According to most physicists, the Standard Model of Cosmology depicts how the universe came into existence. Researchers have now looked at the development of galaxies in this model and discovered significant differences from real data.
According to most physicists, the Standard Model of Cosmology depicts how the universe came into existence. The development of galaxies under this model has recently been researched by researchers at the University of Bonn, who discovered significant differences with real data. The study included researchers from the University of St. Andrews in Scotland and Charles University in the Czech Republic. The findings are now available in the Astrophysical Journal.
Most galaxies viewed from Earth have a bulging center and resemble a flat disk. As a result, they resemble the discus thrower’s sporting equipment. However, such disks should only develop seldom, according to the Standard Model of Cosmology. This is because every galaxy in the model is encircled by a halo of dark matter. This halo is invisible, but because to its mass, it has a significant gravitational pull on adjacent galaxies. “That’s why we keep witnessing galaxies merging in the model universe,” says Prof. Dr. Pavel Kroupa of the University of Bonn’s Helmholtz Institute for Radiation and Nuclear Physics.
The scientist adds that the collision has two effects: “First, the galaxies penetrate in the process, breaking the disk form.” Second, it decreases the angular momentum of the newly formed galaxy.” Simply said, this reduces the rotating speed significantly. The centrifugal forces operating during this phase generally induce a new disk to develop due to the spinning motion. A new disk will not develop at all if the angular momentum is sufficiently minimal.
There is a significant difference between what was predicted and what happened
Moritz Haslbauer, a Kroupa PhD student, led an international research group to analyze the development of the cosmos using the newest supercomputer models in the present work. The calculations are based on the Standard Model of Cosmology, and they illustrate which galaxies should have formed by now if the theory is right. The researchers then compared their findings to what is likely the most accurate observational data of the actual Universe observable from Earth at this time.
“We found a major gap between forecast and reality here,” Haslbauer says: “There seem to be much more flat disk galaxies than theory can explain.” Even with today’s supercomputers, however, simulation resolution is restricted. As a result, it’s possible that the number of disk galaxies formed in the Standard Model of Cosmology has been underestimated. “However, even after accounting for this impact, there remains a significant gap between theory and reality that cannot be bridged,” Haslbauer says.
The scenario is different in the case of a dark matter-free alternative to the Standard Model. Galaxies do not develop by merging with one other, according to the MOND hypothesis (the abbreviation stands for “MilgrOmiaN Dynamics”). Instead, they’re made up of revolving gas clouds that are gradually condensing. Galaxies develop in a MOND universe by absorbing gas from their surrounds. In MOND, however, full-grown galaxies seldom fuse. “Our research group in Bonn and Prague has established the means for doing calculations in this alternative theory,” says Kroupa, who is also a member of the University of Bonn’s Transdisciplinary Research Units “Modelling” and “Matter.” “MOND’s projections are in line with what we’re seeing.”
The Standard Model faces a challenge
Even with MOND, however, the specific mechanics of galaxy development are still unknown. Furthermore, in MOND, Newton’s laws of gravity do not apply in some situations and must be substituted with the proper ones. This would have far-reaching implications in other fields of physics. Despite being initially created to address galaxies solely, the MOND theory answers all known extragalactic cosmological difficulties, according to Dr. Indranil Banik, who was engaged in this study. “Our research shows that today’s young physicists may still make substantial contributions to basic physics,” Kroupa says.
