• 2 Posts
  • 93 Comments
Joined 1 year ago
cake
Cake day: June 5th, 2023

help-circle



  • If you’re actually curious, or someone else reading this is, you never can get a rocket, or anything with mass, to the speed of light either, not just faster than it, but you can get arbitrarily close. However, you never notice anything stopping you going faster than your current speed, there’s no point where your rockets stop working or anything, rather, time and space stretch and squeeze such that neither you nor anybody else see you going faster than light. If you have a magic rocket that somehow has infinite fuel and can fire forever, you can actually get anywhere as fast as you want, from your perspective.

    Alpha centauri is famously about 4 light years away, but you can get there in 2 seconds, from your perspective, if you go fast enough. But, everyone on earth will see slightly over that roughly 4 years go by in the time that for you is just 2 seconds. (You’ll see them move slowly too at first, since they’re moving relative to you just as fast as your ship is moving to them, but when you slow down, you’ll see them seem to speed up until you’ll have seen them do 4 years worth of stuff by the time you stop). Meanwhile on your ship, you don’t see yourself crossing that 4 light year distance in less than the allowed time either, because space itself is squished kinda, so that the distance to alpha centauri is shortened to the point that if you’re getting there in 2 seconds, it’s now less than 2 light seconds away, from your perspective, and you’re not moving faster than light to cross that distance in that time. People outside will also see your ship compressed like this too.

    This isn’t just a regular optical illusion either, space and time really are different for the people on and off the ship (and indeed very slightly different for everyone anywhere). Nobody has the “correct” view of the universe, because everyone’s perspective is equally valid.


  • I imagine any explanation of the expansion of the universe for people that are not themselves studying astronomy is going to be simplified in a way that gives the average person the basic idea but not the complete picture to avoid confusion when explaining the concept. Ive not studied astronomy, but I did get most of the way through a physics degree, and know that at least there, a lot ideas are explained in that sort of way to people without much knowledge of the subject, especially the more confusing concepts. I wouldnt be surprised if thats the case for most fields of science. For a different example as an analogy, its common knowledge that you cant move faster than light (ignoring the whole expanding spacetime stuff), but it isnt always explained why this is the case, leading to questions from some people like “what happens if I fly a spaceship to the speed of light, and then turn on the rockets to try to go faster?” which have easy answers or just dont make sense as a question if one has had the behavior of objects at high speed explained, but which seem reasonable enough questions to ask if all youve been told is that the speed of light is just some cosmic speed limit. People cant reasonably blame you for finding an incomplete explanation you’ve been given, well, incomplete, and then asking questions that come to mind as a result.






  • I used to be pretty excited about 3d printed homes, but an argument I’ve seen, that’s made me a lot more skeptical of them, is that much of the work of building isn’t putting up the actual walls, it’s all the wiring, plumbing, installing windows and climate control and insulation and roofing and whatever else like that that turns a building from essentially an artificial cave into a more livable space. A 3d printer that prints you walls out of concrete or whatever is only doing the easy part for you in that case, and not necessarily even in the most efficient or desirable manner. Not to say that the idea of more efficient ways to build housing cheaply isn’t interesting to me, I just think that it’d be something more boring, like a a bunch of improvement to modular prefab construction. 3d printing is an awesome technology, but it’s not a good option for everything







  • Something to consider here is that selective breeding of dogs is very often not done to the dog’s benefit, and indeed in some breeds makes them less healthy. It’s done for the benefit of their owners, either to do some job or for aesthetics, in a way that would be considered absolutely abhorrent if done to people (indeed, a lot of people think that in dogs it can go too far, especially where breeds with health problems are concerned). Eugenics is at least conceived by its proponents as being for the good of the species in a way that dog breeding is not, it’s just that the easiest way to do that is to control who has children, which isn’t generally considered acceptable for people, and the easiest ways to prevent someone you don’t want to have children from doing so are to kill or forcibly sterilize them, which is even worse. Additionally, it’s tricky to know what traits even are detrimental or beneficial to the species, and the personal biases of whoever is in charge come into play (for instance, a lot of historical examples of eugenics being pushed have been by people who were, well, extremely racist and therefore selecting for things like skin color, which if successful would simply lower genetic diversity, which is counterproductive)

    Now, as far as comparing humans to dog breeds (as in, why people find it okay to say “x breed of dog tends to be more aggressive”, but not “x group of people are more aggressive”), it should be considered that humans already have a rather low genetic diversity, as far as species go. If were we like dogs, we would probably all be the same “breed”, so to speak, even people from different ethnic backgrounds (sure, we can tell ourselves apart due to not looking exactly the same, but even two dogs of the same breed don’t look exactly alike, and we’re very attuned to seeing small differences in humans that we might not see in other animals). I’d bet it would probably be possible to eventually selectively breed a bunch of humans to have noticably and consistently different traits beyond just skin and hair color (which while visibly distinct from the outside, don’t really represent very much change), but intentionally engaging in breeding humans like dogs like this would be considered, well, a horrible thing to do, and in any case, isn’t what we currently have nowadays.


  • If you don’t want your posts/content to appear on other websites from the one you posted it on, why would you use a federated platform in the first place? Isn’t the entire point of these kinds of platforms that this kind of content is shared between sites?

    And on a mostly unrelated side note, that bit about people trying to force the website to display CP to get the owner in legal trouble is exactly the reason why strict liability crimes that don’t care about intent are a bad idea