This article was originally published in The Conversation. The publication published an article in Expert Voices: Op-Ed & Insights on Space.com.
Whether you need a new villain or an old Spider-Man, your sci-fi movie will sound more scientifically respectable if you use the word “multiverse”. The Marvel Multiverse puts different versions of our universe somewhere “out there”. In these films, with the right combination of technology, magic and imagination, travel between these universes is possible.
For example (spoilers!), in Spider-Man: No Way Home we discover that there are other universes and other Earths, some of which have their own local Spider-Man. Magic is possible in the movie universe.
This magic, thanks to a misguided spell by the superhero Doctor Strange, causes some of the other Spider-Men to be transported into our universe along with several supervillains.
In Doctor Strange in the Multiverse of Madness (in theaters now), universe after universe buffoonery threatens to “desecrate reality.”
So which of these ideas did Marvel borrow from science and which ones are pure fiction?
Multiverse lite: a really big universe
Could there be other Earths? Could there be other people very similar to us on a planet similar to ours? Scientifically, this is possible because we don’t know how big our universe really is.
We can see billions of light-years into space, but we don’t know how much more space there is beyond what we can see.
The more space, full of galaxies, stars and planets, the more and more chances there are for the existence of the Other Earth. Somewhere. With enough space and enough planets, any possibility becomes possible.
The fiction of the Marvel Multiverse stems from the ability to travel between these other lands. There’s a good reason Doctor Strange needs to use magic to do this.
According to Albert Einstein, we cannot travel through space faster than the speed of light. And while more exotic ways of traveling through the universe are scientifically possible—wormholes, for example—we don’t know how to create them, and the universe doesn’t seem to naturally create them, and there’s no reason to think they will. link us to the Other Earth, not some random piece of empty space.
So it’s almost certain that if there is an Other-Earth somewhere, it’s unimaginably far away, even for an astronomer.
(Image credit: Marvel Studios)
Changing the laws of nature
The Marvel Multiverse may seem wild, but scientifically it’s actually a little too tame. Too normal. Too familiar. That’s why.
The basic building blocks of our universe—protons and neutrons (and their quarks), electrons, light, and so on—can do amazing things, like human life. Your body is amazing: it collects energy, processes information, builds mini-machines, regenerates itself.
Physicists have discovered that the ability of the building blocks of our universe to create life forms is extremely rare. Just any old blocks will not work.
If electrons were too heavy or the force holding atomic nuclei together was too weak, the matter of the universe would not even stick together, let alone create something as wonderful as a living cell. Or in general, everything that can be called alive.
How did our universe get the right mix of ingredients? We may have won the space lottery. Perhaps, on scales far beyond what our telescopes can see, other parts of the universe are made up of different building blocks.
Our universe is just one of the options, a particularly good one among multiverses with losing tickets.
This is the scientific multiverse: not just a part of our universe, but universes with other fundamental components. Most of them are dead, but it’s very, very rare that the right combination for life forms appears.
The Marvel Multiverse, by contrast, simply rearranges the familiar atoms and forces of our universe (plus a bit of magic). This is not enough.
(Image credit: IMDB)
Cosmic inflation and the Big Bang
What was our universe like in the past? Evidence suggests that the universe was hotter, denser, and smoother. It’s called the big bang theory.
But was there a Big Bang? Was there a moment when the Universe was infinitely hot, infinitely dense and contained in one point? Okay, maybe. But we’re not sure, so scientists have explored many other options.
One idea, called cosmic inflation, says that in the first fraction of a second, the universe expanded extremely rapidly. If true, it would explain some things about why our universe is expanding the way it does.
But how do you make the universe expand so fast? The answer is a new type of energy field. It controls the first moments of the universe, causes rapid expansion, and then buds more familiar forms of matter and energy: protons, neutrons, electrons, light, etc.
Cosmic inflation could create a multiverse. Here’s how. According to this idea, most of space expands, swells, doubles in size from moment to moment. Spontaneously and randomly, on small islands, a new energy field transforms its energy into ordinary matter with extremely high energies, releasing what we are now seeing as the Big Bang.
If these high energies are confused and reset the basic properties of matter, then each island can be seen as a new universe with different properties. We have made the multiverse.
(Image credit: IMDB)
So does the multiverse exist?
In the scientific method cycle, the multiverse is in an exploratory phase. We have an idea that could explain some things if it were true. This makes it worthy of our attention, but it’s not quite science yet. We need to find evidence that is more direct, more decisive.
Something left over from the aftermath of the multiverse generator could help. The idea of the multiverse could also predict the winning numbers in our lottery ticket.
However, as Doctor Strange explains, “the multiverse is a concept about which we know frighteningly little.”
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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