4 ms·

Yes, but when you drop something, you're creating a reference frame, aren't you?

by buo 13y ago

shardling 13y ago
Ah, you're misunderstanding the term reference frame as it's being used here. A reference frame is like a coordinate system for velocity; it's not something physical.
ars 13y ago
No. When you drop something nothing whatsoever happens. And as shardling said, a reference frame isn't a physical thing that is created and destroyed - it's simply the zero point for your system of measurement - but the measurement would work just fine if you started with any number, zero is just convenient.
- buo 13y ago
  I understand a frame of reference doesn't have to be physical. However, if you're in an apparently empty and dark universe, and you're interested in knowing whether you're accelerating or not, postulating a frame of reference is not going to be of much help. I may have missed the point of dropping an object, though. I thought the idea was to create a physical point we could anchor the coordinate system to, and in that way be able to measure acceleration.
  - ars 13y ago
    > However, if you're in an apparently empty and dark universe, and you're interested in knowing whether you're accelerating or not You can't. There is absolutely no test that can tell you this. You can't "drop" anything - whatever force is accelerating you also accelerates the object, so letting go of it tells you nothing.
  - Dylan16807 13y ago
    Dropping an object that won't get accelerated is one way to measure acceleration, but not the only way. If you are the actor causing the acceleration on yourself, as I originally intended, then presumably you already know / measure-by-doing how much you have accelerated, and you can use dead reckoning to watch the earlier reference frame fly by. If the force is external and doesn't apply pressure then you have to drop an object. If the force affects the entire universe the same way then that's aether and can't be measured / doesn't exist. But that was not the kind of force I was using to disprove "you can't move".
    - ars 13y ago
      > If the force is external and doesn't apply pressure then you have to drop an object. What kind of force is external and doesn't apply pressure, and also doesn't affect the dropped object? There is no such force, and therefor no such test.

Yes, but when you drop something, you're creating a reference frame, aren't you?

by buo 13y ago

Yes, but when you drop something, you're creating a reference frame, aren't you?

Ah, you're misunderstanding the term reference frame as it's being used here. A reference frame is like a coordinate system for velocity; it's not something physical.

ars 13y ago

No. When you drop something nothing whatsoever happens. And as shardling said, a reference frame isn't a physical thing that is created and destroyed - it's simply the zero point for your system of measurement - but the measurement would work just fine if you started with any number, zero is just convenient.

buo 13y ago
I understand a frame of reference doesn't have to be physical. However, if you're in an apparently empty and dark universe, and you're interested in knowing whether you're accelerating or not, postulating a frame of reference is not going to be of much help. I may have missed the point of dropping an object, though. I thought the idea was to create a physical point we could anchor the coordinate system to, and in that way be able to measure acceleration.
- ars 13y ago
  > However, if you're in an apparently empty and dark universe, and you're interested in knowing whether you're accelerating or not You can't. There is absolutely no test that can tell you this. You can't "drop" anything - whatever force is accelerating you also accelerates the object, so letting go of it tells you nothing.
- Dylan16807 13y ago
  Dropping an object that won't get accelerated is one way to measure acceleration, but not the only way. If you are the actor causing the acceleration on yourself, as I originally intended, then presumably you already know / measure-by-doing how much you have accelerated, and you can use dead reckoning to watch the earlier reference frame fly by. If the force is external and doesn't apply pressure then you have to drop an object. If the force affects the entire universe the same way then that's aether and can't be measured / doesn't exist. But that was not the kind of force I was using to disprove "you can't move".
  - ars 13y ago
    > If the force is external and doesn't apply pressure then you have to drop an object. What kind of force is external and doesn't apply pressure, and also doesn't affect the dropped object? There is no such force, and therefor no such test.