The multiverse may be the biggest topic of discussion possible, since it covers every imaginable possible reality and ones never imagined up to now. Though the topic of God may be bigger, depending on a person’s view of God. (Though I’ll strive to give just one chewable bite of multiverse for today. 🙂 )
We arrived here at this topic because we mentioned last time that the force of dark energy is far, far less than quantum mechanics predicts that it should be. By the way, I made an error last week in that I said the difference between measured and predicted concerning dark energy is on the order of 10 to the 20th power. I wrote out all the zeros–but I should have said 10 to the 120th power (10^120)–so please add one hundred more zeros to the figure I used last week, OK? 🙂
The existence of a massive amount of potential energy in vacuum on the quantum level (according to quantum mechanics as currently understood) suggests to scientists that what’s happening with dark energy is that quantum forces must be manifesting energy at both positive and negative levels, which nearly but not completely cancel each other out. Since there is no known means to explain how these quantum forces would engage in such a precise dance that lets some of the energy come through while most self-obliterates, some scientists pull out the concept of the “multiverse” to explain it.
The reasoning goes something like this: Believing that the universe could be deliberately fine-tuned between opposing forces in a way that strongly implies the universe is not a random, unintentional event–that position is ruled out, looked down on, seen as crazy talk. No, according to the modern scientific bias/paradigm, the universe should not show any “fine tuning” and any apparent fine tuning is something to explain away.
So, they imagine that there is a massive number of universes, even though there is no direct evidence they exist, even greater in number than 10^120. One figure linked to String Theory has 10^500 possible configurations of the multiverse and imagines that each one actually exists somewhere. So, in just one out of the colossal horde of possible universes, we happen to be living in the one where vacuum energy nearly balances out to explain the dark energy that’s believed to exist. (By the way, to get a grasp on how big these numbers are, please note that there are “only” around 10^83 atoms estimated in the entire observable universe.)
This “lucky winner” universe would not only explain the supposedly observed dark energy as coming from one universe that happened to randomly work out, it would also explain how the constants of particle physics (in the Standard Model) are what they are. They also are lucky winners. (These constants were discussed in part 4 of this series).
How did our universe in this multiverse get so lucky? I mean, this is much luckier than winning the lottery, which “only” requires 1 chance in 10^8 (1 in 1,000,000) or so.
Well, the “luck” comes via the anthropic principle (technically the “weak anthropic principle”) that means that a universe which didn’t have the right setup for life would never have generated intelligent beings like you and I in the first place, who are capable of knowing how unusual the universe is. Likewise, all the versions of reality that are totally hostile to life may exist, but they don’t have any intelligent beings living inside them to notice that they do exist. Or how messed up they are.
Note that there is more than one concept of a multiverse–this post is only discussing one such idea. Please also note that some scientists dislike the idea of a multiverse, since there is no direct evidence for it. And there are also those not keen on using the anthropic principle to explain away the improbabilities evident in the universe forming itself (they hope to find new physics to explain the improbabilities instead).
But for many cosmologists, multiverse + anthropic principle = an answer to the wild improbabilities required to generate the universe that we observe. In a later post in this series I’ll show how this mindset creates serious problems with believing in a real, physical universe. But for now, let the reader of this post be aware of how the idea of the multivese and the anthropic principle are often used together.
Perhaps instead of complaining that the concept of a God with a purpose and a plan is inherently simpler (in my opinion) than the idea of a near-infinite array of random multiverses, I should be thankful. As a writer of speculative fiction, the concept of a multiverse provides copious opportunities to create new stories.
To name only a few examples of the multiverse in Speculative Fiction, C.S. Lewis wrote his “wood between the words” of multiverses even before the idea became widely accepted among theoretical physicists. Various Star Trek series had episodes from an alternate universe where instead of building the Federation, humanity built an empire and the 2009 Star Trek movie rebooted the movie series with stories entirely different from those before, due to the use of multiverse ideas. Stephen King likewise waded into the vast array of universes imagined to exist with his Dark Tower books and other stories like The Mist. And the recent Netflix program Stranger Things explores the idea of creatures from an alternate universe (The Upside Down) crossing over into our own.
While multiverse ideas are quite a lot of fun, I would say if there really are multiple universes, instead of the multiverse making all that we know of come about for essentially random reasons, each alternate universe would have to be as much created by God as the one we inhabit.
But what are your thoughts on this topic?
Do you think the multiverse is likely? Do you believe scientists should avoid talking about it–that this is more philosophy than science?
What is your favorite multiverse or alternate world speculative fiction story?