Cosmic inflation unveils a fascinating chapter in the history of the primitive universe, marking a period of frenzied expansion that precedes the formation of cosmic structures such as galaxies and star clusters. This theory, initially formulated in 1980 by physicist Alan Guth, offers a compelling explanation for several enigmas of the standard cosmological model, including … Read more
In brief: Between diffuse matter and stellar explosions, interstellar bubbles trace the dynamics of a cosmos in perpetual change. These hollow nebulae, sometimes visible in X-rays or in the radio domain, emerge as witnesses of the winds projected by massive stars or debris from ancient supernovae. The complex interaction between these stellar winds and the … Read more
At the heart of the first minutes of the Universe, a decisive phenomenon took place, marking the origin of matter as we know it today: primordial nucleosynthesis. This brief but intense period allowed the initial formation of light atomic nuclei, notably hydrogen, helium, and lithium. The story of this cosmic alchemy dives into an expanding … Read more
The cosmic microwave background (CMB) presents itself as an almost perfect and captivating imprint of what the Universe was like in its early moments, a true echo of the Big Bang enveloping the cosmos. This incessant radiation, invisible to the naked eye, has traversed nearly 14 billion years of expansion to provide us with crucial … Read more
The enigma of {{strong|dark energy}} has fascinated astrophysicists for several decades. First observed with the discovery of a {{strong|cosmic acceleration}} in the expansion of {{strong|the universe}} at the end of the 20th century, this mysterious force challenges the classical knowledge of modern {{strong|cosmology}}. Constituting about 70% of the total content of the universe, as revealed … Read more
Since the dawn of modern cosmology, dark matter has intrigued researchers with its fundamental role in the structuring of the universe while remaining practically elusive. This mysterious substance, which accounts for about 85% of the total mass of the invisible universe, profoundly influences the movement of galaxies and the evolution of large cosmic structures. Yet, … Read more
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 vastness of the universe, beyond the twinkling of galaxies, lie enormous regions practically devoid of visible matter, the cosmic voids. These areas, true depressions in the large-scale structure of the cosmos, offer a striking contrast to the dense filaments and galactic clusters that compose the cosmic web. Their characteristics, formation, and role in … 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
Primordial nucleosynthesis, a fundamental phenomenon marking the chemical genesis of the universe, unfolded during the very first minutes following the Big Bang. It was during this intense phase that the first light atomic nuclei appeared, giving birth to elements that will constitute the fundamental building blocks of cosmic matter. This crucial step conditioned the cosmic … Read more