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Author Topic:   universe- why is it here?
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 97 of 144 (136977)
08-26-2004 7:36 AM
Reply to: Message 92 by happy_atheist
08-25-2004 12:22 PM


Re: Causation and the universe
happy_atheist writes:

I still see no logical way to think of the universe as having a cause, since the concept "before the big bang" has no logical meaning whatsoever. There can be no "before" time, since the very degree of freedom that time is measured relative to would not be in existence. If there is no point in time when the universe didn't exist, what meaning can does the word "caused" have?

It's funny you should ask this; I just finished reading Paul Davies' How to Build a Time Machine, in which he deals with causality and closed time loops (among other things). There is a paragraph which I think is pertinent to your question. I will quote it from the book.

Davies writes:

Gott has become so enthusiastic about time machines he even goes so far as to suggest the entire cosmos may be one, pointing out that the universe would then be able to create itself. Just as a time traveler could, in principle, go back and become his own father (or her own mother), so the universe could loop back in time and bring itself into existence in a big bang without the need for a mysterious origin from nothing. In that way the universe will in some sense always have existed, even though time itself remains finite in the past.

One of the things Davies discusses in the book is the notion that closed time loops, such as this, need not necessarily be paradoxical; they can form completely self-consistent causal loops in which A leads to B which leads back to A. He says that despite our everyday "common-sense" regarding cause and effect, there is nothing inherently contradictory about something being its own cause.

Just to be clear, I'm not saying that I think this is how the universe came about. But I thought it was relevant to your question.

It is, at the very least, a model that solves the problem of a cause existing in an epoch that had no time in which a cause could exist. In this model, the universe would have a cause. At the moment of the big bang, the cause would simply not have happened yet.

This model would appear to answer your question about causality. Whether or not it accurately describes the reality of the universe, though, is a different matter. Either way, it's food for thought.


This message is a reply to:
 Message 92 by happy_atheist, posted 08-25-2004 12:22 PM happy_atheist has replied

Replies to this message:
 Message 98 by happy_atheist, posted 08-26-2004 10:29 AM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 100 of 144 (137124)
08-26-2004 4:01 PM
Reply to: Message 98 by happy_atheist
08-26-2004 10:29 AM


Re: Causation and the universe
happy_atheist writes:

It certainly is food for thought, and it would certainly be a nice solution if it were true.

My sentiments exactly. Personally, I don't believe that it's an accurate description of the actual state of reality (and in fairness, I don't think Davies does either), but it would be an elegant solution to the problem of the first cause. What a shame the universe rarely turns out to work in such neat, easy-to-comprehend ways, huh? Instead, it hits us in the face with such perceptual nightmares as quantum indeterminacy.

happy_atheist writes:

One thing I definately agree with from the extract is that the true nature of the universe is unlikely to be anything like we comprehend it. We only really comprehend macroscopic effects, and whenever anything strays into the quantum world a whole host of weird and wonderful things that are counter intuitive become common place.

Yes indeed. Quantum theory is replete with apparently nonsensical concepts that defy our everyday instincts. Yet that seems to be how things work at the lowest levels, so who knows what the universe's true nature is? It would be nice to have a definitive answer to some of these questions and perhaps someday we will. Unfortunately, I somehow doubt that it'll be within my lifetime.


This message is a reply to:
 Message 98 by happy_atheist, posted 08-26-2004 10:29 AM happy_atheist has not replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 103 of 144 (137208)
08-26-2004 8:35 PM
Reply to: Message 101 by happy_atheist
08-26-2004 5:03 PM


Re: Causation and the universe
happy_atheist writes:

Take the idea posted above as an example, the idea that the universe caused itself.

*takes a bow* Thank you, thank you.

Heh, but seriously, I can't take credit for that one; I just read it in Davies' book. And in fact, it's not even his idea; it is theorized by J. Richard Gott, III.

happy_atheist writes:

That is not how most people think of causation.

That's a good point. Perhaps we need to redefine the term.

It seems to me that if (and I say if) there is a cause, then it doesn't really make any difference which scenario is correct, it cannot be a "cause" in the generally accepted sense. Just using the three very general concepts of past, present and future...

The concept of a cause before the big bang is a no-brainer, as there was no "before" (at least, not as pertains to any familiar meaning of the word).

I can't really see a cause occurring with its effect i.e. at the same time. Who knows, perhaps it can but I really don't see how.

Which just leaves the future. Honestly, if we are to invoke a cause, this is the only way I can see it happening. I'm not convinced that this is an accurate model, myself, but it is a consistent model; it's plausible. A leads to B leads to A.

