654
The speed of light (mander.xyz)
submitted 5 months ago by to c/science_memes@mander.xyz
123 comments fedilink hide all child comments
 
you are viewing a single comment's thread
view the rest of the comments
[–] 81 points 5 months ago (19 children)

  • permalink
  • fedilink
  • source
  • hideshow 19 child comments
    •
  • [–] 206 points 5 months ago (6 children)

    When sailing boats pushed for speed they ended up hitting an unexpected speed barrier. As you increase velocity the break wave created by the bow of the ship elongates until the length of the ship is at 1 wavelength, then the hull drag prevents further acceleration. For a 50 meter ship it's about 17 knots. You can get much faster lifting the boat from the water as you gain speed with an underwater wing, the current max speed was set 47 years ago at ~276 knots. But that's only because they can remove the hull from the high drag environment and is extremely dangerous to attempt to break. The speed of light is nothing like that because spacetime itself can stretch and squish, I just wanted to talk about boats for a bit.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 6 child comments
    •
  • [–] 25 points 5 months ago (1 child)

    I'm not even mad because now I get why and how these competition multihull boats basically fly above water while keeping like 1% of the boat in water

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 1 child comment
    •
  • [–] 11 points 5 months ago

    Those ones are reaching a new speed limit as well, the cavitation around the hydrofoil starts at a certain speed/angle and stalls the foil, which then abruptly drops the hull back into the water.

    I’ve been wondering how long before the equivalent of variable swept wings will be added to the cup boats.

  • permalink
  • fedilink
  • source
  • parent
  • [–] 41 points 5 months ago* (5 children)

    You have two observers, moving directly opposite each other.

    Each has a flashlight pointing back at the other.

    The speed of the light from those torched is the same for both observers.

    (Instead the light would be red-shifted.)

    Add a third observer, stationary to one and moving towards the other. As the third observer passes that observer, the speed of light from their flashlight never changes, and it’s the same speed as from the other two. (Instead it would go from being blue shifted to red shifted.)

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 5 child comments
    •
  • [–] 48 points 5 months ago (4 children)

    This adds substantially more questions than it answers.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 4 child comments
    •
  • [–] 2 points 5 months ago

    It's complicated (and don't trust me too much, I'm not qualified), but if you've heard of time dilation and whatnot, if you start traveling at speeds comparable to the speed of light, spacetime distorts in such a way that from your point of view all light coming from any direction travels at the same speed.

    This is also why (or one of the reasons) according to science you cannot travel faster than the speed of light, since light would still need to be traveling away from you at the speed of light and you'd need to occupy negative space in that direction, or something like that.

  • permalink
  • fedilink
  • source
  • parent
  • [–] -2 points 5 months ago

    Different phases (colours of light) move at different speed, and have different longevity, I think. So how they always thought those pretty galaxy nebula photos, were red? Actually turns out that phase of light just travels for a longer time. Lasts longer. OK, now someone correct me, because I have absolutely no idea what I'm talking about. Just bring up vague floating memories from an article i read once.

  • permalink
  • fedilink
  • source
  • parent
  • [–] 4 points 5 months ago (4 children)

    The fact that this gif has a brief pause between the "ex" and the "explain" really irks me

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 4 child comments
    •
  • [–] 5 points 5 months ago (2 children)

    It’s there to convey the line’s intonation.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 1 point 5 months ago

    The simplest explanation I know: Nothing can travel faster than the speed of light. If you ever end up with something that makes the speed of light change, it's actually time that changes.

  • permalink
  • fedilink
  • source
  • parent