• 0 Posts
  • 42 Comments
Joined 7 months ago
Cake day: March 3rd, 2024
  • Nougat@fedia.iotomemes@lemmy.world•Scumbag Universe
    11·
    2 days ago

    Crude, yes. Fair, no.

    Consider a balloon. Uninflated, make a mark on opposite sides, and then make a third mark right next to one of those. When you inflate that balloon, the two points on opposite sides of it become farther apart because of the stretching of the whole balloon, but the two marks right next to each other don’t become nearly as far apart, because they are only experiencing “local” expansion.

  • Nougat@fedia.iotomemes@lemmy.world•Scumbag Universe
    15·
    2 days ago

    So all space is expanding. Locally, that’s “just a teeny tiny bit,” and the force of gravity is plenty strong enough to keep things up to about the size of galaxies (maybe galaxy clusters) gravitationally bound. Andromeda, for example, is the only galaxy that is heading towards us.

    But all of space is quite big. Over the vast distances of space, all of the “teeny tiny” local expansions add up. This means that the galaxies which are furthest away from us are also receding from us most quickly. This is not because those galaxies are moving through space; it’s because of all the expanding space in between them and us.

    The speed of light (in a vacuum) is the fastest anything can move through space.

  • Nougat@fedia.iotomemes@lemmy.world•Scumbag Universe
    18·
    2 days ago

    If we are considering “the universe” to mean the spacetime that we exist in, there could be an “outside,” but we just don’t know, and there’s no indication of such an outside, or anything about what it would be like.

    By way of infinite spacetime, yes, there is only a part of spacetime that we can observe, because the farthest part is moving away from us faster than the speed of light. I seem to recall there having been some estimations of how large all of spacetime is, observable and unobservable, and that it has a finite size.

    That said, there does not appear to be a limit to the size of spacetime. Based on what is currently known, spacetime is expanding, the expansion is accelerating, and there is no limit to the expansion.

  • Nougat@fedia.iotoTechnology@lemmy.world•Headlamp tech that doesn’t blind oncoming drivers—where is it?
    1·
    7 days ago

    That definitely plays a part, but there are other bits, too.

    Old sealed beam lamps simply weren’t as bright as halogens or LEDs (or Xenons, for that brief moment in automotive lighting history). Sealed beams didn’t throw out as pure a white light, either, and they were more likely to become badly aimed. Sealed beam reflectors were all the same, no matter what car you put them on; automakers could adjust composite headlights to have whatever beam shape they wanted. All together, you could not see as far when using sealed beams in comparison to newer bulb technologies.

    Back in the mid-1980s, when composite headlights were becoming more common on new cars, highway speeds were simply not as fast. Anecdotally, going 75MPH on the highways in and around Chicago was screaming fast in the 80s. Today, 75MPH on those same highways is slow. Modern cars are simply more capable of safely driving at high speeds, and part of that is because modern headlights are designed to throw whiter light farther. Headlights are brighter.

    Throw some supermassive trucks and SUVs into the mix, where their OEM positioned headlights are higher off the ground, and many of them have big tires or lift kits making that even worse (and where exactly zero people who lift their vehicles also reaim the headlights) - if you’re in a compact or midsize sedan, well, fuck you.