The fluctuations of the cosmic microwave background

Les fluctuations du fond diffus cosmologique

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

The large ground-based telescopes for cosmology

Les grands télescopes terrestres pour la cosmologie

IN SHORT Gran Telescopio de Canarias: Primary mirror with a diameter of 10.4 meters. European Extremely Large Telescope (ELT): Expected to open in 2027 with a mirror of 39 meters. Very Large Telescope (VLT): Flagship equipment of European astronomy. Southern African Large Telescope (SALT): Mirror of 11.1 meters. Schmidt Telescopes: Used for photographic astrometry. Large … Read more

Luminous fossils: the light of the beginnings of the universe

Les fossiles lumineux : la lumière des débuts de l'univers

IN BRIEF Cosmic background radiation: first light emitted, 380,000 years after the Big Bang. 3D representation of the universe’s original glow. Detection of the cosmic microwave background through advanced observations. Discovery of cosmic structures like bubbles a billion light-years wide. Formation of the first atoms and transition from an opaque state to a transparent state. … Read more

The models of the end of the universe: Big Freeze, Big Rip, Big Crunch

Les modèles de fin de l'univers : Big Freeze, Big Rip, Big Crunch

IN BRIEF Big Freeze: hypothesis that the Universe will continue to expand, leading to a heat death. Big Crunch: scenario of a terminal collapse of the Universe, where everything converges into a singularity. Big Rip: theory that the expansion of the Universe would accelerate to the point of tearing apart all matter. These models explore … Read more

The formation of the first atoms after the Big Bang

La formation des premiers atomes après le Big Bang

IN BRIEF Primordial nucleosynthesis: Formation of the first atoms after the Big Bang. Timing: Approximately 380,000 years after the Big Bang. Elements formed: Mainly hydrogen and helium. First molecule: The ion HeH+, possibly the first molecule. Conditions: Initial temperatures around 10^9 K. Electrons and atoms: Electrons combine with nuclei to form atoms. In the vastness … Read more

The multiverse: science or fiction

Les multivers : science ou fiction

IN BRIEF Multiverse: scientific concept regarding the existence of multiple universes. Parallel dimensions: possibility of variations within the same universes. Cosmological theories: scientific foundations of the multiverse idea. Fiction: widely explored in literature, cinema, and television. Metaverse: distinction between created virtual universes and natural universes. Science and fiction: ongoing debate about the reality of the … Read more

The great discoveries of the Planck satellite

Les grandes découvertes du satellite Planck

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

The concept of time in cosmology

Le concept de temps en cosmologie

IN BRIEF Cosmic time: central concept in cosmology to model the universe. History of objects: each element of the universe has its own temporal journey. Cosmological models: assume uniformity and isotropy of the universe. Coordination of events: necessary interaction between time and space to structure the universe. General relativity: revolutionized the perception of time in … Read more

Dark energy and its role in the universe

L'énergie sombre et son rôle dans l'univers

IN BRIEF Dark energy: makes up about 68% of the Universe. Accelerates the expansion of the Universe due to its repulsive nature. Dark matter and dark energy: two great mysteries of astrophysics. Recent progress shows that the expansion of the Universe is faster than expected. Use of telescopes like Hubble and Euclid to study these … Read more

Dark matter: the great cosmological mystery

La matière noire : la grande énigme cosmologique

IN BRIEF Dark matter makes up about 85% of the mass of the Universe. It is invisible and undetectable, making its study complex. Represents one of the biggest mysteries of modern cosmology. Its existence is necessary to explain the movement of galaxies. Theories like modified gravity attempt to unravel this mystery. Less than 5% of … Read more