Formerly u/CanadaPlus101 on Reddit.

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Joined 2 years ago
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Cake day: June 12th, 2023

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  • I’m actually not sure about the “one big touchscreen” idea - it’s seems likely some designer considered it, but even Star Trek TNG PADDs had more than one touch display segment.

    Portable radio-type devices have been all over, portable computers as well, and networking radios autonomously together made appearances. Ditto for adding a camera to standard communications devices. I’m not really sure how much of it you need going at once to consider it a smartphone.

    Like the guy in the link mentions, what people would choose to do with them and just how often was the hard thing to predict. When someone pops open a version of the internet in Heinlein it’s always to do research. It’s never cat pictures or porn or to post a random picture of themselves and what they’re doing. Usually the computer is part of your spaceship or whatever, not in your pocket, just for that reason.


  • And then there after things that nobody can even imagine today. Like nobody could imagine a smartphone thirty years ago.

    I mean, there’s people who did, going back pretty far. Just not the exact societal impact they would have. The laws of physics have been nearly complete for many decades, so don’t expect a life of true surprises like a person born in 1870 would have experienced.

    If you actually read this, OP says there’s little point going anywhere in the solar system other than Earth. There’s barren rocks right here if that’s your thing, and they even come with free oxygen, gravity and radiation shielding. The rest is about interstellar travel.



  • It’s entirely possible. Actually I suspect Elon might get to Mars and realise it sucks, because he’s nearly alone on a barren planet and Twitter has massive lag.

    After the moon, Titan is the only place here that seems worth bothering with a colony on. Hopefully we do (some variant on) sleeper ships at some point, because our sun will only last so long, but if there’s no dumb billionaires to fund it in the future we might just not bother.

    Edit: That said, I wish OP made more of a distinction between cost, feasability and present mature technology. We can feasibly live without an atmosphere, but it might not be worth the cost. We can feasibly reach a few percent of lightspeed, but not with conventional rockets. (Other technologies are mentioned in the footnotes, but OP’s grasp of the alternatives seems to be lacking. Fission-electric has working prototypes, we could theoretically make ourselves smaller or more space-hardy, magnetic parachutes to slow down…)

    I think the conclusion is justifiable, but the whole thing is a bit sophomoric.










  • Haha, I thought it was a homework question. It would be a pretty good one; it’s not hard to answer, but the a proof touches on a lot of things. I probably would have gone about this differently if I hadn’t thought I was addressing someone who’s actively studying these things. Hopefully you still knew most of the terms I was using.

    And the missing part, because including an exercise is low-key a dick move if you were just curious:

    Any basis vector k can’t be 0 (that would be dumb), so if O(k)=0 it fails idempotence and can’t be in the range. Therefore, all kernel bases are not in the range.

    For the range being a subspace, O(a+b)=O(a)+O(b)=a+b, and you can extend that to any linear combination of range vectors.

    I guess you’d need to include the proof that vector (sub)spaces must have a basis to make it airtight, so we know the kernel has any dimensional at all. But, then it’s just the pigeonhole principle, since you can choose a basis for the whole space made up from bases of the two subspaces.

    Best of luck.


  • Definitely.

    It’s a violent world. If you think you can magically opt out of that, somehow, you might have lived a massively privileged life (to this point).

    That being said, look at all the people in the thread who are afraid to admit possible abstract, hypothetical support for something. On a hard-left instance, of an alt platform, that I’m currently using over Tor. That should be an indicator of how much actual will there is to brave a shooting war. (You didn’t ask if we wanna revolution specifically, but this is .ml so I have to address it)

    The practical takeaway of the literal question is much more nuanced and subtle.



  • I would go seriously digging for the source for you, since a cursory search is full of modern stuff and I can’t remember where I saw it exactly, but that would require non-glued fingers.

    If you look at old (siege) engineering manuscripts, they’re full of “take the square root of the armslengths and rewrite as dactyls”-type rules for everything. They didn’t know much about mechanics, and often had funny ideas like momentum being self-dissipating if not sustained. but enough experimentation and basic calculating tools allows you to make rules of thumb anyway.

    And, it’s not like nobody could see how things moved through the air when launched or dropped. Basic principles about falling things go back to the 14th century at least, and the ancient Greeks thought so much about parabolas one must have at least noticed that’s the trajectory of a thrown javelin, albeit without even algebra to start to explain why.

    For example, we don’t need to know about ballistics to use a gun.

    Sure, but you need to know about the trigger and where the bullet comes out of. And, if you don’t know about the recoil, how to load it and where the casing is ejected you might not use it well.

    Thinking about places like Europe and China, there’s probably over a billion people that have never seen a gun operated in real life, so I suppose that’s actually not really necessary, either. On the other hand, I have trouble imagining a modern person who’s never needed to convey “perpendicular”.

    You can define knowledge as enablement to do things.