3 ms·

Yeah, if every part of human body is accelerated equally, there's no way to feel anything (you could see it). No matter how hard you get hit or thrown around, y

by Geee 3y ago

Yeah, if every part of human body is accelerated equally, there's no way to feel anything (you could see it). No matter how hard you get hit or thrown around, you can't measure it internally. Each cell can only feel their neighbors, and there's no internal stress / force between cells.

saagarjha 3y ago
This isn’t true. Try jumping off a building and you’ll find the acceleration to be quite noticeable ;)
- stetrain 3y ago
  Only because you feel the air rushing past, and the impact with the ground. If you do this in a capsule where the air is moving with you, and avoid hitting the ground, we call the sensation "weightlessness" or "zero g", like is experienced by astronauts in orbit. Gravity is absolutely acting on astronauts orbiting the earth, at nearly the same strength as if they were standing on the ground. Depending on the shape of the orbit their linear speed may be increasing or decreasing, and they are definitely experiencing directional acceleration as their path bends in a circle around the Earth. But internally there is no bodily sensation of acceleration. It feels the same as floating, or free fall without the air rushing past.
  - saagarjha 3y ago
    Yes but the feeling of weightlessness is something you can distinguish!
    - stetrain 3y ago
      But you don't feel the force of acceleration. Floating weightless and motionless in space feels the same as being in an elliptical orbit around a planet.
      - lupire 3y ago
        Even more, accelerating due to a being in an (idealized) rocket also feels the same. https://www.npl.washington.edu/eotwash/equivalence-principle https://www.npl.washington.edu/eotwash/equivalence-principle This has to be true, because if you can't (internally) detect the difference between nothing and a planet being nearby, you obviously also can't detect how massive the planet is, so you can't know if your acceleration relative to the nearby environment is due to gravity or something else, or even how much "absolutel" acceleration you have. Standing on earth (or the floor of your rocket) feels different due to electromagnetic effects of the nearby "touching" external objects.
  - ivell 3y ago
    I did sky diving some years back. I did feel acceleration immediately after the jump for a second, but then afterwards it was as if I was lying on bed. So what was that feeling I experienced (it was similar to maintain giant wheel coming down)
    - stetrain 3y ago
      Going from standing on a surface where you are resisting the force of gravity (like standing on the ground, or in a stable aircraft) to being in free fall definitely has a sensation. It's a sensation that actually causes a decent percentage of people to feel physically ill for a period after launching to orbit on a rocket. It's like going over the top of a hill on a roller coaster where you go from being pulled down into your seat to floating up against the restraints. But once you're falling, or or in orbit (which is also free fall just outside an atmosphere), you don't feel the changes in velocity (acceleration) due to gravity.
- neolefty 3y ago
  The point is you won't feel it (aside from air resistance) on the way down.
  - 8note 3y ago
    The air too, you only feel because the ground and other air is pushing it upwards
- Geee 3y ago
  If the impact somehow could stop your all cells at the same rate, you wouldn't feel it. Your body gets compressed because of different rates of acceleration. If aliens have tech which can apply this type of force field / acceleration, then they won't get squished in their spaceships no matter how hard they accelerate. You basically need a large force field like gravity, instead of transferring force via small intermolecular force fields.

by Geee 3y ago

saagarjha 3y ago

This isn’t true. Try jumping off a building and you’ll find the acceleration to be quite noticeable ;)

stetrain 3y ago
Only because you feel the air rushing past, and the impact with the ground. If you do this in a capsule where the air is moving with you, and avoid hitting the ground, we call the sensation "weightlessness" or "zero g", like is experienced by astronauts in orbit. Gravity is absolutely acting on astronauts orbiting the earth, at nearly the same strength as if they were standing on the ground. Depending on the shape of the orbit their linear speed may be increasing or decreasing, and they are definitely experiencing directional acceleration as their path bends in a circle around the Earth. But internally there is no bodily sensation of acceleration. It feels the same as floating, or free fall without the air rushing past.
- saagarjha 3y ago
  Yes but the feeling of weightlessness is something you can distinguish!
  - stetrain 3y ago
    But you don't feel the force of acceleration. Floating weightless and motionless in space feels the same as being in an elliptical orbit around a planet.
    - lupire 3y ago
      Even more, accelerating due to a being in an (idealized) rocket also feels the same. https://www.npl.washington.edu/eotwash/equivalence-principle https://www.npl.washington.edu/eotwash/equivalence-principle This has to be true, because if you can't (internally) detect the difference between nothing and a planet being nearby, you obviously also can't detect how massive the planet is, so you can't know if your acceleration relative to the nearby environment is due to gravity or something else, or even how much "absolutel" acceleration you have. Standing on earth (or the floor of your rocket) feels different due to electromagnetic effects of the nearby "touching" external objects.
- ivell 3y ago
  I did sky diving some years back. I did feel acceleration immediately after the jump for a second, but then afterwards it was as if I was lying on bed. So what was that feeling I experienced (it was similar to maintain giant wheel coming down)
  - stetrain 3y ago
    Going from standing on a surface where you are resisting the force of gravity (like standing on the ground, or in a stable aircraft) to being in free fall definitely has a sensation. It's a sensation that actually causes a decent percentage of people to feel physically ill for a period after launching to orbit on a rocket. It's like going over the top of a hill on a roller coaster where you go from being pulled down into your seat to floating up against the restraints. But once you're falling, or or in orbit (which is also free fall just outside an atmosphere), you don't feel the changes in velocity (acceleration) due to gravity.
neolefty 3y ago
The point is you won't feel it (aside from air resistance) on the way down.
- 8note 3y ago
  The air too, you only feel because the ground and other air is pushing it upwards
Geee 3y ago
If the impact somehow could stop your all cells at the same rate, you wouldn't feel it. Your body gets compressed because of different rates of acceleration. If aliens have tech which can apply this type of force field / acceleration, then they won't get squished in their spaceships no matter how hard they accelerate. You basically need a large force field like gravity, instead of transferring force via small intermolecular force fields.