IN BRIEF Origin of galaxies: results from small fluctuations in density in the primitive universe. Formation: process by merging dwarf galaxies and gravitational collapse. Types of galaxies: include spiral galaxies, with a disk of gas, dust, and stars. Evolution: linked to each galaxy’s ability to create stars. Environment: evolution depends on local physical and chemical … Read more
IN BRIEF Critical density : key value characterizing the energy of the Universe. Relationship between the density of the Universe and its curvature. Impact of a density lower than critical density: eternal expansion. Consequences of a density higher : possibility of a Big Crunch. Standard cosmological model based on general relativity. Measurement of critical density: … Read more
IN BRIEF Cosmic filaments: thread-like structures made up of galaxies and galaxy clusters. Comprise the cosmic web, a complex network of empty spaces surrounded by walls of matter. Filaments can extend for hundreds of millions of light-years. First observed, they reveal the largest cosmic structures in rotation. Organize the matter of the Universe on a … Read more
IN SHORT The interaction between galaxies results from the gravitational field of other galaxies. Galactic collisions generate instabilities promoting the formation of spiral arms. Following a merger, stars ignite, and supermassive black holes activate. These events cause superwinds and cosmic chaos, but not total disaster. Many galaxies have already experienced interactions in their history. The … Read more
IN BRIEF Earth observation satellites: tools for geophysical and geographical data. Remote sensing: modern technique for monitoring the planet. TILBA® laser communication: receiving data at very high speeds. Instantaneous observation: covering large areas in seconds. Varied missions: from crop inventory to volcanic studies. Geostationary orbits: constant monitoring of the same region. Multiple applications: navigation, communications, … Read more
IN SHORT Stellar nucleosynthesis: A set of nuclear reactions occurring inside stars. Creation of chemical elements: Massive stars generate heavy elements through nuclear reactions. Star formation: They form from clouds of gas rich in hydrogen and helium. Primordial nucleosynthesis: Formation of light elements during the origin of the Universe. Types of nucleosynthesis: Includes stellar, primordial, … Read more
IN BRIEF Supernova: massive explosion of a star in the universe. It is the largest explosion observable in space. Results in ejections of matter and shock waves at impressive speed. Significant impact on the enrichment of the interstellar medium in heavy elements. Increases the flow of cosmic rays in the galaxy. Studies related to cosmic … Read more
IN BRIEF Numerical simulations to study the Universe. Used by physicists to simulate the inflation of the Universe. Objective: to create a model of the entire observable Universe. Analysis of stars, galaxies, black holes, etc. Essential tool for understanding cosmological processes. Simulations aiding in retracing the history of the Universe. Illustration of the ongoing expansion … Read more
IN BRIEF Four fundamental forces: gravitation, electromagnetism, strong nuclear force, and weak nuclear force Gravity: governs weight and the trajectories of celestial bodies Electromagnetic force: regulates interactions between charged particles Strong nuclear force: holds protons and neutrons together in the atomic nucleus Weak nuclear force: responsible for nuclear transformations Standard model: theorizes the fundamental interactions … Read more
IN BRIEF Quasars: Immense black holes at the heart of galaxies. Energy emission: They produce significant amounts of energy by devouring matter. Cosmic evolution: Help in understanding the evolution of the Universe. Interaction with galaxies: Influence the formation and evolution of galaxies. Quasar winds: Produce jets of radiation altering the galactic environment. Energy role: Among … Read more