your thoughts (alternative universes)

[closetgeek]

I have seen a particular program on the Science Channel but I wrote it off as one of those programs made specifically for people like me (interested but not formally educated). Then, last week I read an article which brought it back up. The article discusses new evidence to support the idea of alternate universes. To me it seems that they just rehashed the original evidence which was that particles blink in and out of existence. Parhaps I just don't know enough to understand but it sounds a bit fantastical. I just wanted to get other peoples thoughts on the idea.

[Cougar]

The article discusses new evidence to support the idea of alternate universes. To me it seems that they just rehashed the original evidence which was that particles blink in and out of existence.

I'm not sure how virtual particles can be claimed as evidence of other universes.

There are at least a couple reasons why this multiple universe idea gets tossed around: (1) the so-called fine tuning problem. If the strengths of the physical constants (gravity, fine structure constant, etc.) were very much different, our universe might have collapsed back upon itself very quickly, or it might still be a thin wispy gas with no stars or galaxies. Also called the Goldilocks problem. Occasionally people wonder why our universe happens to be "just right" for the development of lots of stars and galaxies... and living creatures.

One proposed but still speculative answer says, "Well, if there were billions or an infinite number of universes with different configurations, then it makes some sense that at least one will have qualities that are conducive to life, and we happen to be one such universe, obviously. This seems to be largely crafted to avoid the conclusion that we are "special" or "central" or somehow "preferred," which has always led to incorrect conclusions in the past (e.g., the Sun orbits the earth once a day).

(2) Then there are what one might call the new inflationists. There are some very interesting new books out by some of the leading cosmologists who have their own reasons to suggest we live not in a universe, but in a multiverse.

• The Life of the Cosmos [1999] -- Lee Smolin
  
• The Cosmic Landscape, String theory and the illusion of intelligent design [2006] -- Leonard Susskind
  
• Many Worlds in One [2006] -- Alex Vilenkin
  
• Endless Universe, Beyond the Big Bang [2007] -- Paul Steinhardt and Neil Turok

Susskind comes to this conclusion via string theory, which has been found to have not one unique solution, as was sought, but it seems to have 10¹⁵⁰ solutions! Hence the suggestion that there might actually be that many universes.

Vilenkin gets there with a rational analysis of cosmic inflation.

Steinhardt and Turok have a significantly different idea - endlessly cycling universes.

These guys are highly respected in the field, and they are not just throwing out dreamy speculations. These are possible answers with very logical support. However, as far as I know, any hard evidence to support or rule out any of these ideas is currently not available and is likely to be decades away.

[Tim Thompson]

Well, I am not altogether sure what you think "alternate" universes are supposed to be. But I do know that one way to solve various problems in cosmology is to assume that our "universe" is not unique, but rather that it is one of a probably infinite collection of "multiverses". There are a lot of ways to do this (as the linked Wikipedia article shows). But I should think that "evidence" is too strong an idea for multiverses at this point.

The way I see it, "evidence" is of real value when it allows you to distinguish the predictions of one theory from those of another. We can certainly produce multiverse cosmologies which are consistent with the observed properties of our universe, in which case one might argue that the observations are "evidence". But it's not what I would call convincing evidence, or anything even close to that. So far as I know, there is no evidence which allows us to distinguish between "multiverse" and "universe" (i.e., just one universe) cosmologies. I think that kind of evidence would be real news.

[Ken G]

The way I see it, "evidence" is of real value when it allows you to distinguish the predictions of one theory from those of another. We can certainly produce multiverse cosmologies which are consistent with the observed properties of our universe, in which case one might argue that the observations are "evidence". But it's not what I would call convincing evidence, or anything even close to that.

I agree, I think it gets right to the heart of what science is. No doubt the process of doing science has gone through some revisions over the ages, and it is important that we are always clear on just what we are doing and why. I think multiverses (moreso than even string theory) strains the limits of what we can currently call science. So either we will need to redefine science more along the lines of natural philosophy (what I call the "warm fuzzy feeling" approach to the goals of science), or we will need to stick to our guns and say that this stuff just isn't science at all, even though the practitioners are brilliant scientists. In my view they've gone a bit off the deep end, and are looking more for a complete world view rather than simple scientific discovery of how to usefully describe what we observe. That's fine for them, but it does not carry the same mantle of utility of the rest of science, and threatens to blur the currently quite clear lines between science and religion. I would just call it natural philosophy and frame it as "here's the logic, take it or leave it at your own whim". In other words, not at all like the rest of science, which comes as close to objective truth as our intellect is capable of. Even if various multiverse theories make predictions that are falsifiable, chances are the resolutions of those predictions will be far from unique, and likely not so clear how to apply Occam's razor to all the various free parameters available to such theories.

[Noclevername]

As long as there are many possible explanations for virtual particles, they can't be considered evidence of anything. Real evidence would be defined as something that could only be explained by the existence of a multiverse.

[Frog march]

So you think that it's *sigh*ence then Ken G?

