The composition of the universe
Pro Research Analysisby 
Searched over 200M research papers
The Composition of the Universe
Components of the Universe: Radiation, Baryonic Matter, Dark Matter, and Dark Energy
The universe is composed of four primary components: radiation, baryonic (ordinary) matter, dark matter, and dark energy. Radiation includes all forms of electromagnetic waves, such as light. Baryonic matter, which makes up stars, planets, and all visible structures, constitutes only a small fraction of the universe's total mass. Dark matter, an invisible substance that does not emit or absorb light, forms the majority of the universe's mass. Dark energy, a mysterious force, is responsible for the accelerated expansion of the universe 12.
Dark Matter and Dark Energy: The Dominant Forces
Independent measurements indicate that ordinary matter makes up only about 30% of the universe's total content. The remaining 70% is attributed to dark energy, which acts as an antigravity force driving the universe's accelerated expansion . Dark matter, although invisible, plays a crucial role in the formation and evolution of cosmic structures. It provides the gravitational framework within which galaxies and other structures form and evolve 35.
The Evolution of Cosmic Structures
The large-scale structure of the universe, including galaxies and clusters, originated from tiny ripples in the early universe. Over 14 billion years, these ripples were amplified by gravitational forces, leading to the formation of dense regions of dark matter where ordinary matter could cool and condense to form galaxies. This process has been extensively studied through computer simulations and observational data .
The Role of Exotic Matter and Theories of Cosmic Evolution
Recent models suggest that a combination of exotic matter, dust, and dark energy could explain the observed properties of the universe. These models are tested against observational data, such as the Hubble parameter and redshift measurements, to constrain their parameters and validate their predictions . Additionally, thermodynamic approaches have been used to understand the universe's expansion and composition, correlating dark energy with the energy of space and identifying dark matter as a plasma form of matter .
Observational Constraints and Theoretical Models
Observations from missions like Planck have provided precise measurements of the universe's composition: approximately 26.8% dark matter, 68.3% dark energy, and 4.9% ordinary matter. These measurements align closely with theoretical models, confirming our understanding of the universe's mass-energy distribution . Studies of cosmic voids, large empty regions in the universe, further constrain the average matter content and the growth rate of cosmic structures, providing robust tests for cosmological models .
Conclusion
The composition of the universe is a complex interplay of radiation, baryonic matter, dark matter, and dark energy. While ordinary matter forms the visible structures, dark matter and dark energy dominate the universe's mass and drive its expansion. Ongoing research and observations continue to refine our understanding of these components and their roles in cosmic evolution.
Sources and full results
Most relevant research papers on this topic