In the vast universe, the rotation of galaxies continues to fascinate astronomers who seek to understand the mechanisms behind this fundamental movement. The orientation of galaxies, often perceived as random, actually reveals a more subtle organization. The alignment of galactic spins – the preferred direction in which galaxies rotate – has become a key area … Read more
In the vast field of cosmology, topological defects emerge as silent witnesses of the first fractions of seconds of the primordial universe. These unique structures, often stable, would have formed during cosmic phase transitions, crucial moments when the universe saw its fundamental symmetries break. These breaks left behind singular configurations of matter and energy, which, … Read more
The cosmic microwave background, often referred to as fossil radiation, is an extraordinary witness of the primordial universe. Originating from the time when the first atoms could form, this radiation reveals the state of the Universe approximately 380,000 years after the Big Bang. However, far from being perfectly uniform, it presents small temperature variations known … Read more
Since the end of the 1990s, contemporary astronomy has revealed an unsuspected facet of our cosmos: a mysterious force, dubbed dark energy, which represents about 70% of the total energy density of the Universe and is responsible for the acceleration of its expansion. This phenomenon is intimately linked to the cosmological constant, a notion introduced … Read more
The cosmological horizon problem embodies one of the major challenges in modern cosmology, questioning the very foundations of our understanding of the observable universe. This conundrum raises a fascinating question: how can extremely distant regions of the universe, seemingly without any causal contact, exhibit such surprising homogeneity, particularly seen in the cosmic microwave background radiation? … Read more
Baryonic acoustic oscillations (BAO) represent a fundamental phenomenon in cosmology, marking a crucial sequence in the history of the Universe. These primordial sound waves, which occurred in the hot plasma composed of baryons and photons, have left indelible traces visible in the large-scale structure of the Universe. By studying these oscillations, astrophysicists gain access to … Read more
Observations of the cosmos reveal mysteries that are intricately woven into the delicate fabric of the primordial universe. Among these invisible footprints, the Sachs-Wolfe effect holds a prominent place. It traces the memory of gravitational evolution through the anisotropies of the cosmic microwave background, this ancient breath imbuing every photon of the cosmic background radiation. … Read more
Black holes embody one of the deepest mysteries of the universe, revealing both the extreme power of gravity and the limits of current physics. These celestial objects, formed from the collapse of massive stars, concentrate an incredible mass into an infinitely small space. As a result, they become natural laboratories where quantum gravity and quantum … Read more
The matter-antimatter asymmetry in the Universe remains a fascinating enigma in cosmology and fundamental physics. While the Standard Model predicts a symmetric creation of matter and antimatter during the Big Bang, our observations show a striking predominance of matter in the current Universe. This imbalance raises profound questions about the nature of physical laws, the … Read more
In the rapidly expanding field of high-energy physics, supersymmetry stands out as a revolutionary approach aimed at surpassing the limits of the standard model. This theory proposes that every fundamental particle, whether a fermion or a boson, has a supersymmetric partner whose spin differs by half a unit. Moreover, recent advancements in the detection of … Read more