Mass of the universe
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Understanding the Mass of the Universe
Total Mass of the Universe: Key Estimates
The mass of the universe has been a subject of extensive research and debate. One of the foundational estimates comes from Eddington, who calculated the mass of the universe to be approximately (2.0 \times 10^{49}) tons, based on the average mass of stars similar to our sun1. This estimate aligns closely with the combined mass of protons and electrons in the universe, which is around (2.55 \times 10^{49}) tons1.
Mass Parameters in Cosmological Theories
Various cosmological theories, despite their differences, converge on a mass parameter of the order of (10^{55}) grams, equivalent to about (10^{79}) protons2. This parameter is fundamental in Eddington's cosmology and appears as a 'fictitious mass' in Milne's theory, suggesting a potential classical mechanics derivation2.
Mass Density and Distribution
The mean mass density of the universe is a critical factor in cosmology. Observations indicate that the mean mass density is about one-third of that predicted by the Einstein–de Sitter model, suggesting either a flaw in conventional galaxy formation theories or the inadequacy of the model itself6. The total mass density, as observed experimentally, is approximately (1.0 \times 10^{-29}) g/cm³, with the total mass of the universe around (10^{53}) kg4.
Dark Matter and Mass Measurement Challenges
A significant portion of the universe's mass is in the form of dark matter, complicating precise measurements. Despite advanced numerical simulations and new methods to determine cosmic mass density from redshift-space distortions, the exact value of the mass density parameter, Ω, remains uncertain by a factor of five7. This uncertainty underscores the complexity of correlating dark matter distribution with observable galaxies7.
Microphysical Arguments and Large Numbers Hypothesis
Microphysical arguments have been used to derive the mass of the universe, linking cosmological parameters with the properties of elementary particles, in line with Dirac's large number hypothesis5. This approach highlights the connection between the macroscopic universe and the microscopic world5.
Conclusion
The mass of the universe is a complex and multifaceted topic, with estimates ranging from (2.0 \times 10^{49}) tons to (10^{53}) kg, depending on the methods and parameters used. While significant progress has been made, particularly in understanding the role of dark matter and the distribution of mass, many uncertainties remain. Future research and advanced methodologies are essential to refine these estimates and enhance our understanding of the universe's mass.
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