Mad Question that just ocurred to me

[max-greece]

Not even sure I can express this properly. Here goes:

The universe is expanding. It is expanding at an ever increasing rate.

Suppose it isn't. Suppose everything within the universe is actually getting smaller so 1 metre 5 billion years ago was much larger than it is today (relative to some point outside the universe that is - within the universe it would appear constant).

Question - how would we know? Rather, how could we tell the difference?

[Napoléon]

Mindblowing.

[The Grand Nudger]

-we wouldn't, we couldn't

?
(I'm assuming you mean to express a situation in which "locally" we observe expansion -locally being the universe we see....but that universe being nested in some other "call it a space" that is contracting at a rate fast enough to nullify and exceed the locally observed phenomena if measured "globally" - without any other observed effects at present?)

[Jackalope]

I was thinking you'd be able to tell from spectral analysis of redshift, but the way you've worded the question seems to imply that this might not be the case.

[max-greece]

-we wouldn't, we couldn't

?
(I'm assuming you mean to express a situation in which "locally" we observe expansion -locally being the universe we see....but that universe being nested in some other "call it a space" that is contracting at a rate fast enough to nullify and exceed the locally observed phenomena if measured "globally" - without any other observed effects at present?)

I didn't fully understand your assumption but maybe this is what I mean a bit clearer.

Just for ease I am gong to assume a creator God as it helps the picture (its not really part of the answer).

So you have God who decided to make the universe on his desk. It starts as this highly energetic point and expands out from there. At some point God thinks - fuck me - this is taking over the whole desk - so he freezes it and then, in order to create the illusion of expansion within the universe - he makes everything within the universe shrink relative to him. So the universe is of fixed size in this story (although it could be shrinking itself - as long as it is shrinking at a slower rate than everything within it is) but it appears to be expanding from our POV.

The question is - how do we know it isn't?
The next question is - if we don't know why are we assuming this is not the case?
And the final point is - doesn't this solve the problem of what the universe is expanding into?

---

I was thinking you'd be able to tell from spectral analysis of redshirt, but the way you've worded the question seems to imply that this might not be the case.

It would depend on the temperature you washed the redshirt at I think.

Redshift perhaps?



Photons are getting smaller too, and light speed is relative to the universe.

I don't think it works - but keep at it because I really want to know the answer.

[Jackalope]

Damned autocorrect, we hates it precious.

[Cato]

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 Grand Nudger]

I didn't fully understand your assumption but maybe this is what I mean a bit clearer.

Just for ease I am gong to assume a creator God as it helps the picture (its not really part of the answer).

So you have God who decided to make the universe on his desk. It starts as this highly energetic point and expands out from there. At some point God thinks - fuck me - this is taking over the whole desk - so he freezes it and then, in order to create the illusion of expansion within the universe - he makes everything within the universe shrink relative to him. So the universe is of fixed size in this story (although it could be shrinking itself - as long as it is shrinking at a slower rate than everything within it is) but it appears to be expanding from our POV.

The question is - how do we know it isn't?

With the added encumbrance of a sentient trickster that is capable of such thorough deception - how do we know anything? (the trickster need not even be sentient, obviously..it's the trick thats important).

The next question is - if we don't know why are we assuming this is not the case?

We're not simply assuming, we can only work from what we know. We can only make solid conclusions with a firm actionable foundation of knowledge/observation.

Since your proposal eliminates any way of knowing this (or anything..really)specifically by the way you've worded it........

I see this alot though, when we go about explaing things in this way we're not assuming that we're right, just stating that this is as far as we know from what we can tell. Provisional certitude. If we wanted to just assume things we wouldn't have to be so pedestrian with regards to those assumptions.

And the final point is - doesn't this solve the problem of what the universe is expanding into?

Hehehehehe, I suppose it does, in a roundabout way. What with solving problems of knowledge by eliminating the possibility of knowledge.....

[Jackalope]

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.

[The Grand Nudger]

It's basically a two way mirrored box situation. We can't see out, "it" can see in. Privledged info.