Mad Question that just ocurred to me

[max-greece]

I think you would also have to assume a commensurate uniform decrease in mass; otherwise, relativity wouldn't work. Would also imply that the speed of light is not constant.

The speed of light is constant relative to the universe - whether that is shrinking or growing in "real terms" but I think I might have an answer as to why this must be the case but I am seriously confusing myself:

If we assume energy is constant (safe?) and E=mc^2 then if c is getting smaller in "real" terms m must be getting bigger to balance the equation, surely?

On the other hand if we look at Neuton's gravitational equation:

F = G(m1+m2)/r^2

If the "real" distance is shrinking and the masses increasing then unless the force is getting larger G cannot be constant.

I think? My brain exploded about 20 minutes ago.

[Cato]

Would also imply that the speed of light is not constant.

From a certain perspective, yes. The meter is definitially the distance light travels in (mumble) fraction of a second. The OP said the meter is becoming smaller which seems to imply that light would still travel between point A and B in the same amount of time. This is the point where I decided to get back to my nap.

If the absolute distance decreases despite the fact we still call it a meter, transit time would also have to decrease to keep speed constant.

[max-greece]

Guys,

Just to add a few points:

1. I am not saying this is how it is - I am asking how we might know.
2. I don't want this to be true any more than I want it not to be true.
3. The God example is only there to ensure we are all on the same page with what I am asking - I no more believe that than I believe fairies control gravity.
4. The point is not the "trick" the point is why would a shrinking content universe be any less likely than an expanding universe - other than it being hard for us to understand.
5. I might have solved the issue anyway with the above - but I am not sure.

[Cato]

I get it and think we're all considering it the same. If distance is decreasing AND we still assume our discovered natural laws to be true then all associated measured properties must also change. I think this leads us to a situation where discovery would remain out of reach.

[vorlon13]

If the universe (as we know it) is in a much larger (infinite) expanse of 'nothing' a net change in the size of the universe over and above what we see, if 'scaled' proportionally to all forms of matter, fields, energy(s) etc. is irrelevant and unknowable.

Kinda like the holy ghost, only more scientifical.

[Angrboda]

I don't know the physics well enough, but I think the four fundamental forces, strong, weak, electromagnetic and gravitational, they vary differently over different distances. The "size" of an object is dependent on the strengths of these forces and how they behave. If everything were getting smaller, one or more of these forces would have to be decreasing, but if the relationships with respect to distance were not linearly related, there would be an inconsistency in how one or more of the forces varied, making the change detectable. This is more guess than something I know, but it sounds right. Under quantum mechanics, one of these relationships would diverge from the expected value, I think....

[max-greece]

If the universe (as we know it) is in a much larger (infinite) expanse of 'nothing' a net change in the size of the universe over and above what we see, if 'scaled' proportionally to all forms of matter, fields, energy(s) etc. is irrelevant and unknowable.

Kinda like the holy ghost, only more scientifical.

Fine - but is it less likely than the assumed state?

I don't know what it would change, if anything, in physics, but I have never heard anyone even propose such a thing and I have to wonder why it isn't mentioned as a possiblity.

Whilst it is a harder to understand approach within the universe it does make the idea of the multiverse easier to get to grips with.

[vorlon13]

A 'change' scaled proportionally to 'everything' is irrelevant. If the 'speed of time' varies erratically, or oscillates between positive and negative values, again, it don't matter as presumably, everything would 'rewind' and 'fastforward' perfectly, so we would be unaware.

[max-greece]

I don't know the physics well enough, but I think the four fundamental forces, strong, weak, electromagnetic and gravitational, they vary differently over different distances. The "size" of an object is dependent on the strengths of these forces and how they behave. If everything were getting smaller, one or more of these forces would have to be decreasing, but if the relationships with respect to distance were not linearly related, there would be an inconsistency in how one or more of the forces varied, making the change detectable. This is more guess than something I know, but it sounds right. Under quantum mechanics, one of these relationships would diverge from the expected value, I think....

I was thinking much the same thing but with regards to the constants of the universe (gravitational, universal, plank and so on). If one of those would have to vary for my question to be possible then it rules out the possibility - if you know what I mean.

[Cyberman]

This is the point where I decided to get back to my nap.

I knew those rumours about you and Nap were true!