Where is most of the baryonic matter of the universe found
Most of the baryonic matter in the universe is found in the form of hot, ionized gas in galaxy clusters and superclusters. These large-scale structures contain multiple galaxies bound together by gravity, and the space between the galaxies is filled with diffuse gas known as the intracluster medium (ICM). The ICM is primarily composed of hydrogen and helium, along with trace amounts of other elements. This hot gas can be detected through its X-ray emission, and it makes up a significant portion of the baryonic matter in the universe.
Most of the baryonic matter in the universe is found in galaxies. Galaxies are large systems consisting of stars, gas, dust, and dark matter. Within galaxies, most of the baryonic matter is located in the form of stars, which make up a significant portion of the mass. Additionally, interstellar gas and dust contribute to the total baryonic matter. Dark matter, although not made up of baryons, also plays a major role in the mass of galaxies. It is estimated that baryonic matter accounts for only about 5% of the total mass-energy content of the universe, with dark matter making up around 27%. The remaining 68% is attributed to dark energy, a mysterious form of energy that drives the accelerated expansion of the universe.
Most of the baryonic matter in the universe is found in large-scale structures such as galaxy clusters, galaxies, and intergalactic gas. To determine where most of the baryonic matter is located in the universe, scientists rely on observational data and theoretical models. Here's how they figure it out:
1. Observational Data: Astronomers use various telescopes and instruments to observe different regions of the universe in different wavelengths of light (such as visible, infrared, X-ray, etc.). These observations provide valuable insights into the distribution of matter.
2. Galaxy Surveys: Large-scale surveys of galaxies help map out the distribution of visible matter. By counting and categorizing millions of galaxies, scientists can estimate the overall density of baryonic matter in the universe.
3. Gravitational Lensing: The gravitational lensing effect occurs when the gravitational field of a massive object (such as a galaxy cluster) bends the path of light from more distant objects. By studying this distortion of light, astronomers can indirectly infer the presence and distribution of matter, including invisible dark matter.
4. Cosmic Microwave Background (CMB): The CMB is the residual radiation from the early universe, considered the oldest light we can observe. Precise measurements of its temperature and fluctuations provide information about the density variations in the early universe and the formation of large-scale structures.
Combining data from these different sources, scientists have concluded that the majority of baryonic matter is found in galaxy clusters and galaxies. These structures are held together by gravity and act as reservoirs of baryonic matter, including stars, gas, and dust. However, it's important to note that even though baryonic matter is the ordinary matter we are familiar with, it only accounts for about 5% of the total energy density of the universe. The remaining percentage is made up of dark matter (about 27%) and dark energy (about 68%), both of which have different properties and cannot be directly observed.