Which of course brings us back (no pun intended) to your point; this is not what a "cause" is generally understood to be. I think the problem is that our definition is perhaps too limiting, in this regard. In the common vernacular, a "cause" is assumed to always occur before its effect. But if it turns out that the "effect" can precede the "cause" then the common definition may be insufficient.

The problem is that I really can't think of any other way to define it without running into exactly the same problem. I could say that a cause is that which leads to an effect, results in an effect, or is the origin of an effect.

The problem is that "leads to", "results in" and "is the origin of" all prompt in us the same intuitive sense of uni-directional causality. In fact, I really can't think of any words to define it that aren't intrinsically linked to our perception of past, present and future.

So I'm afraid I'm not sure how we could define the term to accommodate this idea. Unless of course we were simply to specify that "cause and effect may occur in either direction along a timeline; from past to future, or future to past." That's the only way I can think to get around it.


This message is a reply to:
 Message 101 by happy_atheist, posted 08-26-2004 5:03 PM happy_atheist has replied

Replies to this message:
 Message 104 by happy_atheist, posted 08-27-2004 1:56 PM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 105 of 144 (137588)
08-28-2004 5:02 AM
Reply to: Message 104 by happy_atheist
08-27-2004 1:56 PM


Re: Causation and the universe
happy_atheist writes:

An excellent post Tony...

Why thank you, happy!

happy_atheist writes:

...thats pretty much what i've been trying to say from the past few posts but I wasn't able to quite articulate it properly!

I know the feeling. I have the annoying habit of being drawn to concepts I have no hope of ever understanding. As such, I often find myself trying to find words that I simply don't have. It's frustrating on so many levels.

happy_atheist writes:

I guess that'll all part of the problem of talking about something that we currently don't have a word for, leading to us trying to force square words into round concepts so to speak.

Yes, and sometimes even creating new words specifically for particular concepts isn't sufficient.

Take for example "ana" and "kata" which I brought up in my thread, Dimensional Discourse (shameless plug). These terms were coined for the expressed purpose of naming the other "direction" present in four dimensional space. You can go up and down, forwards and backwards, left and right, ana and kata.

Now that's all well and good but even creating these new terms doesn't give me any actual comprehension of that direction. It's nice to have something to call it, but this doesn't help me understand it any better because the concept of "direction" itself is firmly ingrained in my mind as always being within three dimensions of space. I think we face a similar problem here, in the sense that the concept of "cause" is likewise ingrained in our minds as that which comes first, before the "effect".

So we find the idea that something which happens today, for example, could conceivably be "caused" by something which will not happen for another hundred, thousand, million, etc years contrary to our common experience, just as we find the idea that the directions "ana" and "kata" can exist contrary to our common experience.

happy_atheist writes:

Anyway, I'd like to put forth Star Trek The Next Generation as evidence that future events can cause past effects...

Hey, a fellow Trekkie! I love you!

happy_atheist writes:

...(STTNG, that tome of scientific truth ).

Are you saying that Star Trek ever has anything but good science? Why I oughta...

As a friend of mine says (who is also a Trekkie, incidentally), you can actually use Star Trek to prove that any engineering, electrical, etc problem can always be solved by "reversing the polarity."

Incidentally, nice work thinking of that episode; it's a good example of what we've been talking about. The one you're referring to is All Good Things (terrific episode, by the way).

To explain the relevance (and yes, I know it's "Trek-science" but I think it's still a good illustration of the point)...

They scan the anomaly with an "inverse tachyon pulse" in the three time periods that Picard is jumping to (past, present and future). At first, he can't understand why it's more widely spread the further back in time he is. He later discovers that it's because it is an eruption of "anti-time" colliding with normal time, therefore its "effects" travel backwards through time.

It's finally discovered that they are the ones responsible for the anomaly; it was in fact their own tachyon pulses converging at the same co-ordinates in space, in the three different time periods, that did it. To use Data's words, "We may have created the very anomaly we've been looking for."

Of course in the end, there's the big, climactic scene where the Enterprise (in all three time periods) has to fly into the anomaly to collapse it at its focal point. At which stage, all the timelines collapse into one, revealing the ships together, at the same place and time, shortly before the anomaly collapses, destroying all three of them.

For anyone interested, take a look at http://www.startrek.com/imageuploads/200303/tng-277-picard-orders-o-brien/320x240.jpg (You may have to copy and paste it to the address bar, sorry about that.)

As with most time travel stories, paradoxically speaking, it's a nightmare, but they get around it by making the three time periods causally separate; nothing in one period would affect the other two, except where they physically intersected each other, at the anomaly.

