Image description: At room temperature, the wavelength of particles is extremely small (~2x10−11 m). As temperature decreases, particle speed decreases, frequency decreases, and wavelength increases until it forms a giant wave. Just as the speed of light is insurmountable, absolute zero is unattainable by matter.
Since antiquity to the present day, many thinkers have been interested in "nothingness" and "vacuum" (Parmenides, Euripides, Leucippus, Democritus, Plato, Aristotle, Saint Augustine, Pascal, Leibniz, Kant, Heidegger, Bergson, etc.). Countless texts have been written on this subject, but these metaphysical concepts remain mysterious and open to questioning.
- Leonardo da Vinci (1452-1519): "Nothingness has no center, and its limits are nothingness."
- Blaise Pascal (1623-1662): "For after all, what is a man in nature? A nothing with regard to the infinite, a whole with regard to nothingness, a middle between nothing and everything,"
- Arthur Schopenhauer (1788-1860): "Nothingness after death? Is it not the state we were accustomed to before life?"
- Victor Hugo (1802-1885): "Nihilism has no substance. Nothingness does not exist and zero does not exist. Everything is something. Nothing is nothing."
- Friedrich Wilhelm Nietzsche (1844-1900): "I think, therefore it is."
- André Malraux (1901-1976): "The greatest mystery is not that we are thrown at random on earth. It is that in this prison, we draw from ourselves images powerful enough to deny our nothingness."
Can Nothingness Exist?
Nothingness being the absence of "everything," we can only think of nothingness by attributing some form of existence to it. Indeed, if in our mind something that represents nothingness appears, then it is a paradox because nothingness is neither matter, nor energy, nor information, nor space-time, nor something, nor even nothing.
If nothingness could not create anything and cannot be conceived, then let’s consider the vacuum which is not nothingness.
The "absolute vacuum" is the absence of matter in a certain volume of space.
Can the Vacuum Exist?
Classical physics tells us that matter and energy are the same thing (E=mc2).
In 1900, Max Planck (1858-1947) discovered that radiation is pure energy (e=hν). However, we do not know of any place where there is neither matter nor energy.
Quantum physics tells us that particles always possess a non-zero amount of momentum (nothing is static in the Universe). Any matter with momentum has a temperature above absolute zero (0 Kelvin). Any matter with a temperature emits radiation, thus energy. However, absolute zero is a theoretical temperature unattainable by matter due to its intrinsic quantum properties.
Every system has energy, even when it is very close to absolute zero. Its minimum energy corresponds to the energy of its ground state, and the kinetic energy of its ground state cannot decrease.
Just as the speed of light is unsurpassable, absolute zero is unattainable. Thus, radiation emitted by matter propagates throughout the Universe and fills the "vacuum." It is said that the vacuum is stirred by virtual particles, from which observable matter may arise in the light of an excitation.
In summary, the vacuum always has a minimum energy, and this minimum energy will be necessary for the existence of all matter (E=mc2).
Image description: The first light of the observable universe as seen by the Planck mission (March 2013). This embryonic universe already has an incredible amount of detail. The tiny temperature irregularities we see are scars left by the quantum vacuum on the surface of spacetime. Each small pixel will evolve into clusters of galaxies (at this moment, the Milky Way is just a quantum fluctuation of the vacuum). Credit: ESA and Planck collaboration.
Gottfried Wilhelm Leibniz (1646-1716) in "Principles of Nature and Grace" poses this question, "Why is there something rather than nothing?" Indeed, "nothing" is much simpler than the existence of something, but our Universe is indeed here!!!
The question then is: where did it emerge from?
This simple question brings back the concepts of nothingness and vacuum to our minds.
The Big Bang theory tells us that about 13.8 billion years ago, in a fraction of a second, the universe was born. This seems true because we detect everywhere, in all directions of the cosmos, the "cosmic microwave background" from the earliest moments.
Does this mean that our observable Universe had a beginning?
No, within the framework of quantum field theory, our Universe would have emerged from the pre-existing quantum vacuum.
Currently, we observe that our Universe occupies an expanding and cooling space. Its temperature, although very low (2.7 K), is above absolute zero. This low temperature allows us to see the first light of our universe (Planck mission shown).
However, this temperature continues to radiate its surroundings while cooling further, so we cannot say that there is nothing beyond the observable Universe.
This small energy will fade until it reaches a minimal energy. The Universe will then have returned to its initial state, that is, the ground state of the vacuum or otherwise, the default state of what we consider as nothingness.
When the matter, space, and time of our Universe have disappeared, the energy, still present, will be conserved in the quantum vacuum teeming with fluctuations (in an atom, there are more quantum fluctuations than stars in the universe).
This minimal energy, below which it is impossible to go, preexists and cannot be created ex nihilo.
Then, another fluctuation of the quantum vacuum might give rise to another universe and start a new story quite different where matter, energy, space, and time are once again united.
This background energy, which is preserved indefinitely, periodically renews a different story.
All metaphysical concepts (nothingness, vacuum, nothing, non-being, Planck era, etc.) can be unified in the energy of the vacuum agitated by virtual particles appearing and disappearing incessantly. The vacuum is the origin of everything, and what we consider as nothingness could be the link between us and the infinite.
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 
Always closer to the Big Bang 
Lyman-alpha
bubbles 
The mystery of gamma bursts 
Perspective on the Inflation of the Universe 
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 
How to measure distances in the Universe? 
Do nothingness and emptiness exist? 
Mystery of the Big Bang, the problem of the horizon 
The first second of our history 
Does dark matter exist? 
Metaverse, the next stage of evolution 
The multiverse long before the Big Bang 
What is recombination in cosmology? 
The cosmological and physical constants of our Universe 
Thermodynamics of the sand pile 
What does the equation E=mc2 really mean? 
The engine of the accelerated expansion of the Universe 
The
Universe of X-rays 
The oldest galaxies in the universe 
Hubble constant and expansion of the Universe 
Dark energy
is needed 
Gravitational waves 
How
big is the universe? 
The vacuum has considerable energy 
Paradox of the dark night 
Paradoxes in physics