Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: flr on 10/10/2013 08:10:45

Title: inertia principle in what kind of empty space?
Post by: flr on 10/10/2013 08:10:45

An object can maintain its constant velocity with no outside intervention needed.
That happens, of course, if all friction is removed.

In empty space there is no friction.
My question is: How empty this "empty space" must be such that no friction acts on moving [at constant rate] object and therefore an object can maintain its constant speed with no outside intervention ? 
I guess It must contain no particles, and no electromagnetic radiation of any kind. That means it must be devoid even of the cosmic background radiation.

Let's assume that it is possible to create an area of space that contain no particles and no photons. Not sure we can remove all photons but for argument' sake lets assume we somehow remove them all.
Is it there anything in this space (free of any particles or even photons) to slow me down (due to friction)?

One may argue that the above vacuum (with no particles or photons in it) it is still something made of "quantum vacuum".

Then my question is: as I move at constant rate will the quantum vacuum slow me down (due to friction)?   

Title: Re: inertia principle in what kind of empty space?
Post by: Pmb on 11/10/2013 04:30:24

Quote from: flr on 10/10/2013 08:10:45

An object can maintain its constant velocity with no outside intervention needed.
That happens, of course, if all friction is removed.

In empty space there is no friction.
My question is: How empty this "empty space" must be such that no friction acts on moving [at constant rate] object and therefore an object can maintain its constant speed with no outside intervention ? 

It must be absolute since you’re asking for absolute constant speed forever. Such space does not exist in reality. After that it becomes a question of how much you're slowing down.

Title: Re: inertia principle in what kind of empty space?
Post by: flr on 11/10/2013 05:57:17

So quantum fluctuations of empty space will actually slow me down, right?

Title: Re: inertia principle in what kind of empty space?
Post by: flr on 11/10/2013 06:00:05

In other words, it is not true that quantum vacuum has the property to propagate the constant velocity motion with no outside intervention to maintain it.

Title: Re: inertia principle in what kind of empty space?
Post by: Pmb on 11/10/2013 08:09:46

Quote from: flr on 11/10/2013 05:57:17

So quantum fluctuations of empty space will actually slow me down, right?

No. The bias in the 3k background radiation as well as the overall matter density in space will. At least it will until you obtain the same speed as that frame wherein you will retain constant speed.

Title: Re: inertia principle in what kind of empty space?
Post by: flr on 11/10/2013 18:21:15

Quote from: Pmb on 11/10/2013 08:09:46

The bias in the 3k background radiation as well as the overall matter density in space will. At least it will until you obtain the same speed as that frame wherein you will retain constant speed.

Let's imagine we remove all photons, even this 3k radiation as well. Then what is left? The true quantum vacuum?
Whatever is left after removing all photons and even the 3K background radiation, will still slow me down?

Title: Re: inertia principle in what kind of empty space?
Post by: Pmb on 11/10/2013 22:55:32

Quote from: flr

Let's imagine we remove all photons, even this 3k radiation as well. Then what is left? The true quantum vacuum?

Yes.

Quote from: flr

Whatever is left after removing all photons and even the 3K background radiation, will still slow me down?

If you remove interstellar dust then nothing.