## Absolute rest is impossible - All is motion

• 1.3k
My point wasn’t that an object at absolute rest can exist, but that the concept exists only as a possibility. We can describe it, talk about it, perhaps even cause an object to approach absolute rest - as much as one can approach infinity. But whatever information we acquire is irrelevant.

I agree with you that ‘all objects are in relative motion’. More than that:

The world is not a collection of things, it is a collection of events. The difference between things and events is that things persist in time; events have a limited duration. — Carlo Rovelli, ‘The Order of Time’
• 7.1k
You all deny/critique that <all objects are in relative motion>

If you all are right then there is must be an object at absolute rest.

Can you prove that?

There is no need to prove that. The person who claims that all motion is relative needs to prove that there is no such object as absolute rest. Until it is proven that all motion is relative, the critique of this premise is justified.
• 5.8k
:up: :clap:

There is no need to prove that. The person who claims that all motion is relative needs to prove that there is no such object as absolute rest. Until it is proven that all motion is relative, the critique of this premise is justified.

There is a need to prove that there exists an object in absolute rest because there are only two contradictory possibilites:

1. An object in absolute rest

or

2. Everything in relative motion

Since you're denying 2 then 1 must be the case. So, prove it.

Let's try again...

Suppose there is an object, A, in absolute rest i.e. at rest relative to everything else.

But we know that there exists at least 2 objects in relative motion of the displacement kind i.e. the distance between them change e.g. a car moving towards you.

Is it then possible that A is at rest (absolute) relative to both the car and you??

There are three points: object A, the car (B) and you (C) forming a triangle.

We know that the distance BC is changing. Can the distance AC and AB remain constant i.e. can A be at rest relative to both B and C?

I think it's impossible. The pythagorean theorem proves it.
• 7.8k
Ok. So don't come to this forum for help with your physics assignments.

Bloody hell. What a mash.
• 5.8k
Ok. So don't come to this forum for help with your physics assignments.

Bloody hell. What a mash.

:chin:
• 7.1k
There is a need to prove that there exists an object in absolute rest because there are only two contradictory possibilites:

1. An object in absolute rest

or

2. Everything in relative motion

Since you're denying 2 then 1 must be the case. So, prove it.

I was not denying 2, I was critical of anyone who would say that absolute rest is impossible, without first defining what "absolute rest" means. Now you have made progress toward a definition, saying absolute rest involves an "object" at absolute rest. Since I consider "absolute rest" to be an ideal, I don't agree with this requirement, unless an ideal is an object. Are you saying that an ideal, like "absolute rest", is an object? If so, in what way is it an object?

Let's try again...

Suppose there is an object, A, in absolute rest i.e. at rest relative to everything else.

But we know that there exists at least 2 objects in relative motion of the displacement kind i.e. the distance between them change e.g. a car moving towards you.

Is it then possible that A is at rest (absolute) relative to both the car and you??

There are three points: object A, the car (B) and you (C) forming a triangle.

We know that the distance BC is changing. Can the distance AC and AB remain constant i.e. can A be at rest relative to both B and C?

I think it's impossible. The pythagorean theorem proves it.

You ought to see that this is nonsense. "Absolute rest" would be the standard by which all motions are measured. Therefore everything would be in motion relative to "object A" (absolute rest), unless there was something else which was at absolute rest. Only things at absolute rest would be unchanging relative to absolute rest, everything else would be changing relative to absolute rest.
• 41
Newton stated an object at rest and an object in motion remain in that state unless acted on by a force.
Position of an object is relative to a reference object.
Motion is a change in position, thus relative to a ref. object.
Speed is the rate of change of motion, which has a range of 0 to light speed c.
We measure motion to determine rest, which is the absence of motion, just as dark is the absence of light, and dry is the absence of moisture. Thus there is no um for rest, and rest is also a relative state.
Newton defined two states of motion.
Let's redefine rest as the special case of two objects that have the same velocity.
Each object is at rest relative to the other, while simultaneously being in motion.
• 5.8k
You ought to see that this is nonsense. "Absolute rest" would be the standard by which all motions are measured. Therefore everything would be in motion relative to "object A" (absolute rest), unless there was something else which was at absolute rest. Only things at absolute rest would be unchanging relative to absolute rest, everything else would be changing relative to absolute rest.

I must humbly disagree. Can you prove that, to quote, "there is(was) something else which was at absolute rest"?
• 7.1k

Do you see the word "unless"? Suppose an object is assumed to be at absolute rest. All other objects would be in motion relative to this object "unless there is something else which was at absolute rest". To have an object which is not moving relative to the object which is at absolute rest requires that this object is also at absolute rest.

