You’ve read about them in sci-fi novels, seen them in sci-fi movies, and virtually entered them through sci-fi video games, but is there any way multiverses could be more science than fiction?
There could be. Science News recently unearthed a study that suggests a theoretical possibility for an alternate universe (or universes) where there could even be life, if you just deleted one of the four fundamental forces that rule this one.
Gravity keeps us from flying everywhere randomly, and our bodies are designed to thrive in Earth’s gravity, which is why NASA has to keep running so many tests on how human bodies react to microgravity before an extended mission to Mars or beyond. Turn that gravity up and we’d be flattened at best and collapse into black holes at worst. Another thing keeping us together is strong nuclear force. You can’t possibly expect something to stay in one piece if its atomic nuclei scatter all over the place. Electromagnetic force lets there be light.
Weak nuclear force is that fourth wild card. This force is the reason neutrons decay into protons, and theoretical physicist Fred Adams and colleagues believe a hypothetical universe could survive without it (emphasis on “hypothetical” here).
“Without weak interactions, neutrons no longer decay, and the universe emerges from its early epochs with a mixture of protons, neutrons, deuterium, and helium,” said the scientists, who simulated how astrophysical processes like the Big Bang and star formation would play out differently sans weak force.
At least in our universe, which is mostly hydrogen, the absence of neutron decay would also cancel out the existence of heavier elements. Hydrogen atoms contain a single proton and electron. Heat in the scorching cores of stars fuses these protons, which are fused into heavier elements that are then flung out into space and merge to create objects like asteroids and planets. Everything floating around in this universe is there because of that proton fusion—meaning if it hadn’t happened, we wouldn’t exist.
That doesn’t mean something else may not exist in a weak-force-less universe.
“People talk about universes like they’re very fine-tuned; if you changed things just a little bit, life would die,” Adams told Science News, but he believes “the universe and stars have a lot more pathways to success.”
A universe without weak force would have to have emerged from the vacuum of space with more free protons and fewer neutrons than our universe had at birth. These neutrons and protons would bond into efficiently burning hydrogen isotope deuterium, which would fuel enormous reddish stars that blazed with more heat than those that shine in this night sky. Every element up to iron could be created in the cores of these stars until stellar winds scattered those elements into the vast expanse of the cosmos.
There’s just one thing. Deuterium would kill life as we know it. However, that wouldn’t be a problem for organisms that evolved in deuterium-infused water. Maybe oxygen would be toxic to them.
Whether this multiverse actually exists is a whole other question to keep you up at night, but it could be the next sci-fi movie smash.
(via Science News)