le 27 septembre 2024, 10h45 à 12h45, Natalie Webb, salle Jules Verne, OMP, site Belin Resumé: Thanks to large surveys such as Gaia, the Sloan Digital Sky Survey (SDSS), GALEX, 2MASS, NVSS, FIRST, XMM-Newton and Chandra, we have catalogued many different stars and galaxies. We have also found some very exotic objects, especially when we observe […]
le 20 septembre 2024, 10h45 à 12h45, Katia Ferrière, salle Jules Verne, OMP, site Belin Resumé: I will take you on a cosmic journey from the Earth to the far reaches of the observable Universe. We will first spend some time in the solar system, where I will show how the radius of the Earth and […]
le 13 septembre 2024, 10h45 à 12h45, Luigi Tibaldo, salle 225-226, IRAP, site Roche Resumé: Cosmic rays are energetic particles first observed around the Earth with energies ranging from MeV to above 10^20 eV and with approximately isotropic arrival directions. A most remarkable change of the cosmic-ray spectrum occurs around 10^15 eV. Below this energy, the […]
le 6 septembre 2024, 10h45 à 12h45, Arturo Lopez, salle Jules Verne, OMP, site Belin Resumé: The phase of a wave can only be defined unambiguously for complex waves. This strange quantity appears at the core of all physics: from the quantification of atomic levels or of the electric charge to the source of the electromagnetic […]
le 27 octobre 2023, 10h45 à 12h45, Victor Réville, salle Jules Verne, OMP, site Belin Resumé: Magnetic reconnection is a fundamental process in astrophysics. It allows converting magnetic into thermal and kinetic energy in astrophysical plasmas. In the solar atmosphere, it has been associated with solar storms, flares, and the release of energetic particles and […]
le 15 décembre 2023, 10h45 à 12h45, Fernando Cruz, salle Jules Verne, OMP, site Belin Resumé: Accretion is among the most important physical processes during the formation of stars. Eruptive young stars are young stellar objects (YSOs) that experience sudden and dramatic accretion outbursts, where the mass accretion rate can increase by up to 5 […]
le 8 décembre 2023, 10h45 à 12h45, Pierre Marchand, salle Jules Verne, OMP, site Belin Resumé: Magnetic fields play a major role during the formation of stars. From the interstellar medium where they act on the formation on pre-stellar cores, to protoplanetary disks in which they regulate angular momentum and create outflows, an accurate description […]
le 1 décembre 2023, 10h45 à 12h45, Guillaume Loizelet, salle Jules Verne, OMP, site Belin Resumé: In this session, I will review the results obtained by historians of astronomy over the last fifty years, which have led to a complete rethinking of the idea of a scientific revolution developed in the mid-twentieth century.I will first […]
le 24 novembre 2023, 10h45 à 12h45, Guillaume Loizelet, salle Jules Verne, OMP, site Belin Resumé: Using the available databases, it was possible for ancient « astronomers » to propose models to account for observable celestial movements. The climax of these attempts is undoubtedly the great mathematical synthesis (known as the Almagest) written in Greek by the […]