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 Post subject: Multiple universes
PostPosted: Mon Aug 11, 2003 10:11 pm 
This Scientific American article is a very good explanation of the subject, and explains the different kinds of possible multiverses. It's not just for sci-fi geeks anymore...


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 Post subject:
PostPosted: Tue Aug 12, 2003 8:22 pm 
Okay, gwalla, posting on your topic... :P :P

Okay, I was on page three of that when I went cross-eyed... too much for the poor undergrad mathematician/philosopher....

The parts that I did get through did answer the first question that popped in my head: "Why the assumption of an infinite universe?" and it answered that in quick fashion.

Admitting I haven't got through the whole article yet... does it raise the question of the possibility that you and your doppleganger are neighbors in the sense that you could observe each other in your own life-times?


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 Post subject:
PostPosted: Tue Aug 12, 2003 8:52 pm 
Gerald wrote:
Okay, gwalla, posting on your topic... :P :P

Okay, I was on page three of that when I went cross-eyed... too much for the poor undergrad mathematician/philosopher....[/url]

Keep going (take breaks often though...it's tough going). Lots of interesting ideas. Although I'm not really comfortable with how he brings up Occam's Razor...I get the feeling that he's misapplying or misunderstanding it.

Quote:
Admitting I haven't got through the whole article yet... does it raise the question of the possibility that you and your doppleganger are neighbors in the sense that you could observe each other in your own life-times?


Not really, although it kind of depends on the kind of parallel universe you're talking about.


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 Post subject: Infinity
PostPosted: Tue Aug 12, 2003 10:02 pm 
I have not finised the article yet either, but in it's first page the author
suggests that parrell universes are sitting next to each other like
passengers on a bus. Other scientists claim there is missing mass in
our bunch of galaxies. If the other realities were next to us in
5th, 6th, and 7th dimensions, then their mass would count.
Normally 2 objects cannot occupy the same place at the same
time. On this other hand scientific 'truths' grow out of theories
and can be amended. There are also a lot of appearances and
disappearances waiting to be explained.
As for the infinite universe, If it's still growing then in the 4th
dimension it is infinite. The so called cosmic noise from the
big bang, is it fading? If not maybe it's still going on at the
edges of our detectable universe.
As for the matter and energy that gets crushed into black holes,
does it trudge all the way to the next universe in a wormhole?
More likely it sqirts into interstitial space. I think that cosmic
mush is what fuels the paranormal. It may have once fueled
magic before the church wiped that out.
Anyways I will try to read more of the article.


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 Post subject:
PostPosted: Thu Aug 21, 2003 3:07 am 
http://slate.msn.com/id/2087206/

Slate's "Egghead" column tackles the multiverse, and summarizes some arguments for and against the idea. It's intersting to compare what Jim Holt considers good and bad reasons for believing in a multiverse to the Scientific American author's views.


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 Post subject: Universes
PostPosted: Fri Aug 22, 2003 2:30 am 
Jim Holt's version has more possibilities. On the other hand my
interpretation of universe is the 20th and 21st century interpretation
of all space. And evidence of alternate universes just have to be
rare enough that the sample that ruled them out did not contain
enough to rule out random error. In another universe where Charles
Fort was a famous scientist, we may be detected before we notice them.
Judging by the time it took for man to realize meteors came from
outside the world it may be 2200 or so before we can detect parallel
universes. We don't need to belive in parallel universes unless
A) You have a theory with a hole in it that otherwise works.
B) You're faced with a dissapperance, appearance, or other mystery
that lacks evidence of foul play, but would be explained by a parallel
universe.
I may persue thoes other articles linked to it.


