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Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Sun Nov 14, 2010 9:09 pm
by bystander
isoparix wrote:Everything that is Provable is True, but not everything that is True is Provable - and we can prove that. Or saying it another way, Everything that is Falsifiable is False, but not everything that is False is Falsifiable. And that should keep us all on our guard, in all sorts of fields....
Falsifiability or refutability is the logical possibility that an assertion could be shown false by a particular observation or physical experiment. That something is "falsifiable" does not mean it is false; rather, it means that if the statement were false, then its falsehood could be demonstrated.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 2:24 am
by Occam
Without any empirical data to support the notion of an alternative universe, the use of the word "hypothesis" is scientifically inappropriate.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 2:25 am
by sea otter
This APOD has opened my eye to a new universe of ideas.
I clicked on the Clifford Pickover link and discovered much fun fresh stuff.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 2:26 am
by Spock
I mean if we are going to put up pics of imaginary things--why not the USS Enterprise in orbit around Regula 1
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 2:54 am
by rstevenson
Spock wrote:I mean if we are going to put up pics of imaginary things--why not the USS Enterprise in orbit around Regula 1
So, Mr. Spock, when did you first begin to suspect that life was an illusion?
Rob
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 3:14 am
by Ann
Occam wrote:Without any empirical data to support the notion of an alternative universe, the use of the word "hypothesis" is scientifically inappropriate.
I've always thought that "hypothesis" is the word you use for a systematic description of the world that you arrive at by guessing at a starting point and working out where you would logically have to go from there. Maybe obsevations will show that the starting point you guessed at really does exist in the real world and really does affect how the real world works. Once you find sufficient support for the predictions that follow from your hypothesis, your hypothesis becomes a theory.
Or that is what I thought anyway.
Ann
P.S. This is my 936th post, and I'm feeling very yellow today.
NGC 936.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 3:44 am
by Isaiah 40:26
If in any other universe there exists an exact duplicate of the Internet, I wonder if its APOD actually featured an Astronomy Picture Of the Day. I wish I were there.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 6:18 am
by OzRattler
rstevenson wrote:
So, Mr. Spock, when did you first begin to suspect that life was an illusion?
Rob
Ah.... to quote Mr Spock....
"It's life Jim, but not as we know it......"
Or was that Weird Al???
In any event, the Klingons against multi-verses will just be angry....or would they be calm?
Rrrrrrrrrrrrrrr
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 8:12 am
by steveb59
Other universes, to be considered parallel to our one, must share nothing. Well, I can't think that they don't share almost time with us.
On the other hand, a scientific demonstration of the existence of a parallel universe must be based on something that is shared. So these two universes are in contact, and not parallel.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 4:18 pm
by nz1m
So what is "between" them?
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 4:31 pm
by smitty
An administrative question: why isn't the APOD for 14 November 2010 listed in the APOD archive? It still wasn't listed as of mid-day on 15 November.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 15, 2010 8:26 pm
by DavidLeodis
alter-ego wrote:Although I'm not proponent of exact-copies, I like the idea of multiverses. It's getting a stuffy around here - I need a breath of fresh space.
That may of course be just what those out there are also thinking!
![Smile :)](./images/smilies/icon_smile.gif)
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Tue Nov 16, 2010 3:43 am
by Jean Develet
bystander wrote:Jean Develet wrote:expands to the Big Crunch
??? How does one expand to a crunch ???
Imagine a 2D surface of a 3D sphere*. An explosive expansion of many particles restricted to the 2D surface from a surface point continues along the surface till at 180 deg away they all combine into a crunch point. This is an analog of my above description of the Universe being the 3D surface of a 4D sphere*. The Big Bang causes the expansion of particles in our 3D universe. The geometric nature of the 3D surface being on a 4D sphere ultimately causes all particles of the Universe to crunch 180 deg away. Particles of our Universe are restricted to the third dimension. Gravitational force in the crunch causes the observed acceleration we see and define as Dark Energy.
This is my assessment of our Universe based on the reference below and also on observed distant accelerations. Of course continued observations and measurements are necessary to validate this assessment.
*Reference: "A Brief History of Time", Stephen W. Hawking, A Bantam Book/April 1988, p.p. 137-138.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Tue Nov 16, 2010 4:41 am
by Chris Peterson
Jean Develet wrote:Imagine a 2D surface of a 3D sphere*. An explosive expansion of many particles restricted to the 2D surface from a surface point continues along the surface till at 180 deg away they all combine into a crunch point. This is an analog of my above description of the Universe being the 3D surface of a 4D sphere*.