Therefore the fact that all objects are moving relative to another object does not negate the possibility that this other object is at absolute rest.
• 41
If position is relative to an object, then so is motion.
• 5
its a sound arguement namely because youre right!

Motion gives rise to particles, without it there are no charges to piece together constituence.

meaning you win the arguement of the year. This is iomportant moreso a thesis should be written on it.
• 366
I think there is the possibility of an object at absolute rest, but not within the contraints of this universe.

Therefore, I confer, if there is an object at absolute rest, it must be external to the universe.

Thus, all is not motion, but everything in the universe, is always moving.

The great ebb and flow of everything, hides sleightly the fact I'm never still - maddening actually.

EDIT: unless this object at absolute rest probes the universe, then it might be internal.
• 7.8k
What the fuck? Do some physics, you lot.
• 849
This was a reply to me 5 months ago and I never saw it.

What if we assume, in fact it's true that the distance between the earth and the sun keeps changing, that it's the distance AB keeps changing. Doesn't this mean AC and BC should also change?
You mean the Earth and sun are A and B respectively? The distance between them does change all the time, but not a whole lot. You didn't define what C was. If it's Jupiter for instance, then AC and BC are going to be changing regardless of the stability of AB or not. If its my mailbox, then AC is pretty constant despite the continuous change to AB.

I used the math tool geogebra and what I saw was (taking three vertices of a triangle ABC) if we move B relative to A then even if AC doesn't change BC does change.
Well its pretty easy to make a counterexample of that. Just make AC and BC hinged rods holding those points at a constant separation. AB is free to change (B moving relative to A) without changing the lengths BC or AC. It just changes the angles at each of the 3 vertices.

The mathematical proof would likely use the pythagorean theorem.
The existence of the counterexample is proof that it isn't the case.

Suppose there is an object, A, in absolute rest i.e. at rest relative to everything else.
Oh, you think absolute rest means that either 1) everything is at rest, or 2) the distance between the one resting object and every other object remains the same.
In fact, the wording (the i.e. part) is a total contradiction. Motion is either absolute or relative, so if it is at absolute rest (assuming it is even meaningful to be objectively at rest), it just means it is stationary, which has nothing to do with what other objects are doing.
At rest relative to everything else is physically impossible since there are objects too far away to have the same velocity as any object here.
• 5.8k
In fact, the wording (the i.e. part) is a total contradiction.

Correct. Thanks for pointing that out. Motion is always relative. What I meant to ask was if there exists an object that's at rest relative to everything else in the universe? There is no such thing, right?

Imagine two objects, my friend and I, moving towards each other. We're in relative motion. Now every other object in the universe must be at rest relative to either me or my friend but never both because if an object is at rest relative to me then it is in motion relative to my friend and if it's at rest relative to my friend then it's in motion relative to me. Ergo, just the existence of two objects in relative motion, every other object in the universe must also be in relative motion to one or both these objects. We have two such objects - the sun and the earth. No object in the universe is at rest relative to the rest of the objects in the universe.
• 849
Correct. Thanks for pointing that out. Motion is always relative. What I meant to ask was if there exists an object that's at rest relative to everything else in the universe? There is no such thing, right?
If there are only two objects in the universe moving relative to each other, a third object might be stationary relative to one of them, but it would be moving relative to the other at the same velocity as the thing relative to which it is stationary. This is pretty trivial geometry. Yes, you describe this in your lower paragraph.

Another way of wording it: For an object to be a rest relative to the rest of the universe, everything in the universe would need to become stationary relative to the one thing. All motion everywhere would need to stop. That's not going to happen.

In some of your posts you talk about the distance between things changing or not. That's not the same as relative motion. Given two objects in relative motion (like a pair of masses A, B in eccentric orbit say), one can find a 3rd point (not stationary) that is always some unchanging distance from them, forming a constant length AC and BC despite the ever changing AB. That's still relative motion, but unchanging separation. It might even work for 3 objects, but not 4.
• 5.8k

What about light? No matter who the observer, where the observer, relative velocity with light is always 186,000 mph. Isn't this kinda like saying that all object in the universe, because they're moving at the same velocity with respect to light, are at rest relative to each other?

I mean if a given number of things (all objects in the universe) have the same relative velocity with respect to one object (light) (light c = 186,000 mph), then these objects must be at rest relative to each other.

To illustrate, imagine objects A and B moving at the same relative velocity with respect to another object C. It follows that A and B are at rest relative to each other.
• 849
What about light? No matter who the observer, where the observer, relative velocity with light is always 186,000 mph.
The speed (not velocity) of light is constant. Each photon has a different frame dependent velocity.