Anyway, I hope this won't be deemed off topic. I think it's a cool illustration of the concept of reverse causality, myself. And again, I realize that it's Star Trek physics, but the point wasn't to suggest that it's scientifically accurate.

happy_atheist writes:

And there you have it, STTNG proves that causation is very much different to what we think it is lol.

Damn right! If it happens on Star Trek, it must be true!


This message is a reply to:
 Message 104 by happy_atheist, posted 08-27-2004 1:56 PM happy_atheist has replied

Replies to this message:
 Message 106 by happy_atheist, posted 08-28-2004 8:47 AM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 107 of 144 (137596)
08-28-2004 9:07 AM
Reply to: Message 106 by happy_atheist
08-28-2004 8:47 AM


Re: Causation and the universe
Heh, way ahead of you, happy; I posted the link for this some time back in this message.

This message is a reply to:
 Message 106 by happy_atheist, posted 08-28-2004 8:47 AM happy_atheist has not replied

Replies to this message:
 Message 108 by Christian7, posted 08-28-2004 7:42 PM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 111 of 144 (137790)
08-29-2004 4:50 AM
Reply to: Message 108 by Christian7
08-28-2004 7:42 PM


Re: Causation and the universe
Guidosoft writes:

GIVE ME THE LINK TO THAT LABRATORY TELEPORTATION ARTICLE.

You can find it at: http://news.bbc.co.uk/2/hi/science/nature/3811785.stm

I would imagine that there would be more up-to-date information on this by now, but I haven't checked up on it for a while. I'll take a look around some time and see if I can find anything more recent. Until then, hopefully, that link will suffice. For what it's worth, there it is. Enjoy!


This message is a reply to:
 Message 108 by Christian7, posted 08-28-2004 7:42 PM Christian7 has not replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 115 of 144 (137821)
08-29-2004 11:32 AM
Reply to: Message 113 by happy_atheist
08-29-2004 9:13 AM


happy_atheist writes:

i was lucky enough to give a presentation on teleportation at university...

Outstanding! Was it based on the same quantum entanglement principle that was used (so I understand) in the link I gave?

happy_atheist writes:

...when I was doing my physics degree.

Good stuff! So do you actually have formal qualifications in physics (or any field within physics)? Just curious...I hope you don't mind my asking.

happy_atheist writes:

It took a bit of persuading my group though, they actually wanted to talk about global warming instead! lol

Oh jeez, there's a tough decision; global warming or teleportation? Don't make me choose!


This message is a reply to:
 Message 113 by happy_atheist, posted 08-29-2004 9:13 AM happy_atheist has replied

Replies to this message:
 Message 116 by happy_atheist, posted 08-29-2004 5:24 PM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 117 of 144 (138054)
08-30-2004 10:25 AM
Reply to: Message 116 by happy_atheist
08-29-2004 5:24 PM


happy_atheist writes:

Yes, teleportation is based on the quantum entanglement principles

Heh, I know that teleportation is based on quantum entanglement. I was talking specifically about your presentation.

happy_atheist writes:

Its amazing how limited our macroscopic views of the universe are.

Indeed. The further down we go, the less clearly defined everything seems to be. Ultimately, it all becomes a probabilistic "haze" at the smallest levels.

Out of curiosity (hope you don't mind my questions), did your physics degree require an in-depth understanding of quantum theory? Because it is definitely one of the more difficult physical concepts to wrap your mind around.

happy_atheist writes:

And yes I have a physics degree, but I don't profess to be any good at physics. I didn't do as well as i'd have liked.

Perhaps not but to have received a degree you must surely have a pretty good understanding of it. They don't just hand those things out. Well, they don't at *cough* accredited universities anyway. In any case, I know how hard physics gets and I tip my hat to anyone who has earned a university level degree in the subject.

happy_atheist writes:

I've since moved on to do a masters in computer science which is going much better though

Glad to hear it.

I had a mate who did similar; studied physics (becoming quite proficient, too) but majored in computer science, even doing an extra year by honours.


This message is a reply to:
 Message 116 by happy_atheist, posted 08-29-2004 5:24 PM happy_atheist has replied

Replies to this message:
 Message 118 by happy_atheist, posted 08-30-2004 11:33 AM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 119 of 144 (138107)
08-30-2004 12:09 PM
Reply to: Message 118 by happy_atheist
08-30-2004 11:33 AM


happy_atheist writes:

Yes, we did our best to explain entanglement. Not the easiest of things to get your head around hehe.

Indeed. Depends on your audience as well, I would imagine. Some concepts are harder than others to "dumb down".

happy_atheist writes:

We also had a course in atomic physics that used a lot of quantum mechanics.

