Theorists have shown that weak interaction is not necessary for the Universe to remain stable, stars shine in it, planets and even life appear in it.
All the variety of particle interactions in our world is reduced to the action of four fundamental forces: gravity and electromagnetism, as well as strong nuclear interaction (thanks to which the nuclei of atoms remain stable) and weak (which is responsible for radioactive decay and the conversion of neutrons into protons, electrons and neutrinos). And if the hypothesis of the existence of countless universes is true, in which other laws of physics may operate, then other worlds may well be devoid of one or another kind of fundamental forces.
Calculations show that far from all such universes will be stable, far from all stable worlds will be able to give birth to stars, etc. - the physics of our world can be an extremely rare, or even unique case, the structure of which ultimately allows life to appear and develop in her. However, recent theoretical work shows that weak interactions can be considered optional for this.
Back in 2006, Stanford physicists showed that a Universe devoid of weak strength could well exist and remain fairly stable. The authors of a new article, presented in the arXiv.org online preprint library, conclude that such a world can even produce stars, heavy elements, and in the long term - life.
Fred Adams and his colleagues at the University of Michigan simulated the Big Bang and the birth of a universe devoid of weak nuclear forces. Thanks to him, our own world consists mainly of protons, hydrogen nuclei that are left after the beta decay of neutrons. In the depths of stars, they enter into thermonuclear reactions, forming more and more heavier elements that are carried throughout the Universe and fill it with material to form new stars, planets and - ultimately, you and me.
However, in a universe where there is no weak interaction, neutrons will accumulate without decaying. In such a world there should be a deficiency of heavy elements, but it can exist, and, apparently, can even support life. Simulations carried out by Adams and his co-authors showed that for this it is only necessary to slightly correct the initial conditions for the emergence of the Universe, so that it starts with fewer neutrons and more free protons than ours.
In this case, they can recombine with the formation of nuclei of deuterium, heavy hydrogen. It can also participate in thermonuclear transformations, and its reactions release more energy, so the stars of this world should be hotter and brighter than ours. Nevertheless, they are quite capable of producing the entire range of heavy elements, including iron, and carrying them with the stellar wind through space.
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Of course, both the water and the minerals of the planets, which are formed with the inclusion of deuterium, will slightly differ in properties from our "analogues". Living beings from our Universe are unlikely to be able to survive there, but if life evolved in the world itself, filled with neutrons and devoid of weak interaction, it must be adapted to these strange - for us - conditions.
Sergey Vasiliev