IN BRIEF Composition: Superfluid of neutrons, fluid of electrons, and superconducting protons. Density: Mass equivalent to 1.4 times that of the Sun, compressed into a sphere about 20 km in diameter. Rotation: Extremely fast rotations, periods generally varying around 30 milliseconds. Stellar remnant: Remains of a massive star that has exploded in a supernova. Gravitational … Read more
IN SHORT Gamma bursts: among the most powerful explosions in the universe. Result from the collapse of massive stars into black holes. Produce jets of radiation with high energy. Violent events: kilonovas and hypernovas. Recent observations thanks to the James Webb telescope. Contribute to the understanding of cosmic formation. Potential danger to Earth, despite the … 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 Microwave Background (CMB): fossil radiation of the universe Fluctuations: temperature differences, indicating anisotropies Blue regions: cooler, indicating areas of low energy Red regions: warmer, signaling areas of high energy Inflation: early period of the universe explaining certain fluctuations Measurements by satellites WMAP and Planck CMB reveals characteristic B modes Temperature dipole: origin … Read more
IN BRIEF Satellite Planck launched in 2009 by the European Space Agency. Objective: to map the anisotropies of the cosmic radiation. Discovery of a supercluster of galaxies through its imprint on the cosmic background radiation. Analysis of the cosmic microwave background, light emitted 380,000 years after the Big Bang. Onboard instruments: Low Frequency Instrument (LFI) … Read more
IN BRIEF Expansion of the Universe: phenomenon of galaxies moving away from each other. Observation by Edwin Hubble in 1929 on distance and redshift. Dynamic spaces: influence of gravity on space-time. Speed of expansion and its impact on cosmology. Origin of the Universe: about 13.8 billion years ago. Big Bang Theory and its implications for … Read more
IN BRIEF Solar Wind: flow of particles ejected from the Sun. Origin: comes from the solar corona. Plasma: fills the heliosphere up to 100 astronomical units. Solar Storms: caused by clusters of sunspots. Earth’s Magnetic Field: protects Earth from ionized particles. Auroras: result from the interaction between solar wind and Earth’s atmosphere. Nuclear Reactions: source … Read more
IN BRIEF Thermodynamics: Study of physical properties as a function of temperature. Thermal equilibrium: State where temperature reaches a stable value. Astrophysics: Application of thermodynamic principles to astronomical phenomena. Wien’s Law: Principles used to analyze radiation in the universe. Mass-luminosity relation: Correlations between mass and light emission from stars. Understanding accretion disks and other astrophysical … Read more
IN BRIEF Neutrinos are nearly massless subatomic particles. They have no electric charge, making their identification complex. They act as messengers of cosmic phenomena. Neutrinos come from energetic events such as supernovae. They allow for a better understanding of astrophysical phenomena. These particles are more abundant than dark matter. Neutrino astronomy offers a complementary perspective … Read more
IN BRIEF Black hole: a region of space with an intense gravitational field. Accretion disk: matter in orbit around a celestial body, often composed of gas and dust. Accretion disks around supermassive black holes: key to observing the accretion of matter. Inclination of the accretion disk and angle of observation influence the detected brightness. Emission … Read more