I know I keep plugging my own thread but we're already way off topic here (sorry admins) and you may be interested in some of the questions I asked. For example, the concept of the "curled up" microscopic dimensions came up, at one point, and I asked a few questions you may be knowledgeable on, if you are familiar with things on that level.

happy_atheist writes:

Pretty much the only place it didn't pop up in was relativity.

Ah yes, I understand there is something of a contention between them. They both explain things very well on their respective levels but can't be unified into a single theory of gravity, or something to that effect?


This message is a reply to:
 Message 118 by happy_atheist, posted 08-30-2004 11:33 AM happy_atheist has replied

Replies to this message:
 Message 120 by happy_atheist, posted 08-30-2004 7:37 PM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 121 of 144 (138352)
08-31-2004 3:53 AM
Reply to: Message 120 by happy_atheist
08-30-2004 7:37 PM


happy_atheist writes:

I don't know if that means either of them is wrong or that there's something more fundamental we're missing that would explain both of them.

Well, if you can figure it out you'll be in line for a Nobel Prize.

I only wish I were more familiar with the theories. Is the conflict between the physical models, themselves, or do the underlying mathematics of either model simply not balance with each other? Perhaps it's a combination of both?

Hope I'm not asking for anything too complex.


This message is a reply to:
 Message 120 by happy_atheist, posted 08-30-2004 7:37 PM happy_atheist has replied

Replies to this message:
 Message 122 by happy_atheist, posted 08-31-2004 11:18 AM Tony650 has replied
 Message 123 by Primordial Egg, posted 08-31-2004 6:57 PM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 124 of 144 (138709)
09-01-2004 2:39 AM
Reply to: Message 122 by happy_atheist
08-31-2004 11:18 AM


happy_atheist writes:

However, when you get into areas approaching the conditions of a singularity the gravitational field is so strong that even though gravity is extrememly weak it becomes important and needs to be figured into the quantum calculations. This is where the problem lies, no one has been able to figure out exactly what gravity does on a quantum level.

Ah yes, it's starting to come back to me. I've read that singularities may be "point-like" and therefore subject to quantum effects.

In fact, I've read about the attempts to unite the four fundamental forces into one single theory. A long time ago, though. I believe it was in Paul Davies' Superforce.

Something I'm not clear on; is there a defining line between the "macro" world and the quantum world, or is it somewhat "fuzzy"? Also what exactly is the quantum level? Does it deal with levels below Planck length, above Planck length, or both?

I seem to recall that quantum effects can, in principle, occur on any level. It's just that the probability becomes less and less, the higher you go, so that eventually they become virtual impossibilities.

For example, there is nothing to stop me and the chair I'm sitting on from quantum tunneling through the floor and reappearing downstairs, under the house, but due to the enormous number of particles which would have to do this simultaneously, it's a pretty fair bet that I won't. *leaps off chair*

As relativity and quantum theory are so at odds, I'm also curious about something else; does the speed of light apply at the quantum level? I imagine this would come down to whether or not we're dealing with anything below Planck length (and Planck time); does the speed of light have any real meaning there?


This message is a reply to:
 Message 122 by happy_atheist, posted 08-31-2004 11:18 AM happy_atheist has replied

Replies to this message:
 Message 126 by NosyNed, posted 09-01-2004 4:12 AM Tony650 has replied
 Message 127 by happy_atheist, posted 09-01-2004 7:22 AM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 125 of 144 (138710)
09-01-2004 2:45 AM
Reply to: Message 123 by Primordial Egg
08-31-2004 6:57 PM


Re: The Elegant Universe
Hi PE.

Primordial Egg writes:

String Theory is considered one of the best candidates for resolving this - gravity pops out as a necessary consequence.

Yes, so I've read. As I said to happy_atheist, I'm sure I've read about this elsewhere and I think it was in Superforce by Paul Davies. It was a long time ago, however, and my memory of it is hazy. It may warrant a re-read.

Primordial Egg writes:

If you have the time (3 hrs), I recommend watching a documentary NOVA ran on string theory based on the book "The Elegant Universe" by Brian Greene. The documentary isn't as good as the book, but its pretty good for a science documentary, imo.

Thanks for the recommendations and the links! Greene's book has come up in conversation here before and sounds like it would answer some of my questions so I may check it out some time. If I like it I'll have a look for the doco, too.