[astromark]

The one and only problem with this whole idea of multi or parallel universes is that we simply have no proof of such.
While it might be fine for a fiction writer to imagine what might be or not... In the real world of cold hard facts, there are none.
The word universe describes all of everything as part of that. 'The universe' To imagine more or other is a folly as yet unsupported by any evidence. It is unscientific and foolish to bleat on about this which is just the rantings of those who do not understand what they see so label it wrongly as other universes. When no such proof of existence is or has been found.

[Frog march]

Where is the folly in imagining other universes?

[Noclevername]

There's also no proof that they don't exist. Speculation, as long as it is recognized as speculation and does not violate the facts that we already have strong evidence of, is not folly.

[KaiYeves]

In an alternative universe, would our forum be called TUAB?

[Noclevername]

In an alternative universe, would our forum be called TUAB?

It could be called ISWAATSUT: Incorrect Skywatching And All That Stuff Up There.

[Van Rijn]

I'm not sure what it would be called, but one thing is certain: ToSeek's avatar would not have a goatee, but all others would.

[Noclevername]

I'm not sure what it would be called, but one thing is certain: ToSeek's avatar would not have a goatee, but all others would.

We would all be foaming-at-the-mouth, Luddite CT and ATM promoters...

[TheOncomingStorm]

We would all be foaming-at-the-mouth, Luddite CT and ATM promoters...

In that universe Sibrel would be the bad astonomer.

[KaiYeves]

We would all be foaming-at-the-mouth, Luddite CT and ATM promoters...

I actually wrote a short story called "The Negative Dimension" about that sort of universe. The Mona Lisa is graffiti and graffiti is on display in the Lourve. The Carpathia sank and then the Titanic saved the survivors. "We went to the moon." and "Roswell was a balloon." are crazy, conspiracy theories. The hero ends up joining a demonstration against Global Cooling, then the police come with squirt guns and break it up.
It all turns out to be a dream.

[Noclevername]

In that universe Sibrel would be the bad astonomer.

Shudder.

[Warren Platts]

In my view they've gone a bit off the deep end, and are looking more for a complete world view rather than simple scientific discovery of how to usefully describe what we observe.

Define useful? Megatons of TNT? HDTV? Bovine Growth Hormone?

How about a complete worldview instead? Now that would be useful, ethically at least. Or is it the case that ethics, and I guess you'd say metaphysics, as well as science all float free from each other?

I would say that couldn't be the case. It's just foolish for someone doing ethics, for example, to not take what science has to say seriously. Part of your duty to object X depends on what X is and what X is like--and to whom else is one to turn to besides science when asking such a question?

Of course, science does not entail any particular metaphysical system (cf. Quine's Pursuit of Truth), that I'll heartily grant. It does, however, place constraints on what a true metaphysical system qua complete, theoretical world-view would have to be like: however else such systems may differ, they would all have to be able to reproduce human experience, including the collective scientific experience, in order for them to be plausible.

Sort of like theories about the interior of Jupiter. There's no going there to see 1st-hand what it's like down there. This entails that there are a multitude of more or less equally plausible models that say what it's really like down there. Nevertheless, there are severe constraints on what such models must be like because of scientific observations of Jupiter's mass, the presolar composition, radius, gravitational moments, spectra, and the direct measurements of the Galileo probe, etc.

But then that's just naturalism: naturalism looks only to science as the judge of what there is and what there is is like.

And so it would be useful to know the plausibility of a multiverse versus a this-is-the-onlyverse, because there might be ethical implications at some point under some scenarios, depending on which was really the case.

[Jens]

I actually wrote a short story called "The Negative Dimension" about that sort of universe. The Mona Lisa is graffiti and graffiti is on display in the Lourve. The Carpathia sank and then the Titanic saved the survivors. "We went to the moon." and "Roswell was a balloon." are crazy, conspiracy theories. The hero ends up joining a demonstration against Global Cooling, then the police come with squirt guns and break it up.
It all turns out to be a dream.

It don't sound all that short to me!

[Frog march]

In an alternative maybe all the world would be paper and all the seas might be ink, and if all the trees were bread and cheese; I don't think there would be anything to drink. sadly.

[astromark]

When laid out before you are a collective of the as yet imagined possible explanations for the universe. Or When given options go with the simplest uncomplicated option. It usually is the right choice. Simple is best.
I have watched this subject and others of similar ilk get complicated by all sorts of ethical posturing having scant regard for real scientific evidence or theory. The fact is we have no evidence of other universe or dimension. I do not need to prove to you that no other universe is to be found. I can say it is a folly because I have no fear of being wrong... Its the explanation of what is understood. I am secure in my thoughts as just one universe is all there ever is. However... it must be added that there is no shame in error. I would gladly concede and admit being wrong. just for the proper facts to be presented.

