Alain Picard Herbig-Haro objects reveal the spectacular dynamics of the early moments of stellar life, where stellar jets from young stars pierce through the surrounding gas and dust with astonishing violence. These phenomena, observable as luminous emission nebulae, mark shock zones where expelled materials encounter the interstellar medium. Recent imaging, particularly through the James Webb Space Telescope, … Read more
At the heart of cosmic mysteries, cataclysmic variables reveal themselves as fascinating stellar systems, where the astral struggle between two stars creates spectacles as spectacular as they are unpredictable. Like volcanic eruptions on Earth, these binary stars trigger phenomena of phenomenal intensity, recalling by analogy the volcanic detonations, pyroclastic flows, and ash clouds observed in … Read more
Blue hypergiants represent the apex of mass and brightness in the stellar hierarchy. These rare and impressive objects dominate their galactic environment with exceptional energy and power. They are the stage for extreme phenomena related to nuclear fusion and represent a crucial step in understanding cosmic dynamics as well as the formation of stars in … Read more
Brown dwarfs intrigue and captivate contemporary astronomers, gradually redirecting our gaze towards these singular celestial bodies whose nature still eludes a rigid classification. These substellar objects intercalate between the gigantic gas giants like Jupiter and the cold stars of low mass, proving to be both luminous and tenuous, massive yet incapable of sustaining classical nuclear … Read more
In the vast universe, measuring astronomical distances has been a major challenge since the beginnings of astrophysics. The variable stars known as cepheids have become fundamental keys for this task, acting as standard candles that allow us to estimate cosmic distances with precision. Their discovery and understanding have revolutionized our ability to map the universe, … Read more
Magnetars represent one of the most fascinating and extreme manifestations of stellar physics. These neutron stars, compact remnants of massive stars that exploded in supernovae, are distinguished by the colossal power of their magnetic field, reaching up to 1015 gauss, which is a trillion times that of Earth. This phenomenal intensity generates unique astrophysical phenomena, … Read more
IN BRIEF Spatial curvature of the universe: types and implications. Hypotheses about the shape of the universe: closed, open, or flat. Relationship between curvature and the temporal evolution of the universe. Impact of the Big Bang on the conception of time and space. Possibility of a crumpled universe or a TORUS-Universe. Discovery of a tiny … Read more
IN BRIEF Light spectra: Analysis of the light emitted by stars. Decomposition of white light via a prism or a grating. Absorption spectrum: Presence of dark lines, indicating chemical elements. Hydrogen: Identification by its specific emission lines. Visible colors: Observations ranging from violet to red. Emission lines: Allow identification of elements present in stars. Importance … Read more
IN BRIEF Giant gas planets: Jupiter and Saturn, formed nearly 5 billion years ago. Recent discovery of wandering double giant planets in the Orion nebula. Observation of planetary birth through gravitational collapse. Mysteries surrounding the formation and atmospheres of gas giants. Effects of atmospheric phenomena on Jupiter, including hurricanes and clouds. New theoretical models proposed … Read more
The evolution of planetary habitability represents a fundamental scientific quest, intertwining astronomy, geology, climatology, and biology. Since the discovery of the first exoplanets, researchers have been trying to understand how certain planets can support life, relying on Earth as the main model. The exploration of planetary systems, habitable zones around stars, and the study of … Read more