Mass 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. Eddington's calculations suggest that the universe contains approximately (10^{22}) stars, each with an average mass similar to our sun, leading to a total mass of about (2 \times 10^{49}) tons1. This estimate is corroborated by considering the number of protons and electrons in the universe, which also results in a similar mass calculation1.
Cosmological Theories and Mass Parameters
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 common underlying principle in these models2.
Mass Distribution and Large-Scale Structure
The distribution of mass in the universe is not uniform. Measurements on scales greater than a few kiloparsecs (kpc) reveal significant anisotropies in the background temperature and mass distribution around galaxies3. These observations are crucial for understanding the large-scale structure of the universe and the role of dark matter.
Observable Universe and Dark Energy
The standard cosmological model, Lambda Cold Dark Matter (LCDM), posits an infinite universe with dark energy driving cosmic acceleration. However, an alternative view suggests that the universe has a finite mass, approximately (6 \times 10^{22}) solar masses, and behaves like a black hole with a finite gravitational radius4. This model eliminates the need for dark energy or a cosmological constant, interpreting cosmic acceleration as a measurement of the universe's gravitational radius4.
Mass Fluctuations and Density Parameters
The amplitude of mass fluctuations in the universe, denoted by (\sigma_8), is constrained by the masses and abundances of rich galaxy clusters. For a critical density universe, (\sigma_8) is around 0.52-0.62, while for a spatially flat universe with (\Omega_0 = 0.2), it ranges from 1.25 to 1.585. These values are essential for understanding the distribution of mass and the formation of large-scale structures.
Measuring the Mass of the Cosmos
The mass of the cosmos on gigaparsec scales can be measured using the maximum in the areal radius on the past null cone, which provides a unique geometric reference point6. This method, combined with luminosity and source counts, helps determine the bulk mass-to-light ratio and offers insights into the connection between cosmic geometry and observations6.
Microphysical Derivations and Cosmological Links
Using microphysical arguments, researchers have derived expressions for the universe's mass in terms of fundamental constants and particle parameters, highlighting the link between cosmology and the microscopic world7. This approach aligns with Dirac's large number hypothesis, providing a deeper understanding of the universe's mass.
Estimations and Theoretical Considerations
Estimations of the universe's mass also consider the behavior of test particles under Newtonian mechanics and scalar field theories, incorporating Hubble's law8. These theoretical frameworks offer alternative methods for calculating the universe's mass and understanding its dynamics.
Mass-to-Light Ratios and Dark Matter
The distribution of mass compared to light in the universe reveals that stars trace mass remarkably well, despite representing only a small fraction of the total mass9. Most dark matter is located in the large halos of individual galaxies, and the observed mass-to-light ratio on large scales helps determine the universe's mass density, (\Omega_m), which is approximately 0.269.
Mean Mass Density and Galaxy Clustering
Observations of galaxy clustering indicate that the mean mass density is about one-third of that predicted by the Einstein–de Sitter model10. This discrepancy suggests either a need to revise conventional ideas about galaxy formation or to consider alternative cosmological models10.
Conclusion
The mass of the universe is a complex and multifaceted topic, with estimates ranging from (10^{49}) tons to (10^{55}) grams. Various cosmological theories and observational methods provide different perspectives on this fundamental parameter, highlighting the intricate relationship between mass, structure, and the dynamics of the universe. Understanding the mass distribution and its implications remains a critical area of research in cosmology.
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The Mass of the Universe
The mass of the universe is approximately 2.55 1049 tons, which is close to the weight of the universe calculated on the basis of stars.
Nature and Significance of the Mass Distribution in the Universe
The mass distribution in the universe, measured on scales greater than a few kpc, reveals large-scale anisotropy in background temperature and mean mass distribution around a galaxy.
The mass of our observable Universe
Our universe has a very large but finite regular mass M, which can be interpreted as a measurement of the gravitational radius, rS, with a mass M 6 1022 M.
The amplitude of mass fluctuations in the universe
The amplitude of mass fluctuations in the universe depends strongly on the cosmological density parameter, with a critical density universe having a 8 0.52-0.62 and a spatially flat universe with 0 = 0.2.
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