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Can the Multiverse Be Tested Scientifically?
astroengine writes: Physicists aren't afraid of thinking big, but what happens when you think too big? This philosophical question overlaps with real physics when hypothesizing what lies beyond the boundary of our observable universe. The problem with trying to apply science to something that may or may not exist beyond our physical realm is that it gets a little foggy as to how we could scientifically test it. A leading hypothesis to come from cosmic inflation theory and advanced theoretical studies — centering around the superstring hypothesis — is that of the "multiverse," an idea that scientists have had a hard time in testing. But now, scientists at the Perimeter Institute for Theoretical Physics, in Ontario, Canada have, for the first time, created a computer model of colliding universes in the multiverse in an attempt to seek out observational evidence of its existence.
String theory is math, not science.
Can the Multiverse Be Tested Scientifically?
You can test specific hypotheses related to how the parts of a multiverse might interact, but no you can't test the general concept of a multiverse since there's nothing inherent to it that requires any detactable phenomena.
There are many multiverse theories and they can all be tested.
Many Worlds: The theory that there are no real "probability waves" in QM, merely overlapping realities that diverge at the time the "waveform" collapses.
This is an easy one. Entangled particles operate using the same physics as wormholes. If one of the entangled pair is accelerated to relativistic velocities, say in a particle accelerator, they will not exist in the same relative timeframe. It would seem to follow that if Many Worlds is correct, one of the particles will be entangled with multiple instances of the other particle, which would imply that every state would be seen at the same time. If the options are left spin and right spin, you'd see an aggregate state of no spin even if no spin isn't a physical possibility. And seeing something that doesn't exist either means you're in a Phineas and Ferb cartoon or Many Worlds is correct.
Foam Universe: This is the sort described in the article.
Yes, impact studies are possible, but they're only meaningful if you have enough data and you can't possibly know if you do. You're better off trying to make a universe, preferably a very small one with a quantum black hole at the throat of the bridge linking this universe to that one. What you will observe is energy apparently vanishing, not existing in any form - mass included, then reappearing as the bridge completely collapses.
Orange Slice Universe: This conjectures that multiple, semi-independent, universes formed out of the same big bang and will eventually converge in a big crunch.
It doesn't matter that this universe would expand forever, left to its own devices, because the total mass is the total mass of all the slices. Although they are semi-independent, they interact at the universe-to-universe level. In this scheme, because there's a single entity (albeit partitioned), leptons cannot have just any of the theoretical states. The state space must also be partitioned. Ergo, if you can't create a state for an electron (for example) that it should be able to take, this type of multiverse must exist.
Membrane-based Universe: This postulates that universes are at an interface between a membrane and something else, such as another membrane.
However, membranes intersecting with the universe are supposed to be how leptons are formed, in this theory. The intersection will be governed by the topology of the membranes involved (including the one the universe resides on), which means that lepton behaviour must vary from locality to locality, since the nature of the intersections cannot vary such as to perfectly mirror variations in the shape of the membrane the universe is on. Therefore, all you need to do is demonstrate a result that is perfectly repeatable anywhere on Earth but not, say, at the edge of the solar system.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Wrong multiverse theory. And, indeed, wrong experiment. In fact, the wrongitudinal level of your post is so extreme that it should really be on K5.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I doubt that there is any possibility to observationally test such a thing, and even if some weird experiment can be devised, I doubt it would really do more than hint at, rather than prove other universes. After all, by definition these other universes are not part of ours, so we can't get at them.
But let's just assume for a minute what is likely, that it can never be proven... Will the pointy headed boffins admit that it is not science, its... well.... something akin to religion really. About as scientific as any religious belief. In which case, shouldn't we really stop the whining between the scientific and religious factions? The scientists must admit that certain things could well be true that they can't prove, and that such things are worth talking about in the same breath as "real science", i.e. the things that pretty much everyone admits is true because it is science.
Next time some pseudo intellectual proclaims "that's not science", just remember... neither is a lot of stuff that gets published under the name of science, and which nobody seems to complain about.
Don't ask in the headline! You've ruined it for the scientists; now it can't be tested scientifically anymore.
Ezekiel 23:20
Correct me if I'm wrong, but this would only "prove" the existence of (that variety of) multiverse in a very small subset of universes.
So, let's say I try to poison myself with a pill from a bottle containing 99 cyanide pills and 1 sugar pill. There is a 99% chance I'll die, and a 1% chance I'll live. So in 1% of all universes, I live. I repeat the expriement multiple times, until only 1 in 1 million universes has a surviving me in. That means that in 0.0001% of universes, a very smug version of me is winning a Nobel prize for proving the existence of the multiverse. In 99.9999% of universes, I am dead and nothing has been proven except that I really shouldn't be allowed access to the lab's supply of cyanide pills.