You misunderstand the analogy. In the 2D case, the "explosion" is from the center of the balloon, which is a 3D point, and results in the expansion of the surface of the balloon, a 2D surface. This analogy is intended to help visualize the expansion of the Universe, which has its origin at a 4D point, with a consequent expansion of the 3D manifold we observe. There is no "other side" where things come together.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Fri Nov 19, 2010 7:48 am
by x00x
Two comments.
1. Sorta re-defines "big" in a big way, don't you think?
2. The title "Astronomy Picture of the Day" conveys the sense of imagery that is uniquely alien in otherworldly beauty, exotic in its splendor, the sort of visual grandiosity we have come to expect of APOD.
I came across the image you've posted for Multiverses:Do Other Universes Exist? having first seen it listed in the APOD archive, the title tantalizing me in anticipation of the sort of breathtaking image I might expect only to let me down in woeful disappointment with your horrendously amateurish, tacky visualization that belies the otherwise profoundly beautiful imagery APOD is so well renowned for.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Sun Nov 21, 2010 1:35 pm
by Occam
Ann wrote:I've always thought that "hypothesis" is the word you use for a systematic description of the world that you arrive at by guessing at a starting point and working out where you would logically have to go from there. Maybe obsevations will show that the starting point you guessed at really does exist in the real world and really does affect how the real world works. Once you find sufficient support for the predictions that follow from your hypothesis, your hypothesis becomes a theory.
The definition of "hypothesis" is "educated guess." In my haste to get out an answer, I substituted "empirical data" for scientifically appropriate education, and I overstated my point. Since science deals exclusively with observable phenomena, no amount of scientific education could arrive at an hypothesis of alternate universes.
One might as well call divine intervention or intelligent design a scientific theory.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Sun Nov 21, 2010 3:01 pm
by Chris Peterson
Occam wrote:The definition of "hypothesis" is "educated guess." In my haste to get out an answer, I substituted "empirical data" for scientifically appropriate education, and I overstated my point. Since science deals exclusively with observable phenomena, no amount of scientific education could arrive at an hypothesis of alternate universes.
One might as well call divine intervention or intelligent design a scientific theory.
Not at all. There is nothing unscientific about hypothesizing the existence of alternate universes, and then constructing a theory around that hypothesis. Science does not require direct observations to reach conclusions. An alternate universe theory might predict some particular observable feature of our own universe- for instance, a specific structure of the CMB. This then becomes a test which can either disprove the theory, or add support to it.
There is no inherent reason we can't ultimately have a lot of confidence about the conditions that existed "before" our universe was formed, or which existed (or exist) "outside" it, even though the direct observation of these things is impossible.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 22, 2010 2:16 am
by Occam
Chris Peterson wrote:Occam wrote:The definition of "hypothesis" is "educated guess." In my haste to get out an answer, I substituted "empirical data" for scientifically appropriate education, and I overstated my point. Since science deals exclusively with observable phenomena, no amount of scientific education could arrive at an hypothesis of alternate universes.
One might as well call divine intervention or intelligent design a scientific theory.
Not at all. There is nothing unscientific about hypothesizing the existence of alternate universes, and then constructing a theory around that hypothesis. Science does not require direct observations to reach conclusions. An alternate universe theory might predict some particular observable feature of our own universe- for instance, a specific structure of the CMB. This then becomes a test which can either disprove the theory, or add support to it.
There is no inherent reason we can't ultimately have a lot of confidence about the conditions that existed "before" our universe was formed, or which existed (or exist) "outside" it, even though the direct observation of these things is impossible.
Hi Chris,
Thank you for your reply. If I understand it correctly, I believe it may be internally inconsistent. You may be using the common definitions of "hypothesis," "theory," and possibly "science" not the scientific definitions.
From wikipedia (I chose this definition because it is concise, readily accessible, and comes with references, not because I'm not skeptical about what I find there, or because I think the definition is the best one.) the definition of science is: Science (from the Latin scientia, meaning "knowledge") is an enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the natural world.
Science *does* require observation in order to test explanations. The notion of a parallel universe cannot be observed. It's a stretch to call that notion an hypothesis in a scientific sense. If it makes a testable prediction that is not readily explained by existing theory, then it enters the realm of science. Note however, that in order to test a prediction, one has to make an observation. If your mental exercise does not make a testable prediction, then it is not science, but rather the free play of creative imagination: fantasy.
I did not say that scientific observations need to be made directly. For example, Robert Millikan measured the fundamental charge of an electron, but that was not done directly.