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 Post subject: Multiple universes
PostPosted: Wed Sep 03, 2003 4:54 pm 
I rather like Larry Niven's objections to multiple universes, in the sense of every-possible-combination exists somewhere. Okay, imagine you have some really momentous decision that you really sweated about. Getting married. Moving to take a new job. Having a child.
Then stop to think that no matter WHAT you decide, some other YOU will decide differently. Now don't you feel silly?
And if you think that's silly, consider the one of you that still can't make up their mind....
I'm with Davies. It's too extravagant, and Occam's razor slices away multiple universes without evidence rather neatly. If it was the ONLY way you could explain some of the phenomena, that would be one thing. Luckily, from quantum mechanics to anthropic coincidences, there are other possible explanations.
And in any other argument, if I invoke Occam's razor---that a simpler explanation, with fewer possible things interacting---is to be preferred over a more complex one---would be accepted immediately.
Otherwise pre-Copernican "epicycles" would be JUST as reasonable as the Copernican universe.
And we all know it isn't.---Al


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 Post subject: Re: Multiple universes
PostPosted: Wed Sep 03, 2003 11:27 pm 
Al Schroeder wrote:
And in any other argument, if I invoke Occam's razor---that a simpler explanation, with fewer possible things interacting---is to be preferred over a more complex one---would be accepted immediately.
Otherwise pre-Copernican "epicycles" would be JUST as reasonable as the Copernican universe.
And we all know it isn't.---Al

Copernican epicycles weren't much more reasonable than pre-Copernican ones. Copernicus had a little trouble matching planetary movements to his circular orbits.


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 Post subject: Multiple universes?
PostPosted: Thu Sep 04, 2003 5:21 am 
Good point. But if I had said post-Keplerian universe (or whoever it was who proposed ellipses rather than perfectly circular orbits) how many people would have known what I was talking about?--Al


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 Post subject: Re: Multiple universes?
PostPosted: Thu Sep 04, 2003 8:47 pm 
Al Schroeder wrote:
Good point. But if I had said post-Keplerian universe (or whoever it was who proposed ellipses rather than perfectly circular orbits) how many people would have known what I was talking about?--Al


/me raises his hand


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 Post subject:
PostPosted: Thu Sep 04, 2003 9:42 pm 
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Posts: 1634
We're arguing on a forum about science, among a bunch of very intelligent individuals. The easier question would be "who wouldn't?"

Vorn


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PostPosted: Tue Sep 30, 2003 3:05 am 
Every possible outcome has a universe? I think not.
That's like saying every star has planets. All the patterns I've seen
suggest some stars have planets galore while most get none.
In other words some decisions are monumental and may spawn several
universes. My life probably spawns none. Piling infinite universes into
the equation just ruins your results. And that guys razor might not be
kind to the idea of all the subatomic particles suddenly deciding
to disintegrate one specific individual while sparing all the rest of the
world. Quantum theory is pretty much based on the idea that subatomic
particles are smaller bits of matter. Actually they should be less solid
then energy so you are dealing with an electric field around an atom
with an electric power of 20 electrons but no actual solid electron particles. If an ice cube melts on a table it's not one ice cube in 7
places at once. It's a puddle of water.


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 Post subject: My Point is...
PostPosted: Tue Sep 30, 2003 3:13 am 
Sorry for replying to myself but I wanted to isolate my point.
One man slipping from universe A to universe B is simpler then
all the atoms he is composed of suddenly turning into thin air.
There are cases of spontanious human combustion and it leaves
an awful mess.


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PostPosted: Tue Sep 30, 2003 10:22 am 
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Goth Guru, now you're mixing philosophy and science. The quantum multiverse theory requires a new universe for every time a quantum decision is taken. For example, a photon travelling by its lonesome through a slit acts as though it's interacting with the slit and with non-existent photons all around it. To explain this result, multiverse quantum theory states that a universe exists for every possible path the photon could have taken - were in fact created specifically for the purpose of the decision - and the interaction of these universes 'decides' where the photon ends up in our universe. This version of the theory also goes on to state that these universes most likely continue existing afterwards and can never again be contacted. Since we know that any interaction whatsoever - also those that contribute to thought - involve quantum scale effects, all possible outcomes, including, but certainly not limited to, me not posting this reply, me having attrocious spelling, my computer crashing before I can post this, and me suffering spontaneous combustion just now, will have happened somewhere. Though most will be permutations of the most likely result, that is, my finishing this post, and succesfully posting it, all other possibilities do exist.