"This is an easy one. Entangled particles operate using the same physics as wormholes. If one of the entangled pair is accelerated to relativistic velocities, say in a particle accelerator, they will not exist in the same relative timeframe. (SNIP)"
That's a misunderstanding of entanglement. There is not per see communication between the particle. When you have an entangled particle there is not one "communicating" the other that it is getting observed. What happens is that *both* particle form a single system with the specific property that when the spin of one particle is measured , the other particle has the anti spin state. Using all sort of relativistic trick on one particle will not do anything whatsoever because there is no communication to the other particle therefor frame of reference do nothing whatsoever.
I dislike the analogy because it does not represent the true nature of QM entanglement , but think of this : you have a red ball and a yellow ball. Put one in a packet at random, keep another one hiddden in a safe on earth. Then send the packet at c speed somewhere. Openning the safe 10 years later will reveal the color of the safe ball and by extent the color of the packet ball no matter how far and that despite not being in the same frame of reference and 10 light years away.
What happens here in entanglement is similar. There is no "teleportation" at c speed of the state of one to the others. Read up on bell's inequality violation.
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
We need to get Michael Moorcock on the red courtesy phone in the lobby - stat!
The heat from below can burn your eyes out
Ever since I read The Elegant Universe years ago, I've had a number of questions related to this (as I imagine many people have). This is the first time I've seen the topic discussed by professional scientists, though, as opposed to people like myself with a hobby interest in the subject or in science fiction (Alastair Reynolds makes use of it in one of the Revelation Space novels, for example).
For the most part, it seems like String/M-Theory is very difficult (at best) to test using technology we have access to at present. But because it includes the idea of gravity being a force which can travel between branes, it's seemed to me and a few friends of mine that this would definitely produce some interesting effects in the real world.
As the article discusses, there should be some subtle evidence of the effects of gravity from external sources on the large-scale structures of our own universe. I would think maybe even enough to at least partly explain "dark matter" and "dark energy", since those are basically the known matter in our universe behaving as if there were a lot more mass that we can't actually see (one set to hold relatively closely-spaced matter together, and the other to accelerate the expansion of the large-scale structures away from each other, if I understand correctly).
A simple flatland-style analogy for "dark energy" might be that our universe is a sheet of paper which is intersected by a universe which is wrapped around into a tube shape or a torus. The gravity of the mass in that second universe pulls objects in our universe toward it, so for the part of our universe in the "eye" of the tube, they tend to accelerate away from each other. That's a vast oversimplification, but I'm not a physicist :).
For "dark matter", the idea that's always stuck with me since reading The Elegant Universe is that maybe some/all of the most massive objects in our own universe - especially the black holes at the centers of galaxies - are caused by the same kind of cross-brane effect. If you have a bunch of matter clumping together in one brane/universe, and it exerts gravity which can cross into other branes, then it seems like it would create corresponding accretions of mass in other nearby branes. Basically, that what we perceive to be a roughly spherical/point object would effectively be the hyperdimensional equivalent of that same shape that would "pin" itself together across branes.
Where I see this as becoming testable (and I could be wrong - again, I'm not a physicist) is that if this were the case, there should be examples of anomalous astrophysical objects and events, where the mass we observe does not line up with effects we also observe. For example, a stable neutron star suddenly flashing into a black hole when it passes too close (hyperdimensionally, of course) to a large mass in another brane. Another example might be a star or planet whose mass can't be reconciled with its observed size - e.g. maybe there is a planet the size of our moon, but which exerts gravity as if it were made entirely out of a material ten times as dense as uranium.
I know that in the context of our own universe/brane, there's no way to pull matter out of a black hole (other than Hawking radiation), but assuming the "hyperdimensional singularity"-type thing I described above is accurate, would it be possible for the cross-brane components to separate (since they wouldn't actually be touching, just exerting gravity on each other)? If so, there might be even stranger observable effects, like neutron stars that "flash" into black holes, but then return to their former state when the mass in the other brane(s) is pulled too far away. IE they would "blink".
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
"Let's be blunt, it's a nasty game" (says The Hitchhikers Guide to the Galaxy), "but then anyone who has been to any of the higher dimensions will know that they're a pretty nasty heathen lot up there who should just be smashed and done in, and would be, too, if anyone could work out a way of firing missiles at right angles to reality."