And as far as having confidence in what took place before the beginning of our universe as we understand it, science has no explanation of that. In fact, science has no good explanation for what took place in the first few milliseconds of our universe, except that the rules of physics, or our best models of the physical universe as derived by science, did not apply.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 22, 2010 2:34 am
by Chris Peterson
Occam wrote:Science *does* require observation in order to test explanations. The notion of a parallel universe cannot be observed. It's a stretch to call that notion an hypothesis in a scientific sense. If it makes a testable prediction that is not readily explained by existing theory, then it enters the realm of science. Note however, that in order to test a prediction, one has to make an observation. If your mental exercise does not make a testable prediction, then it is not science, but rather the free play of creative imagination: fantasy.
I did not say that scientific observations need to be made directly. For example, Robert Millikan measured the fundamental charge of an electron, but that was not done directly.
I agree with most of what you say here, except for one point- the idea that a parallel universe can't be hypothesized (in the usual scientific sense of the word) because it can't be observed. To be a scientifically valid idea, it is only necessary to have a theory that makes predictions, and then have a way of testing those predictions. My example suggested the possibility of an alternate universe theory that predicted things we could observe in our own universe, such as CMB structure.
And as far as having confidence in what took place before the beginning of our universe as we understand it, science has no explanation of that. In fact, science has no good explanation for what took place in the first few milliseconds of our universe, except that the rules of physics, or our best models of the physical universe as derived by science, did not apply.
It is certainly true that science currently has little to say about the earliest moments of the Universe, or about what "caused" the Universe. And that may always be the case. But not necessarily so. I find it very interesting that some fairly speculative ideas about how the Universe came about- ideas that would have been utterly unscientific just a few years ago- are now well accepted as quality science because they predict observable features. It isn't that most people think (for now, at least) that these theories are correct, but it is recognized they meet the test for being science and not mere speculation.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 22, 2010 4:13 am
by NoelC
If we are, hypothetically, just a simulation on God's laptop - His project for Simulation 302 class at Supreme Being U perhaps - then are there other simulations with slightly different parameters? Files in the directory next door to ours perhaps? Or simulations on other Students' computers... Maybe someone else got the public/private attribute of the variable that entangles photons in this universe right...
-Noel
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 22, 2010 5:29 am
by Chris Peterson
NoelC wrote:If we are, hypothetically, just a simulation on God's laptop - His project for Simulation 302 class at Supreme Being U perhaps - then are there other simulations with slightly different parameters? Files in the directory next door to ours perhaps? Or simulations on other Students' computers... Maybe someone else got the public/private attribute of the variable that entangles photons in this universe right...
I can't help but to notice a slight change in the tenor of some discussions in this forum since medical marijuana became so widely available...
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Mon Nov 22, 2010 5:32 am
by bystander
It's medicinal only, Chris. I swear.
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Tue Nov 23, 2010 8:19 pm
by NoelC
Chris Peterson wrote:medical marijuana
I realize your comment was made in jest, Chris, but I have never done drugs in my 51 years as part of this planetary simulation.
Now, on the other hand, an individual who claims to recognize the kinds of comments such drugs might induce might have some personal experience...
-Noel
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Thu Nov 25, 2010 10:37 pm
by Céline Richard
Hello,
I read messages, and i see people speaking about dimensions.
I think this is important for multiuniverses, the strings theory (11 dimensions?!), and other complex and mysterious subjects.
Actually, i can imagine a 3D-Universe, but not a fourth dimension. Is there any astronomical demonstration of a possible existence of a fourth dimension?
(For instance, I was told black holes were an example of a more than 3D-structure. However, space-time seems to be a 2D-structure to my mind, and a black hole until a white fountain (if it goes out somewhere) adds only one dimension, so that the whole "space-time+black-hole" would remain a 3D-structure)
Is a computer able to simulate a fourth dimension?
Have a very good day
Céline
Re: APOD: Multiverses: Do Other Universes Exist? (2010 Nov 1
Posted: Fri Nov 26, 2010 12:02 am
by Chris Peterson
Céline Richard wrote:Actually, i can imagine a 3D-Universe, but not a fourth dimension. Is there any astronomical demonstration of a possible existence of a fourth dimension?
(For instance, I was told black holes were an example of a more than 3D-structure. However, space-time seems to be a 2D-structure to my mind, and a black hole until a white fountain (if it goes out somewhere) adds only one dimension, so that the whole "space-time+black-hole" would remain a 3D-structure)
Is a computer able to simulate a fourth dimension?
You don't really need a computer. Multidimensional math is simple- you just add a variable for each new dimension. Visualizing more than three dimensions, though... that's a different matter. Part of it is native ability, part of it is experience and good analogies. I've seen computer visualizations, but I don't think they really help.