The strongest limit on the number of possible universes is the human ability to distinguish between different universes. Posted on 10/18/2009 4:06:14 AM PDT by LibWhacker
The strongest limit on the number of possible universes is the human ability to distinguish between different universes.
(PhysOrg.com) -- Over the past few decades, the idea that our universe could be one of many alternate universes within a giant multiverse has grown from a sci-fi fantasy into a legitimate theoretical possibility. Several theories of physics and astronomy have hypothesized the existence of a multiverse made of many parallel universes. One obvious question that arises, then, is exactly how many of these parallel universes might there be.
In a new study, Stanford physicists Andrei Linde and Vitaly Vanchurin have calculated the number of all possible universes, coming up with an answer of 10^10^16. If that number sounds large, the scientists explain that it would have been even more humongous, except that we observers are limited in our ability to distinguish more universes; otherwise, there could be as many as 10^10^10^7 universes.
To work these numbers out, Linde and Vanchurin looked back to the time shortly after the Big Bang, which they view as a quantum process that generated lots of quantum fluctuations. Then during the period of inflation, the universe grew rapidly and these quantum fluctuations were "frozen" into classical perturbations in distinct regions. Today, each of these regions could be a different universe, having its own distinct laws of low energy physics.
By analyzing the mechanism (called "slow roll inflation") that initially generated the quantum fluctuations, the scientists could estimate the number of resulting universes at 10^10^10^7 (a number which is dependent on the model they used). However, this number is limited by other factors, specifically by the limits of the human brain. Since the total amount of information that one individual can absorb in a lifetime is about 10^16 bits, which is equivalent to 10^10^16 configurations, this means that a human brain couldn't distinguish more than 10^10^16 universes.
Requiring that the human brain must be able to count the number of parallel universes may seem inappropriate, if not arrogant, but Linde and Vanchurin explain that dealing with the quantum world is different than our everyday lives in which quantum effects can be safely ignored. A crucial part of their calculation here is an investigation of quantum effects on supergalactic scales. In this kind of scenario, the state of the multiverse and observations made by an observer are correlated (similar to the Schrodinger cat experiment, where the outcome can be determined only after it is registered by a classical observer).
"When we analyze the probability of the existence of a universe of a given type, we should be talking about a consistent pair: the universe and an observer who makes the rest of the universe 'alive' and the wave function of the rest of the universe time-dependent," the scientists write.
As the scientists explain, the calculation of the number of universes is an important step toward an even larger goal: to find the probability of living in a universe with a particular set of properties. What are the chances that we live in a world in which the laws of physics are these laws that we currently observe? Answering this question requires finding probabilities that depend on knowing about other universes, among many other challenges.
Forgive me for asking, but if the “universe” consists of all matter, energy, and space that exist, how can there be a “parallel universe”? Wouldn’t it be more accurate to say they believe there are parts of the universe that have not yet been discovered?No. The generally accepted use of the term "universe" is "all the matter and energy in this Big Bang". It's everything we can see and measure and trace it's origin back to "the" Big Bang.
Other universes -- other Big Bangs -- are not observable and are outside our "universe".
The whole collective of universes (whether "parallel universes" or "alternate Big Bangs in an Eternal Inflation") are described as the Multiverse (or, by Guth, as the Cosmos).
I’m guessing that was September 1958... is that right?
There is another alternative universe out there in which everything happened exactly the same since the beginning of time except that I did not respond to this post.
Now you're really getting into sci-fi territory.
1. A number of the theories used to explain the apparent conflict between relativity and quantum mechanics depend on the "other universe" or "hidden dimensions" theories. It is possible to make predictions based on these theories whereby the not observable things would affect things we can observe. Experiments could potentially prove or disprove these predictions.
2. Some have proposed that at very high speeds or gravitational levels (black holes) it might be possible to "turn sideways" and pass into another universe or at least be able to observe it or its effects.
I have no idea whether any of this is possible. I'm just leary of using the terms "always" and "never" when talking about possible future science.
Best critique of these guys I’ve seen.
I can’t afford to live in a parallel universe. All I can afford is a parallel zip code.
They have a Famous Rays there too!
I used to think there were an infinite number of alternative universes. Thus everything that can happen does happen and, furthermore, happens an infinite number of times. However, with this rather small limit of 10^10^16, not everything can happen and certainly not an infinite number of times. So I might not be in clover anywhere. This may be as good as it gets. :-(
We need to find a way to travel to other universes.
Just move all of the decent folk to a Universe where humans never existed and leave the socialists and islamists to each other throats.
If crazies ever arise in the new universe send them back “Home”.
Plus the alternate earth will have vast untapped deposits of oil and minerals and no indigenous folks there so the liberal attitude of “blame America for the rest of the world’s suffering” would never exist there.
Sounds like Paradise! I am sure God would want us to develop “Sliding Technology”
We could move Israel (Whole country and infrastructure including 10ft of topsoil so they have the holy land in the new universe)into a the same world or another one as then they wouldn’t have to deal withe crazy nutbags in the Middle east.
Mazeltoff!
(Of course this Multiple Universe stuff sounds like something off of Fringe)
I mean, when the universe splits, we personally branch off too. A copy of us goes down the good branch and a copy goes down the crappy branch. Why does this particular consciousness that is me always go down the crappy branch where, for instance, we were defiled with knowledge of the Clintons, Iran ended up with nukes and a Kenyan became president? That's a gross simplification, of course, but you get the idea.
No sirree, it's time for us to seize the bull by the horns and only steer ourselves down happy branches from here on, all the way to Utopia. No more rallies. No more voting. I'm just gonna take a short cut.
Heh — good pic!
(Larry, you are up late tonight!)
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