Why We Think There's a Multiverse, Not Just Our Universe

An anonymous reader writes "It's generally accepted that the Universe's history is best described by the Big Bang model, with General Relativity and Quantum Field Theory as the physical laws governing the underlying framework. It's also accepted that the Universe probably started off with an early period of cosmic inflation prior to that. Well, if you accept those things — as in, the standard picture of the Universe — then a multiverse is an inevitable consequence of the physics of the early Universe, and this article explains why that's the case."

Comments

So it's turtles all the way across.

[gestalt_n_pepper]

But the turtles appear out of nowhere and are very far apart.
Why do cosmological theories of any merit always sound like they were written by Douglas Adams?

Can we just call it a "partitioned universe"

[Anonymous Coward]

or something less stupid, instead?

It doesn't make any sense to say that it's one big thing, but not one big thing at the same time.

Kind of like saying it's not one big cake sliced into wedges, it's lots of little cakes that have nothing to do with each other.

AND YET THEY OCCUPY THE SAME PLATTER.

Re:Can we just call it a "partitioned universe"

[zAPPzAPP]

The problem lies in the name 'UNIverse'.
You can not name something universe and then have something next to it.

My God...

[jeffb (2.718)]

I know it's karma suicide to post on something like this saying "I don't get it", but, well, I don't get it.

I've been reading about inflation, multiverses, and whatnot for a very long time at this point, and I like to think that I can give a reasonable explanation comprehensible to nontechnical people. I've come across some articles that were a lot of work to get through, and I've given up on some because I don't have the necessary math.

But this article was terrible. Its grammar is good and not overly complex; it doesn't use a lot of obscure words. It's written like a nice popularization piece, with important parts called out in bold and lots of illustrations. But the illustrations are baffling -- what's that "getting closer to a sphere" four-panel diagram credited to Ned Wright, and where does the text refer to it? What the heck is going on with those diagrams from Narlikar and Padmanabhan? What's with the black space-balls rolling around on the mini-golf course at the end?

I'd wonder if this is a Sokol-type troll, but I don't see anything obviously wrong in it -- there's just a bunch of stuff there that looks like explanations, but apparently isn't. Or maybe I'm just having a bad night.

Re:My God...

[JoshuaZ]

There are tests for inflation. Depending on the version of inflation in question one can get different predictions, but one major issue is how close to flat the universe is. Another major aspect is the exact behavior of the cosmic microwave background. Study of these issues are both ongoing.

Re:My God...

[smpoole7]

> Is this testable?

I spent a good bit of time trying to explain this to laycreatures at my own Website. Karl Popper pretty well summed up the rules for scientific theories:

1. It must adequately explain that which is known about the thing being observed.
2. It must be falsifiable. In other words, it must make concrete predictions that can be tested empirically. If not, it is NOT a scientific theory.
3. This is the key: the SIMPLEST (i.e., the most "economical") theory that adequately explains the observations is preferred.

This is extremely important: just because you come up with a theory that seems to work does NOT mean that you're right. It simply means that you've found a mathematical model that works as far as you are able to understand and test it.

These guys seem to believe that inflation compels a belief in multiverses. They are certainly not alone in that. But in the interest of equal time, there are PLENTY of other cosmological-types who insist that there are alternate explanations. The "math" does NOT lead only and exclusively to that conclusion. In fact, while researching this for my Website, I found a flooding TON of physicists who went all the way back to Andre Linde (who was one of the first to popularize this) and beyond, and poked all sorts of holes in these arguments.

Disclaimer, I'm not a physicist and don't claim to be. But I'm about as up to speed on it as a layman can get and still remain sane. :)

Re:Words, words

[Derec01]

I disagree that he's only defined causally disconnected regions; this story actually has a definition of multiverse beyond regions outside of our lightcone. Note one of his later images: a single level 1 universe contained multiple regions which are not causally connected yet are part of the same clump that moved from the false vacuum to dumping energy into matter and radiation.

Any grouping like that is fundamentally isolated because the boundary region that remains in the false vacuum continues to exponentially expand, quickly isolating the clump. Even if the clump itself triggers a conversion of the false vacuum around it, it sounds like the isolation proceeds so much faster that it will be forever isolated by expanding false vacuum regions. With time, we could reach places that are not currently causally connected. It doesn't sound like we could overcome this expansion so easily.

Re: You mean

[Alsee]

They won't suck like our current politicians.
They will suck in interesting new ways.

-

Re: You mean

[Concerned Onlooker]

"Give me a phone book and a week and I'll improve on every nationally elected official just picking names at randomâ¦"

You don't need a whole week.

Sociopaths rise to the top disproportionately (politicians and other power seeking people). Sociopaths make up about 3-5% of the population. Picking 10 names at random (forget even asking them any questions) would statistically get you at the very least a more decent set of human beings.

Re: You mean

[Sardaukar86]

Sociopaths rise to the top disproportionately (politicians and other power seeking people)

You're quite correct. It's a phenomenon almost akin to some sort of natural law:

“Society is like a stew. If you don’t keep it stirred up, you get a lot of scum on top.”
Edward Abbey

It seems to me that we have the vote as our only real method of agitation. No surprise then, that our vote matters less and less as society marches on.