Just think, if multiple universes exist, somewhere out there, there's a version of you that suddenly and violently burst into flame walking out the front door this morning...

Regardless, in a quantum multiverse, ALL possible outcomes exist, not just what we would, very humanocentrically, consider 'important'. You're using 'human' logic. Don't.

Henk G.

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 Post subject:
PostPosted: Tue Sep 30, 2003 2:10 pm 
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that and spontaneous human combustion isn't spontaneous. You actually have to catch yourself on fire first.

Vorn


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 Post subject:
PostPosted: Fri Oct 03, 2003 11:03 pm 
The quantum multiverse theory requires all the possible universes
never have contact again, including gravity. No help in finding the
missing mass in the universe, explaining people that vanish, or
objects that fall out of the sky.
So nobody was saying Quantum Mechanics was involved. Good.
As for how many adjacent universes there are if you are willing to
consider a limited number of branching universes, here is a formula.

Let the known mass of the universe = Known Mass = KM.
Let the mass the universe needs to function = Needed Mass = NM.
The number of adjacent parallel universes = Local Group Universes = LGU.
NM / KM = LGU

Anyone know where I can find the first 2 numbers?


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 Post subject:
PostPosted: Sat Oct 04, 2003 12:12 am 
Goth Guru wrote:
The quantum multiverse theory requires all the possible universes
never have contact again, including gravity.


I thought that the Everett Hypothesis (The original explanation of multiple universes, or the 'choice-derived' multiverse hypothesis) stated that the universes nearest each other had to be interacting, constantly. Else we couldn't get single-photon scatter from a double-slit experiment. I'm gonna hafta look that one up and show everybody, right?

It'll take me a while. Fortunately, I'm at a place that does X-TREEM QUANTUM RESEARCHOSITY, so I can take a whack at this.


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 Post subject:
PostPosted: Sat Oct 04, 2003 8:36 am 
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Reptile House Exhibit
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Goth Guru wrote:
Let the known mass of the universe = Known Mass = KM.
Let the mass the universe needs to function = Needed Mass = NM.
The number of adjacent parallel universes = Local Group Universes = LGU.
NM / KM = LGU

Anyone know where I can find the first 2 numbers?

We're at about an omega (ratio of the known mass of the universe over the required mass of the universe for it to neither ever collapse nor expand to infinity) of 0.1. If we assume that all subuniverses have equal mass, you just placed a limit of about ten on the number of parallel universes. If we assume each sub-universe takes half of the mass of the parent (more reasonable IMHO), we have a lower limit of 5, and an upper limit of 16.

Honestly, go find yourself some books on physics, or talk to a professor at your local university. You're way out of line with any respectable current theory. It's an interesting postulate, but not a practical one. The quantum multiverse theory was created to explain things like single-photon scatter in a double-slit experiment (thanks for the correction, Foxeryn). Your multiverse does not contain enough universes to do so, hence multiverses are not necessary (as the explanation for quantum events must be sought elsewhere). Whatever your version of the multiverse is called, it is emphatically not part of 'quantum multiverse theory.'

And the disruption caused by the removal of a significant portion of the universe's mass does not even bear thinking about... And bonus: All current observations point to the fact that the universe is stable, i.e. that omega is very, very close to one. If BB is true, and if we only 10% of mass left after a number of splits, the universe is now heading for rapid dissolution, which we see no evidence of.

Foxeryn; to my best knowledge, the current accepted version of the multiple universe theory states that the universes only interact during the one event they were created to mediate, afterwards going their seperate ways. But if you find out otherwise, let us know, especially if you get some good book recommendations out of it.

Henk G.

