I thought I'd listen to Two Steps From Hell - Victory.
It sounds like the backing music for a bank TV advert.
It sounds like the backing music for a bank TV advert.
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I know the idea of another 'me' out there in our universe is totally hypothetical and possibly not provable one way or anotherAgain: If
do they need to take into consideration what happens to 'me'I don't think this can be answered without a definition of what you consider 'me' to mean.
But for those who have indicated the possibility of this being the case, have they or do they need to take into consideration what happens to 'me' and our universe before relativity, at the uncertain quantum level?Not sure how relativity would come into it, but if you don’t know of their existence then it would be impossible to take into account what happens to them.
I have often read about infinite numbers of infinite universes and that there will be another 'me' doing exactly what I am doing now at this exact time. If I am the product of the laws of physics in 'our' universe, and there are an infinite number of universes, could there not be an infinite variety of the laws of physics applying to each universe which could mean there would never be another me?The point was that our one universe was large enough that there are other copies of you in this universe, never mind any hypothetical other ones. If they're not doing exactly what you're doing now, then they're not exact copies, are they? Depending on your QM interpretation of choice, these might be very (but computably) distant, or quite close, or completely nonexistent.
could there not be an infinite variety of the laws of physics applying to each universe
The triangle ,according to the programme is evidence that space (spacetime?) is probably flatSpace is flat, not spacetime, as I go into below (bold)
Inertial coordinate systems, or 'coordinate space' (adjusted for local wiggles for local masses) for instance require (at the largest scales at least) flat Minkowskian spacetime. Space may be flat but spacetime certainly isn't. Such coordinates are subtlety dropped for cosmological coordinates in any situation where the two differ significantly, which is over several billion light years. So for instance, consider visible galaxy X. In cosmological coordinates, the time there is currently 13.8 BY (same as it is anywhere), it is 16.5 BLY away, receding at a rapidity of 1.2c, and the light from that event will never get here because it's somewhat outside the event horizon. Same object in the inertial frame of Earth: The time there is about 8.3 BY. It is about 11.4 BLY away, receding at a velocity of about .83c, and the light from that event should get here in 11.4 billion years, but it won't so that's a contradiction. The coordinate system doesn't work at that scale.and no other <reasonable> coordinate system reaches that far awayI'm admittedly confused as to why you say this. There is a limited distance for coordination systems?
This again assumes that the universe has a state, unmeasured.Would not the living things on that hypothetical, far away planet count as doing measurements by making observations? Or are we entering "Wigner's friend" territory?[/quote]
But isolated systems don't exist.
and no other <reasonable> coordinate system reaches that far away
This again assumes that the universe has a state, unmeasured.
I'm not sure I fully understand your reply. Are you saying there is some reason that there cannot be a planet out there somewhere that is identical down to the subatomic level to the way the Earth was 60 million years ago?Yes, it can exist, but only 60 million years ago as measured by cosmological time. It can't exist 'now' relative to that coordinate system, and no other <reasonable> coordinate system reaches that far away, but I suppose you could do a custom ad-hoc foliation of spacetime that just asserts that this remote dino-laden Earth happens to be simultaneous with 2021 here.
I see it the other way round.For there to be an identical system to another it has to have identical connections to its environment.There are connections only to the volume's past light cone, so an identical Earth only needs to have identical past with ours, which reaches out at best less than 6 billion LY out. No event in our causal past has ever been further away from 'here' than that, so only the state within that light cone matters, not the whole state of the observable universe, the vast majority of which is not in our current causal past and not even in the causal past of any possible future state of Earth for that matter. It's not what they mean by 'observable universe'.
then Earth does indeed occur at an infinite number of places, but not at different times since the age of the universe is part of the current state of Earth.
@Kryptid I see it the other way round.For there to be an identical system to another it has to have identical connections to its environment.
The implications of an infinite universe are pretty startling, actually. When you have an infinite amount of matter and energy with a relatively random distribution throughout space, then every possible scenario will have happened an infinite number of times in the past (so long as the scenario doesn't require longer than the current age of the Universe to occur) and will continue to happen an infinite number of times in the future.I must disagree. The current state of Earth can have only happened now and not in the past or later. Given an infinite universe (and a couple more assumptions, notably that the universe is in fact everywhere in some state, a premise which I find implausible), then Earth does indeed occur at an infinite number of places, but not at different times since the age of the universe is part of the current state of Earth. There can never be one like it again, because in the future the universe (visible from this hypothetical future Earth) will be in a state of higher entropy than can be measured from this future Earth.
But can we begin to tentatively assume that the observable universe may well be part of an (dynamic) infinite structure?That (the infinite part) has pretty much been the assumption all along, and all this latest finding only shows that it is flat to more zeros than had previously been measured. Any positively curved space would imply a finite volume just like Earth's surface is positively curved and thus has finite area despite the limited extent of the visible part of it. There's no edge. You can travel indefinitely and never get to a boundary, and yet the area is finite.