[Frog march]

Did you know, astromark, that the word 'folly' came from the French 'folie'

folie - (psychiatry) a psychological disorder of thought or emotion; a more neutral term than mental illness


(Well that's one definition I found)
which you might think is even more apt. But I still see nothing wrong with speculation; how else would you ever get a paradigm shift?

[Sticks]

I thought parallel universes was a consequence of M-Theory, and that we lived in a giant foam, where the bubbles are universes?

If such an alternate "universe" did exist, what would be the result, if possible of crossing from one reality to another?

Black holes / White holes?

Worm Holes

lethal radiation emitted on both sides?

In terms of fiction, for one forum, in a special "fan fiction" section, I came up with a dimension that was created by human collective unconsciousness where the various mythical creatures from folk fairy tales, Tolkien and ancient deities co-exist. In this land they have politics, wars intrigue etc, with one of the main laws, never to interfere in our world, a law that is occasionally broken. I left it that it was undergoing a civil war between Orcs and Trolls with the other species rooting for the trolls as the Orcs were more into Species-Cleansing.

If an entity wanted to stay in our world they could ony be here a short time unless they had a special device on them.

I may go back to that story line later on, and throw in a gubment organisation tracking incursions from that universe, which was why I wondered what would happen if someone tried to create a bridge between two parallel universes.

BTW does anyone remember that TV show Sliders?

[closetgeek]

Thanks you all for your input. From what I gather of all the replies is that the term "evidence" in this case is used rather loosely, or more to the point, misused. It's not so much the multi-universe part I have difficulty with, it is when they start talking about you or I having existing counter-parts in these alternate universes. The basic mulitiverse idea is just looking at the order of our universes' existance on a grander scale. Similar to the natural explanation of how life exists in our solar system; with so many different possibilities, one is bound to contain life. Wasn't there a time when we were not sure if other solar systems existed? On the other hand, all we needed to prove that there are other solar systems was better equip. Would this whole idea be considered psuedo-science, since there really is no way, at least at this point, to test the predictions? It still is a fun thought to entertain.

Thank you for the list of suggested readings. I definitely will check them out. I am still reading The God Particle and Elegant Universe but they are taking me some time because I have to read it infront of the internet.

[Cougar]

I am still reading The God Particle....

That is a tremendous book. Lederman is a very funny guy! And then he does this:

"We will chronicle the construction of the standard model, which contains all the elementary particles needed to make all the matter in the universe, past or present , plus the forces that act upon these particles."

[Noclevername]

The concept of alternate timelines splitting at discrete events goes back to the late 19th century, maybe further. There are several different theories of other Universe/timelines/planes of existence, call them what you will. Some are considered truly other "universes", i.e., completely separate states of existence. Some may be considered truly "parallel", never touching. Almost all theories agree that sending coherent information between them is not possible, so no interworld travel. Matter just would not survive the trip as matter.

[eburacum45]

Anyone interested in this topic might be interested in Max Tegmark's review of the parallel universe concept
http://arxiv.org/PS_cache/astro-ph/p.../0302131v1.pdf

He identifies four different types-

Level 1: Regions beyond our cosmic horizon (i.e beyond the Hubble Volume); if these regions extend very, very far, they will start to repeat themselves, and an identical version of you will exist at a certain finite (but very large ) distance. A very large number of alternate possibilities would also exist.

Level 2: Other Post-inflation Bubbles; the existence of other Big Bangs, some, many, or most of which will be different in may respects to our own (different rates of inflation, different constants, who knows what).

Level 3: The Many Worlds of Quantum Physics- every event with more than one outcome results in both outcomes existing in parallel- a vast number of events may mean a vast number of universes. David Deutsch has been in the news recently because his team has provided some support to this interpretation;
see
http://www.breitbart.com/article.php...rticle=1&cat=0
but the jury is still out. Perhaps we will never know for sure.

Level 4: Other mathematical structures. Tegmark has completely lost me there- I think he means universes which are so different to ours we can only understand them mathematically.
Well, these universes may exist, but you can't get sandwiches there. Unless there is a universe which is all sandwiches, of course.

[Tim Thompson]

Unless there is a universe which is all sandwiches, of course.

Assuming that the infinity of universes is uncountable, then not only is there a universe that is all sandwiches, but there is an infinity of them! In fact, there must be an infinity of universe which are all PBJ or BLT! Isn't cosmology fun?

[Romanus]

<< In fact, there must be an infinity of universe which are all PBJ or BLT! >>

I just threw up in my mouth a little...



Seriously though, I've always found the concept of alternate universes fascinating. It's a shame though, that if they exist visiting them will probably be even less possible than time travel...

[Noclevername]

Question from a nonphysicist: Why does everyone seem to assume that "infinite (level 3) multiverse" equals "everything you imagine exists somewhere?" Isn't it posssible to have an infinity of something that only consists of one infinite set of possibilities, not all of them?

[eburacum45]

I think that it is true to say that there is an infinite set of universes which don't exist, such as the one that is all sandwiches I mentioned earlier, and the one where Jim Davidson is funny.