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PostPosted: Wed Oct 08, 2003 3:44 pm 
htg wrote:
Goth Guru, now you're mixing philosophy and science. The quantum multiverse theory requires a new universe for every time a quantum decision is taken. For example, a photon travelling by its lonesome through a slit acts as though it's interacting with the slit and with non-existent photons all around it. To explain this result, multiverse quantum theory states that a universe exists for every possible path the photon could have taken - were in fact created specifically for the purpose of the decision - and the interaction of these universes 'decides' where the photon ends up in our universe. This version of the theory also goes on to state that these universes most likely continue existing afterwards and can never again be contacted. Since we know that any interaction whatsoever - also those that contribute to thought - involve quantum scale effects, all possible outcomes, including, but certainly not limited to, me not posting this reply, me having attrocious spelling, my computer crashing before I can post this, and me suffering spontaneous combustion just now, will have happened somewhere. Though most will be permutations of the most likely result, that is, my finishing this post, and succesfully posting it, all other possibilities do exist.

Just think, if multiple universes exist, somewhere out there, there's a version of you that suddenly and violently burst into flame walking out the front door this morning...

Regardless, in a quantum multiverse, ALL possible outcomes exist, not just what we would, very humanocentrically, consider 'important'. You're using 'human' logic. Don't.

Henk G.


I saw a T.V show on something like that. Grant it was on the Disney Channel, it talked about how there could be different universes on the outcomes of every single thing that happens. Like if you wake up this morning and you wear a red shirt, in another universe your wearing a blue shirt. In the show, the charcter has an incounter with one of her double, when the double some how drops into her demension (I think it would be very different if both demensions were mused), and for some reason she has become somewhat of a badass.

I would also like to state one other thing. If this theory is true, should we really call our duplicates ? there not actually us? there not exactly you, right?

I also have a small other theory. If the universe is expanding, then it must be exapnding in something. So I'm guessing that there would be other universes, the harder thing to beleive in would be different demensions, or realities. The universe wouldn't be infinite, but space in general would.

In another universe, I might have typed this with proper grammer and spelling. :D :D


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PostPosted: Wed Oct 08, 2003 8:22 pm 
Luna Lovegood wrote:
I saw a T.V show on something like that. Grant it was on the Disney Channel, it talked about how there could be different universes on the outcomes of every single thing that happens. Like if you wake up this morning and you wear a red shirt, in another universe your wearing a blue shirt. In the show, the charcter has an incounter with one of her double, when the double some how drops into her demension (I think it would be very different if both demensions were mused), and for some reason she has become somewhat of a badass.


I again point at Hugh Everett's ever-popular Multiple Worlds Interpretation, which is the original theory behind that show.
http://www.hedweb.com/manworld.htm wrote:
What is many-worlds?
AKA as the Everett, relative-state, many-histories or many-universes interpretation or metatheory of quantum theory. Dr Hugh Everett, III, its originator, called it the "relative-state metatheory" or the "theory of the universal wavefunction" [1], but it is generally called "many- worlds" nowadays, after DeWitt [4a],[5].

Many-worlds comprises of two assumptions and some consequences. The assumptions are quite modest:
1) The metaphysical assumption: That the wavefunction does not merely encode the all the information about an object, but has an observer-independent objective existence and actually is the object. For a non-relativistic N-particle system the wavefunction is a complex-valued field in a 3-N dimensional space.

2) The physical assumption: The wavefunction obeys the empirically derived standard linear deterministic wave equations at all times. The observer plays no special role in the theory and, consequently, there is no collapse of the wavefunction. For non-relativistic systems the Schrodinger wave equation is a good approximation to reality. (See "Is many-worlds a relativistic theory?" for how the more general case is handled with quantum field theory or third quantisation.)


Luna Lovegood wrote:
I would also like to state one other thing. If this theory is true, should we really call our duplicates ? there not actually us? there not exactly you, right?


You'd call them "That other me", if you ever ran into them, or call them by name.

Luna Lovegood wrote:
In another universe, I might have typed this with proper grammer and spelling. :D :D


Hello, Other Luna.


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