# How is it Moving?

screwball
ok say i have a rock sitting on my desk next to my computer. what are all the different ways it is moving? universaly*

i think about it a lot and a previous post gave me the idea to ask all of you. Would love to hear different perspectives

Homework Helper
It can move any way you want if you choose the right reference system. How is it moving relative to what?

Gold Member
Well, yea...as the Earth is rotating is moving that way...as the Earth is going around the sun its going that way...as the solar system is moving around the galaxy, its moving that way...as the galaxy is moving in space, its moving that way...

But again, reference points...if ure sitting next to it, its not moving at all, which is as valid as if someone was flying by our solar system and saw the rock moving, but then u see the rock standing still and the person moving..yeah...*confuzzled*

yes, you can't answer this question without allocating a reference frame. Its an impossible question, because ultimate motion is governed by the boundaries of the universe. Can you invisage that?

I think not...

screwball
yeh thanks

forgetit

Artman
Or is that rock standing still and all other motion is happening around it?

If you have ever looked through a telescope at low power, say 10x, you can walk away from it for five minutes, return and it is still pretty much the same view as when you left, but raise the magnification to 150x and suddenly that star or planet that was centered a second ago is marching toward the side of the field of view and out of sight. Although the stars and other planets are moving relative to us, the motion we percieve as the stars moving is mainly the rotation of the Earth underneath of the telescope.

I believe this should go into the philosophy forum because if you are asking how it is moving, then that suggests you are the observer, and since you are there looking at it, in the same general reference frame, the rock is not moving whatsoever, unless a force is applied on it within your reference frame.

Rock is actually moving up (with acceleration about 9.8 m/s^2).

This is quite easy to detect by any accelerometer (like a mass on spring, or mass on a string - a pendulum, etc).

jackle
The rock is moving internally at a molecular level, with a random kinetic energy related to it's heat

And each proton/neutron/electron in it is likely just a motion of sub-stuff (vacuum? massless string? space-time?) in it, creating illusion of mass and of other quantities (charge, spin, etc). In reality there may be nothing "physical" in there.

Originally posted by Alexander
In reality there may be nothing "physical" in there.
...which is why this is a philosophical topic more than it is physics..

I would rather say "mathematical" instead of "philosophical".

anil
What is really moving?

If you don't see it moving, then it's not moving. Well it's exerting a force on an object (table) and table is exerting a force back of same magnitude. It is rvolving with the earth. If Earth is frame of reference the rocks not moving but a force acts on t every single instant (it's weight). It depends on your frme of reference. If your frame of reference is let's say planet jupitur...then it's moving.

wuliheron
Originally posted by screwball
ok say i have a rock sitting on my desk next to my computer. what are all the different ways it is moving? universaly*

i think about it a lot and a previous post gave me the idea to ask all of you. Would love to hear different perspectives

It has obviously moved you...

Is motion real or unreal? Local or nonlocal? Why care?

Quiet

Great perfection can seem incomplete,
But does not decay;
Great abundance can seem empty,
But does not fail.