Since Antiquity, philosophers and scientists have questioned the nature of nothingness and vacuum (Parmenides, Democritus, Pascal, Kant, Heidegger...). These metaphysical notions, though widely explored, remain enigmatic.
Nothingness, defined as total absence (of matter, energy, information, spacetime), cannot be conceived without attributing some form of existence to it. As soon as we imagine it, it becomes something - hence the paradox. If nothingness cannot create or be thought of, let us turn to the vacuum, distinct from nothingness.
Unlike nothingness, vacuum is the absence of matter in a volume of space. But does it truly exist?
"Just as the speed of light is unsurpassable, absolute zero is unattainable. Radiation completely fills the 'vacuum', making it dynamic."
Gottfried Wilhelm Leibniz (1646-1716) formulated this paradox: "Why is there something rather than nothing?" "Nothing" seems simpler, yet our Universe is very real.
The expanding Universe is gradually cooling. Its residual energy tends towards an absolute minimum, corresponding to the ground state of the quantum vacuum.
"This indestructible energy background, in perpetual renewal, could be the key to a cyclic cosmology, where each Universe is but an ephemeral fluctuation of an eternal vacuum."
The first second of our history 
Time Dilation: Relativistic Mirage or Reality?
Space Through Time: A Constantly Evolving Concept
The Expanding Universe: What Does "Creating Space" Really Mean? 
From Nothingness to the Cosmos: Why Is There Something Rather Than Nothing? 
Glossary of Astronomy and Astrophysics: Key Definitions and Fundamental Concepts 
How can the Universe measure 93 billion light-years? 
How can we say that the Universe has an age? 
First Proof of the Expansion of the Universe 
Space-time slices of the observable Universe 
Dark Ages of the Universe 
Alternative theories to the accelerated expansion of the universe 
The primitive atom of Abbot Georges Lemaître 
Great walls and filaments: the great structures of the Universe 
The Origins of the Universe: A History of Cosmic Representations 
Lyman-alpha Blobs: Gaseous Traces of the First Galaxies 
Gamma-Ray Bursts: The Ultimate Breath of Giant Stars 
Perspective on the Inflation of the Universe 
The Planck Universe: the Image of the Universe Becomes Clearer
The sky is immense with Laniakea 
Abundance of chemical elements in the Universe 
The Symmetries of the Universe: A Journey Between Mathematics and Physical Reality 
The Geometry of Time: Exploring the Fourth Dimension of the Universe 
How to measure distances in the Universe? 
Why ‘nothing’ is impossible: Do nothingness and emptiness exist? 
The Horizon Problem: Understanding the Uniformity of the Cosmos 
What is Dark Matter? The Invisible Force Shaping the Universe 
Metaverse, the next stage of evolution 
Multiverse: An Ocean of Expanding Space-Time Bubbles 
Cosmological Recombination: When the Universe Became Transparent 
The cosmological and physical constants of our Universe 
The Thermodynamics of the Sandpile and the Avalanche Effect 
The engine of the accelerated expansion of the Universe 
The X-Ray Universe: When Space Becomes Transparent 
The oldest galaxies in the universe 
Hubble constant and expansion of the Universe 
Dark Energy: When the Universe Defies Its Own Gravity 
What is the Size of the Universe? Between Cosmological Horizon and Infinity 
Quantum Vacuum and Virtual Particles: The Physical Reality of Nothingness 
Paradox of the dark night 
Journey into the Heart of Paradoxes: The Enigmas That Revolutionized Science 
Cosmic Microwave Background: The Thermal Echo of the Big Bang