How is the Universe here?

Despite the constraints on my time, I feel a thread on this is long overdue given its prominence in the EvC debate. I want to go beyond the usual confused discussions around the Big Bang, and look at more generalised concepts (though the BB will be covered as an example in various sub-threads.) I want to look at our understanding of time, beginnings, endings, infinities, somethings-from-nothings, etc. I should stress that this will be firmly based on our understanding of relativity, with inspiration from string theory, loop QG, etc, and some quantum theory, but we will be using this to launch into *informed* speculation. The main goal is to break down common prejudices and misunderstandings - if by the end you feel you know less than when you staretd, that's not necessarily a bad thing Once (if) this is promoted, I think we'll begin with time.Big Bang and Cosmology please.Edited by cavediver, : No reason given.

Thread moved here from the Proposed New Topics forum.

Ok, time...Einstein's Special Theory of Relativity introduces us to the concept of time as a dimension, very similar to our three spatial dimensions. (The clue to this was in Maxwell's Equations of electromagnetism, which could be written in exceptionally simple form once time was treated as the fourth member of the (x, y, z ) set.)But this wasn't actually the biggest shake-up to our concept of time. Space-time was actually already an existing concept with Newtonian phsyics, and we can easily imagine a simple 4d space-time reality, with time perpendicular to the space. A cross-section of this space-time gives the Universe at a particular time, and the experience of time is essentially this "now" cross-section inexoriably marching forwards in time, carrying our experience with it. Imagine a tall stack of paper: each sheet of paper is space at a different time. My life would start on one sheet and would trace a path upwards through each sheet of paper until we reach the sheet of my death. At any particular moment, I am sat on a particular sheet. Everything that occurs on that sheet, occurs "now". Anything on lower down sheets happened in the past, and anything that occurs on sheets above, happens in the future.SR showed this to be incorrect. There is no universal cross-section of the Universe, no universal now. Each of us has our own path through space-time, and we each define our own "now", which will not necessarily agree with someone else's "now". My "now" is no longer the piece of paper I'm sat on, but rather a a slice through the stack of paper at an angle, and your "now" might be a different slice, so that some things I regard as happening in my past, you may regard as yet to occur.So our first lesson is that although time is a universal dimension, our experience of time is completely individual.Before I bring in the changes Genral Relativity introduces, I'll pause for some discussion/questions.Edited by cavediver, : No reason given.

Is the universe really here? Or is it here only in superpositions that decohere and in which we appear to happen to be(obviously we are in the same decohered state of the universe)? Is there any chance that i might one day see me in my house in Varna and be in Paris at the same time? Could a scientific experiment be made that would prove me being in a superposition of states in different parts of the Earth before i decohere with the environment? If there is no movement in the quantum world, but a transition from one state of superpositions to the other, then what exactly is space and the universe before they decohere?Why did the universe decohere in a state that would produce consciousness? Do you believe it happened by chance that we got such a coarse apparatus that is letting us experience reality as a continuous process? Would you really say the universe exists outside of our minds?What happens to the other branches? Do they still exist?More to the point - Why is the universe here? I'd say the superposition of states of the universe are here because a higher intelligence wants it so. Edited by Agobot, : No reason given.

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"Science without religion is lame. Religion without science is blind" - A.Einstein"I am a deeply religious nonbeliever - This is a somewhat new kind of religion" - Albert Einstein"Matter is nothing but the harmonies created by this vibrating string..The laws of physics can be compared to the laws of harmony allowed on the string. The universe itself, composed of countless vibrating strings, would then be comparable to a symphony." - Michio Kaku

Although obviously relevant, I want to stay away from quantum interpretation for now, in this thread at least.

Why not?

Better?

Hahahahaha. Yes.

I am not sure most folks would understand this quoted paragraph, but then most them wouldn't care, as long as they have a holy book or as long as they believe there is no god because the bible is wrong.
Yep, time is not a straight line but a river that can have whirpools, fork in two rivers and perhaps even be bent. I once heard that time travel was possible, but would take the energy of a star like our sun... Talk about scales, HAHA...BTW, sorry for attempting to decohere your thread into QM interpretations. I am looking forward to your next post. Edited by Agobot, : No reason given.

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"Science without religion is lame. Religion without science is blind" - A.Einstein"I am a deeply religious nonbeliever - This is a somewhat new kind of religion" - Albert Einstein"Matter is nothing but the harmonies created by this vibrating string..The laws of physics can be compared to the laws of harmony allowed on the string. The universe itself, composed of countless vibrating strings, would then be comparable to a symphony." - Michio Kaku

Speaking of time i would consider the existence of wormholes in space that arise out of GR, that could allow us to travel immense distances in short time(and even time travel), a kind of a gift from the creator/s/. That would be just too many coincidences that facilitate our development and our conquest of space, but let's hope we don't get into another world war and go the way of the dinosaurs.Edited by Agobot, : No reason given.Edited by Agobot, : No reason given.

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"Science without religion is lame. Religion without science is blind" - A.Einstein"I am a deeply religious nonbeliever - This is a somewhat new kind of religion" - Albert Einstein"Matter is nothing but the harmonies created by this vibrating string..The laws of physics can be compared to the laws of harmony allowed on the string. The universe itself, composed of countless vibrating strings, would then be comparable to a symphony." - Michio Kaku

This has the potential for being an interesting thread. I think it will do better if you stay out of it Agobot.You may as some questions, questions only! Stay very, very close to the topic or this will cease to be a request.Thank you.

How does the idea of ever increasing entropy fit into individual, as opposed to universal, time?Is our view of the total entropy of the universe also individual if our view of time is individual? Or can the concept of entropy be used to relight the idea of universal time existing in some sense after all?I may be taking your sheets of paper anology too far...... But is it thought that time moves forward in discrete "sheets" (i.e. is it quantised) or does it "flow" in much the way we individually perceive it to?

Are you saying that an event in my past may be an event in your future? I don't get it! Both of us set our watches by Greenwich!

I see things that happen as that the past is past so happenings can not reoccur in the natural. I'm not against the past present and the future time is connected that the atom is not pointlike but part of this river of time connection believed by some founded on nothing that we're all experiencing. However these dimensions of time does not seem to be allowing anyone to experience something in real time happening before another experiences the same happening.The earth is it not moving thru space and time so for an happening to happen before another shared the same happening how is this not placing the cart ahead of the horse? Would not the second person need to be going backwards in time to a space time coordinate where the earth was when this happening on the earth occurred?

Hello John,
I think what cavediver is presenting is best understood with a review of light cones. It takes time for any event to reach an observer. So lets say we had a solar flare large enough to notice the visual effects on Earth. If it happened around dusk. You would see Venus brighten first than several minutes later you would notice Jupiter brighten. So the light cone can be in Earths/ Venus's past while still being in Jupiters future.Abe- Cavediver, I would really enjoy discussing the point Straggler brought up about entropy and how that might relate to universal time. (I know universal time is the wrong wording for it, since time is relative to the observer.) But wouldn't the universe entropy at the same or close to the same rate regardless of observation. No rush when we get to it.Edited by rueh, : No reason given.