What is the composition of the universe
Pro Research Analysisby 
Searched over 200M research papers
Composition of the Universe
Overview of Universe Composition: 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 and cosmic microwave background radiation. Baryonic matter, which makes up stars, planets, and all visible structures, constitutes only a small fraction of the universe's total mass-energy content .
Dark Matter: The Invisible Mass
Dark matter is a critical component of the universe, accounting for approximately 26.8% of its total mass-energy content. Unlike baryonic matter, dark matter does not emit or absorb light, making it invisible and detectable only through its gravitational effects on visible matter and radiation . Dark matter plays a crucial role in the formation and evolution of cosmic structures, such as galaxies and galaxy clusters, by providing the necessary gravitational pull to hold these structures together Springel2006Turner1991.
Dark Energy: The Mysterious Force Driving Expansion
Dark energy is an even more enigmatic component, making up about 68.3% of the universe's total mass-energy content. It is responsible for the accelerated expansion of the universe, a phenomenon first observed in the late 20th century. The nature of dark energy remains one of the most significant unsolved problems in physics, with various theories suggesting it could be a property of space itself or a new dynamic field Seife2005Mullat2015.
Baryonic Matter: The Ordinary Matter
Baryonic matter, which includes protons, neutrons, and electrons, constitutes only about 4.9% of the universe's total mass-energy content. This ordinary matter forms the stars, planets, and all other visible structures in the universe. Despite its relatively small contribution to the overall mass-energy budget, baryonic matter is essential for the formation of complex structures and life as we know it John2021Mullat2015.
Radiation: The Energy of Light
Radiation, though a minor component in terms of mass-energy content, plays a significant role in the universe. It includes all forms of electromagnetic waves, from visible light to cosmic microwave background radiation, which provides crucial information about the early universe and its subsequent evolution .
The Role of Cosmic Voids
Cosmic voids, large and relatively empty regions of space, also contribute to our understanding of the universe's composition. These voids are surrounded by matter, both dark and luminous, which is attracted to their boundaries. The study of voids helps constrain the average matter content of the universe and provides insights into the dynamics of cosmic structures .
Conclusion
The universe is a complex and dynamic entity composed of radiation, baryonic matter, dark matter, and dark energy. While baryonic matter forms the visible structures, dark matter and dark energy dominate the universe's mass-energy content, driving its expansion and shaping its large-scale structure. Understanding these components and their interactions remains a central challenge in cosmology, with ongoing research continually refining our knowledge of the universe's composition.
Sources and full results
Most relevant research papers on this topic
A Posteriori Speculations using Current Mass-Energy Composition of the Universe
The Planck Mission's mass-energy composition equation accurately confirms the universe's composition, with 26.8% dark matter, 68.3% dark energy, and 4.9% ordinary matter.
A Physico-Chemical Approach To Understanding Cosmic Evolution: Thermodynamics Of Expansion And Composition Of The Universe
The expansion of the universe accelerated due to dark energy at 7.25 x 109 years, and dark matter is identified as a plasma form of matter similar to that which existed before recombination and during reionization.
DOI