Isn't this kinda like saying that all object in the universe, because they're moving at the same velocity with respect to light,
Light does not define a valid reference frame, so no, it's not like saying that. If one was to attempt consideration of such a frame, the universe collapses into a singularity and there is no space or time in which to define motion at all.

I am wondering what any of this has to do with the topic title. Absolute rest (of a given object) is conceptually possible, and it means that the object's absolute location is unchanging, and has nothing to do with what any of the other objects are doing. It requires a definition of absolute location, which isn't trivial.
• 5.8k
The speed (not velocity) of light is constant. Each photon has a different frame dependent velocity.

Isn't this kinda like saying that all object in the universe, because they're moving at the same velocity with respect to light,
Light does not define a valid reference frame, so no, it's not like saying that. If one was to attempt consideration of such a frame, the universe collapses into a singularity and there is no space or time in which to define motion at all.

I am wondering what any of this has to do with the topic title. Absolute rest (of a given object) is conceptually possible, and it means that the object's absolute location is unchanging, and has nothing to do with what any of the other objects are doing. It requires a definition of absolute location, which isn't trivial.

Just a thought and the connection to the topic title is the possibility of an object/objects that could be at rest relative to everything else in the universe.

Are you sure about what you said? I mean my reasoning appears sound (to me). If two objects A and B have the same velocity relative to another object C, then the two objects A and B must be at rest relative to each other. There's absolutely nothing wrong with the line of reasoning is there?

If that's the case then since all objects in the universe have the same velocity relative to light then all objects in the universe has to be at rest relative to each other.

Sorry for the repetition but I didn't quite comprehend your answer to my question.
• 849
Just a thought and the connection to the topic title is the possibility of an object/objects that could be at rest relative to everything else in the universe.
Not possible. Beyond a certain distance away, the Hubble expansion prevents any object from being stationary relative to something over here.

If two objects A and B have the same velocity relative to another object C, then the two objects A and B must be at rest relative to each other.
Seems correct to me.

If that's the case then since all objects in the universe have the same velocity relative to light
They do not. Read what I said above about light not defining a valid reference frame. Also, light doesn't all have the same velocity since it is moving in all different directions
• 5.8k
:up: :ok: Thank you
• 29
Absolute rest is impossible - All is motion.

The visible universe is a distortion of what is rest. Visibility is vibration of energy. All what we can detect with our own vibrant parts will also be vibration. In other words, we cannot rely on our senses, thoughts and feelings to know what rest is. In physics, as we know it, rest/death is no vibration.

What if consciousness exists without vibration, without time and space, but simply 'now' for eternity. Would that not be rest?
• 7.8k
What crap.
• 3.6k
An object at rest is just not moving with respect to its surroundings. That is, its relative velocity to its surroundings would be zero.

An object at absolute rest, maybe, is then just not moving with respect to all possible surroundings. This means its relative velocity to all possible surroundings would be zero. Unfortunately, that would mean that the surroundings couldn't move either, as that would make the relative velocity of the object to its surroundings nonzero. (Or, they'd only be able to move in ways that did not make the object contained within them move with respect to any other surroundings. Motion with nothing going by anything.)

So if there's such a thing as "absolute rest", it would have to apply to everything (or be incoherent). That is, there'd be no motion. There is motion, so there's no such thing as absolute rest.
• 5.1k
You can just declare a thing to be stationary, the earth for instance. All other motion is relative to the earth.

The "absolute" part is meant to take it out of our hands: make it something we discover rather than declare (so changing our minds doesn't alter the situation).

The earth is in free fall. It's not moving in a straight line because the space around the sun is curved.

I just evoked absolute rest: a thing that never moves. X-Y axis. Does it exist?
• 3.6k
The "absolute" part is meant to take it out of our hands: make it something we discover rather than declare (so changing our minds doesn't alter the situation).

Relative velocity isn't just "declared".

I just evoked absolute rest: a thing that never moves. X-Y axis. Does it exist?

Probably not. But I don't really know what you mean.
• 74
I think space itself is moving, in all directions. Matter is made out of and connected to space. So no thing can be motionless because matter is motion in action. Also if space expands evenly throughout the universe, even two objects which appear to be motionless relative to one another, ain't quite.

Also, what difference does it make either way?
• 5.1k
Relative velocity isn't just "declared".

A thing is stationary if we declare it be.
• 3.6k

Ok. A is walking away from B. Find a coordinate system in which they are both stationary.
• 5.1k
Why? My point was that what's meant by "absolute" is that it's mind-independent or some such. Independent of any human's choice.

It's just about ontological anti-realism. Don't declare a thing to be unreal if you can't do without it. A coordinate system is itself unchanging and apparently discovered instead a product of fiat.

Never mind.
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