This message is a reply to:
 Message 123 by Primordial Egg, posted 08-31-2004 6:57 PM Primordial Egg has not replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 128 of 144 (138841)
09-01-2004 2:32 PM
Reply to: Message 126 by NosyNed
09-01-2004 4:12 AM


Re: macro quantum effects
NosyNed writes:

Have you ever seen anything on liquid Helium? It has quantum effects at a macro scale.

No, I'd never heard of this! Wow! That's just...oh...just wow! Thank you so much for the link, Ned!

You wouldn't have anything else on this, would you? Do you know of any actual footage of the experiments showing these properties? I would be very interested in seeing them, if you do.

Thanks again, I really appreciate this info!


This message is a reply to:
 Message 126 by NosyNed, posted 09-01-2004 4:12 AM NosyNed has not replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 129 of 144 (138845)
09-01-2004 2:40 PM
Reply to: Message 127 by happy_atheist
09-01-2004 7:22 AM


happy_atheist writes:

There is nothing below plank length.

Heh, I thought you'd say that but I wanted to be sure.

I'm curious, though; somebody must have hypothesized something below the Planck length, at one time or another. I'm not saying they're right, I'm just wondering if there have been any ideas about existence at that level.

Or does our current understanding simply rule it out as a possibility? Perhaps "below the Planck length" is a meaningless statement in the same way that "before the big bang" is?

Incidentally, your analogy pretty much confirmed what I thought, thank you.

happy_atheist writes:

Bose-Einstein condensation is one...

Ok, now we're entering a slightly more patchy area for me. I understand that the atoms in a Bose-Einstein condensate lose their "identity" and become more "wave-like" but I'm not an expert on this so I can't say I really understand what this actually means for the matter involved. What kind of quantum properties does the condensate have?

happy_atheist writes:

...quantum entanglement is another...

Ah yes, this is one I'll be keeping a sharp eye on, over the coming years.

happy_atheist writes:

As to a barrier between micro and macro i'd say its just a continuum. The bigger in scale you get the more macro-like things become etc. Much like in evolution, things just merge together and we're left with the impossible taks of classifying things into one group or another hehe.

Yeah, that's what I suspected. For some reason, nature just doesn't like giving us clearly defined black-and-white boundaries, huh?


This message is a reply to:
 Message 127 by happy_atheist, posted 09-01-2004 7:22 AM happy_atheist has replied

Replies to this message:
 Message 130 by happy_atheist, posted 09-01-2004 3:20 PM Tony650 has not replied
 Message 131 by happy_atheist, posted 09-01-2004 3:23 PM Tony650 has replied

  
Tony650
Member (Idle past 3348 days)
Posts: 450
From: Australia
Joined: 01-30-2004


Message 132 of 144 (139081)
09-02-2004 5:12 AM
Reply to: Message 131 by happy_atheist
09-01-2004 3:23 PM


happy_atheist writes:

Something bellow the plank length would be as meaningless as a unit of energy equal to a fraction of a quanta. One plank length of space would be the smallest building block of space time there is (assuming that spacetime is quantised, which I think it probably is).

Ok, so asking what is "below the Planck length" is kind of like asking what was "before the big bang." In a sense, "below" has no meaning with regard to Planck length, just as "before" has no meaning with regard to the big bang. The big bang is the beginning, and Planck length is the bottom.

happy_atheist writes:

Dredging things up from memory (its kinda coming back to me), it deals with the probability that all the atoms will 'condense' into the same quantum mechanical state.

I read something which described this (kind of) but I'm not sure if I got the right impression from it or if it was "dumbed down" and gave me the wrong idea.

Essentially, it described the process as the particles "piling up" on each other. Now this may have been for the sake of simplicity but does this mean that the condensate always collapses (condenses?) to a point? Can macroscopic bodies exist in this state?

happy_atheist writes:

This means that, as you mentioned, they lose their identity. If two atoms are in exactly the same quantum mechanical state they become indistinguishable (as far as I know).

Ok, just to clear up, in my mind, what we mean by "indistinguishable"...I'm not quite sure how to ask this without sounding stupid but does this mean that two particles in the same quantum state are, in some sense, the "same" particle?

happy_atheist writes:

That is the principle teleportation works on, it's why a teleported object is identicle to the original rather than just a copy.

Yes, this is something else I have trouble getting my head around. What exactly is the difference between an identical object and a "mere" copy? I suppose there must be some distinction but I'm afraid I don't see it.


This message is a reply to:
 Message 131 by happy_atheist, posted 09-01-2004 3:23 PM happy_atheist has replied

Replies to this message:
 Message 133 by sidelined, posted 09-02-2004 8:31 AM Tony650 has replied
 Message 134 by happy_atheist, posted 09-02-2004 11:17 AM Tony650 has replied

  
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