Astrophysicists from the UK, Australia and the Netherlands have shown through computer simulations that life can be common in the Multiverse. Scientists wanted to estimate how high the likelihood is that in worlds with different values of the density of dark energy, leading to the expansion of space, favorable conditions for life are developing. It turned out that galaxies and stars continue to form in a universe with 300 times stronger dark energy. Two articles of the collective were published in the Monthly Notices of the Royal Astronomical Society (1, 2).
The multiverse is a theoretical concept in cosmology, according to which our universe is just one of a huge number of others. Within the framework of this approach, it is believed that different universes differ in the values of fundamental constants. Because of this, the idea of the Multiverse is considered one of the potential solutions to the problem of fine tuning our world. This problem lies in the fact that astronomers cannot explain with the help of the means of modern theoretical physics many quantities characterizing our Universe, for example, the relationship between the parameters of elementary particles. At the same time, calculations show that even small changes in these ratios individually would make our world at least unsuitable for life.
One of the parameters of the Universe, which can differ for different worlds within the Multiverse, is the density of dark energy. In the modern universe, this substance accounts for about 70% of all energy of all kinds, but physical theories usually predict a much higher percentage. Astrophysicists show in their new works that a significant increase in the strength of dark energy actually only moderately affects the formation of stars and galaxies, since the most important time for the formation of such objects is the early universe, when the share of dark energy in the total amount of matter is small. Consequently, the authors believe, life can exist in a much wider range of universes.
“The multiverse theory has previously claimed to be a lottery explanation of the magnitude of dark energy - we're lucky to live in a universe with beautiful galaxies that could have life,” says co-author Luke Barnes of Western Sydney University in Australia. “Our work shows that we seem to be overly fortunate: our universe is more specific than life needs. This is a problem for the Multiverse as the mystery remains unsolved. Scientists come to the conclusion that if the theory of the Multiverse is correct, then in our world, most likely, dark energy would be 50 times denser than observed. Therefore, the authors call the more likely explanation not this concept, but some still undiscovered natural process.