interface mismatch caused by incomplete specification which two different teams interpreted sufficiently differently to cause a hard-to-debug hardware problem.

If Eyles doesn't mention Hamilton, it's probably because she wasn't involved in the particular functionality of the Apollo software that is being ascribed to her by many articles on the Internet and that is relevant to the Apollo 11 incident. In this particular article, it's not claimed explicitly by the author, but it is insinuated by the statement "I read that the Apollo would not have been able to land without your software." Well, of course, if she was a team lead on the software effort, the whole software is "hers" from a certain point of view, but that's sort of like giving whole credit to Bill Gates for writing Microsoft Windows. Mindell does mention her on several occasions, but in the software resilience area, he connects her to rigorous checking and prevention of erroneous user inputs, not to executive fault-tolerance. This functionality has proven critical on at least one occasion (when Apollo 8 astronauts mistakenly attempted to initiate pre-start sequence in mid-flight) but not in the incident in question.

I'm actually quite pleasantly surprised that we've already reached this level of functionality. Imagine aliens coming to our planet and starting classifying stuff on Earth. The idea that alien intelligence without some seeded knowledge would mistakenly make this inference doesn't seem beyond the realm of possibility.

That's exactly why I'm partial to Common Lisp. People can badmouth it as much as they want, but I'm still running Maxima on it, AND the application's language still isn't set in stone by design.

(You've also reminded me again that there's market for document-structure-reconstructing OCR.)

What about the claim about the actual cause of the Apollo 11 program alarms? What about the involvement of Hal Laning in the actual design and implementation of the real-time executive casually attributed to Hamilton in this article and some of the others on the web?

Have you read Digital Apollo by Dave Mindell? If not, do so. It is a much better researched text on the story of Apollo guidance, by a professor of aerospace history who works at the institution (MIT) formerly involved with AGC. In the meanwhile, the text at http://www.doneyles.com/LM/Tales.html will de-disinform you with regards to some of the article's mistakes.

Uh. There's so much wrong in that article that it hurts. Can't people actually research history more seriously?

What people mean when they say native depends on what people you're talking about.

What about crowdsourcing the job? I'm sure people would be willing to help.