The presence of liquid water in the outer solar system generates considerable scientific interest, particularly due to its potential link to life beyond Earth. While most visible liquid water is confined to our planet, recent discoveries suggest that this vital element also exists in other forms, primarily as ice, on several moons and distant celestial … Read more
IN BRIEF Cosmic rays: high-energy subatomic particles coming from space. Messengers of violent events in the universe. Composed mainly of protons and atomic nuclei. Create large showers of secondary particles upon their manifestation. Constantly bombard the Earth and impact our atmosphere. Represent one of the greatest dangers for astronauts in space exploration. Play a crucial … Read more
IN SHORT Variable stars: celestial bodies that show variations in brightness. Two main types: Cepheids and RR Lyrae stars. Periodic volume variations affecting brightness and spectrum. Essential for estimating astronomical distances. Constantly increasing cataloging, with a variety of characteristics. Used to determine stellar dynamics. Long-period variable stars: red supergiants with marked brightness variations. Interest in … Read more
IN BRIEF Primordial nucleosynthesis: the initial formation of elements after the Big Bang. Origin of matter: explained by the Big Bang model. Carbon chemistry: the foundation of life on Earth with sugar, proteins, lipids. First molecule: the helium hydride ion (HeH+) could be the very first formed element. Complexification of atoms: evolution of hydrogen atoms … Read more
IN BRIEF Relativistic jets: ejections of matter at speeds close to that of light. Source: originating from accretion disks around black holes. Observation: monitoring a black hole for 15 years by an international team of astronomers. Power: the most powerful phenomena observed in astrophysics. Structure: jets maintain a narrow structure over vast distances. Rotation: the … Read more
IN SHORT Quantum Gravity: Unification of quantum mechanics and general relativity. Loop Quantum Gravity: Model based on the canonical quantization of relativity. String Theory: Automatically integrates quantum gravity. Theoretical Challenges: Ongoing research to integrate quantum field theories and general relativity. Fluctuations of spacetime: Fundamental concepts in quantum gravity. Spin Foam Models: Innovative approaches to quantum … Read more
IN BRIEF State of matter: Plasma, the fourth state after solid, liquid, and gaseous. Composition: Composed of electrons, ions, and neutral gases. Examples: Present in the sun and other stellar environments. Measurements: Conducted by space probes to study the dynamics of plasmas. Applications: Research in astrophysics and high-temperature plasma physics. Interactions: Influenced by external forces … Read more
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