- "Dark matter is a hypothetical form of matter thought to be the predominant type of matter in the universe."
Unidentified matter that constitutes around 27% of the mass-energy of the Universe and is responsible for the observed gravitational lensing and structure formation.
Dark matter: A hypothetical form of matter that is believed to exist because of its gravitational effects on visible matter in the universe.
Cosmology: The study of the origin, evolution, structure, and ultimate fate of the universe.
Observational evidence of dark matter: Evidence for dark matter such as the rotation curves of galaxies and gravitational lensing.
Non-baryonic dark matter: Dark matter that is not composed of baryons (protons and neutrons).
WIMP theory: Weakly interacting massive particles that are proposed as one form of dark matter.
Axion theory: Hypothetical particles that are proposed as another form of dark matter.
Detection methods: Methods used to detect dark matter, such as direct and indirect detection.
Dark matter halo: The hypothetical distribution of dark matter around a galaxy.
Dark matter density profile: The distribution of dark matter within a galaxy or cluster of galaxies.
Dark matter simulation: Simulations used to study the distribution and evolution of dark matter in the universe.
Dark energy: Another enigmatic component of the universe believed to be causing the observed accelerating expansion of the universe.
Modified gravity theories: Alternative theories that seek to explain the observed phenomena without the need for dark matter or dark energy.
Big Bang nucleosynthesis: The theory that explains the formation of light elements such as helium and deuterium in the early universe.
Cosmic microwave background radiation: The radiation left over from the Big Bang, which has been used to study the composition and evolution of the universe.
Large Scale Structure: The study of the distribution of matter in the universe on very large scales.
Inflation: The period of exponential expansion of the universe that is believed to have occurred in the first fractions of a second after the Big Bang, which has been invoked to explain several puzzles in cosmology.
Accelerated expansion: The observed accelerated expansion of the universe, which has been attributed to the presence of dark energy.
Galactic dynamics: The study of the motions of stars and gas in galaxies, which provides evidence for the presence of dark matter.
Strong gravitational lensing: The bending of light due to the gravitational field of a massive object such as a galaxy, which has been used to study the distribution of dark matter.
Cosmic structure formation: The process by which the large-scale structure of the universe formed, which is influenced by the presence of dark matter.
Cold dark matter (CDM): This is the most widely accepted type of dark matter. It is made up of massive particles that move slowly or "coldly" through space.
Warm dark matter (WDM): This type of dark matter is made up of particles that move faster than those in CDM, but slower than those in hot dark matter.
Hot dark matter (HDM): This is made up of very light, fast-moving particles, such as neutrinos.
Slow-moving axions: These particles are theorized to exist and are predicted to have low mass and low interaction with other particles.
Sterile neutrinos: These are often referred to as "ghost particles" and have been mentioned as a possible source of dark matter. They do not interact with light or electromagnetically charged particles.
Gravitinos: These are hypothetical particles that are predicted by supergravity theory and could account for dark matter, they are similar to neutrinos, but more massive.
Hidden valley dark matter: This is a theoretical model that proposes that dark matter is made up of a type of matter that interacts only weakly with normal matter.
WIMP (Weakly Interacting Massive Particle): This is a type of cold dark matter particle that is hypothesized to have a mass similar to that of a proton and interact primarily through the weak nuclear force.
SIMP (Strongly Interacting Massive Particle): This hypothetical particle could be a form of dark matter that interacts strongly with itself but weakly with other particles.
- "It is called 'dark' because it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect, or emit electromagnetic radiation and is, therefore, difficult to detect."
- "Its existence is implied by various astrophysical observations which cannot be explained by general relativity unless more matter is present than can be seen."
- "Evidence for dark matter comes from many different angles, such as galaxy dynamics and formation, gravitational lensing, and the cosmic microwave background, along with astronomical observations of the observable universe's current structure, the formation and evolution of galaxies, mass location during galactic collisions, and the motion of galaxies within galaxy clusters."
- "In the standard Lambda-CDM model of cosmology, the total mass–energy content of the universe contains 5% ordinary matter, 26.8% dark matter, and 68.2% of a form of energy known as dark energy."
- "Dark matter constitutes 85% of the total mass, while dark energy and dark matter constitute 95% of the total mass–energy content."
- "Its existence is not known to interact with ordinary baryonic matter and radiation except through gravity, making it difficult to detect in the laboratory."
- "The leading explanation is that dark matter is some as-yet-undiscovered subatomic particle, such as weakly interacting massive particles (WIMPs) or axions."
- "The other main possibility is that dark matter is composed of primordial black holes."
- "Many experiments to detect and study dark matter particles directly are being actively undertaken, but none have yet succeeded."
- "Dark matter is classified as 'cold', 'warm', or 'hot' according to its velocity (more precisely, its free streaming length)."
- "Recent models favored a cold dark matter scenario, in which structures emerge by the gradual accumulation of particles."
- "Recent gravitational wave and James Webb Space Telescope observations have considerably strengthened the case for primordial and direct collapse black holes."
- "Although the astrophysics community generally accepts dark matter's existence, a minority of astrophysicists, intrigued by specific observations that are not well-explained by ordinary dark matter, argue for various modifications of the standard laws of general relativity."
- "These include modified Newtonian dynamics, tensor–vector–scalar gravity, or entropic gravity."
- "So far, none of the proposed modified gravity theories can successfully describe every piece of observational evidence at the same time."
- "suggesting that even if gravity has to be modified, some form of dark matter will still be required." These quotes provide answers to the specified study questions based on the information in the paragraph.