Last update: February 23, 2026

The Universe: Matter... or Information?

Information as the fundamental building block of the universe, blending bits and cosmic structures

From Matter to Information: A Paradigm Shift

For centuries, physics has sought to reduce the complexity of the Universe to its most elementary components. We have identified matter, energy, space, and time as the pillars of our reality. But a question arises from the most recent theories: What if a piece of the puzzle is missing? What if, behind the dance of particles and the curvature of spacetime, there lies an even more fundamental entity: information?

The idea may seem abstract, even philosophical. Yet, it is at the heart of some of the deepest advances in theoretical physics, linking the thermodynamics of black holes to quantum mechanics. Information is no longer just a mathematical concept or a measure of our ignorance; it may be a physical quantity, with its own reality, on par with mass or energy.

The Landauer Principle: When Information Meets Physics

A Revolutionary Idea

The first solid bridge between information and physics was built by Rolf Landauer (1927-1999), a German physicist working at IBM. In 1961, in an article titled "Irreversibility and Heat Generation in the Computing Process," he formulated a principle that became fundamental: information has a physical reality. His famous principle, the Landauer Principle, states that in any computing system, the irreversible erasure of a bit of information must necessarily be accompanied by the dissipation of energy in the form of heat.

The Formula Linking Information and Thermodynamics

Mathematically, this is expressed by the equation: \( E = k_B T \ln 2 \) where \(E\) is the minimum energy dissipated, \(k_B\) is the Boltzmann constant, and \(T\) is the temperature of the system. This is a fundamental law of nature. Information is intangible, but its manipulation and erasure have physical consequences, measurable in the material world. This was the first clear demonstration that information is a physical quantity subject to thermodynamics. The Landauer Principle was experimentally verified in 2012 by researchers at CEA-Saclay, who trapped a microscopic particle with a laser to simulate a "bit" and measured the heating produced during its erasure.

The Information Paradox

The role of information became unavoidable with the study of black holes. In the 1970s, Jacob Bekenstein (1947-2015) and Stephen Hawking (1942-2018) revolutionized our understanding of these objects. Hawking demonstrated that a black hole is not completely black: it emits radiation (the Hawking radiation) and eventually evaporates.

What Happens to the Lost Information?

This created a major problem: the information paradox. If a black hole evaporates, what happens to the information about the objects that fell into it? Is it destroyed? In quantum physics, nothing is truly erased in an isolated system. Information can hide or disperse, but it is never lost. The potential solution to this paradox emerged from another discovery by Bekenstein: the entropy of a black hole is proportional to the surface area of its event horizon, not its volume.

The Holographic Principle

The maximum amount of information that can be contained in a region is proportional to the surface area of its boundary. From this idea emerged the holographic principle, developed by Gerard 't Hooft (1946-) and Leonard Susskind (1940-). According to this bold theory, our perception of a three-dimensional cosmos (height, width, depth) might just be a projection, like a giant hologram. All the information describing our reality would actually be encoded on a two-dimensional surface, located at the edge of the Universe. What appears to us as volume would only be a "three-dimensional image" projected from this surface.

Information as a Fundamental Constituent: The Digital Turn

If information is so closely linked to entropy, energy, and the geometry of spacetime, could it not be more fundamental than matter itself? This is the hypothesis of physicists like John Archibald Wheeler (1911-2008), who popularized the maxim "It from bit". Every element of physical reality (It) emerges from a fundamental base of information (Bit). The Universe would be a giant quantum system, computing its own reality from which spacetime and matter-energy emerge.

Information in Major Physical Theories

Summary of Concepts Linking Information to Fundamental Physics
Concept / Principle	Proposed by	Key Idea
Landauer Principle (1961)	Rolf Landauer (1927-1999)	The erasure of a bit of information dissipates energy, experimentally verified (2012). Information has a thermodynamic reality.
Black Hole Entropy (1972)	Jacob Bekenstein (1947-2015)	The entropy of a black hole is proportional to the surface area of its horizon. Links information to geometry.
Hawking Radiation (1974)	Stephen Hawking (1942-2018)	Black holes emit radiation and evaporate, raising the paradox of information conservation.
"It from bit" (1989)	John Archibald Wheeler (1911-2008)	Physical objects (it) derive their existence from information (bit). Information is primordial.
Holographic Principle (1993)	Gerard 't Hooft (1946-), Leonard Susskind (1940-)	All information contained in a volume can be encoded on its boundary surface. The Universe could be a hologram. Strongly supported hypothesis, not proven.
Quantum Information Mechanics	David Deutsch (born 1953)	Physical reality is a process of quantum information processing. Qubit as the fundamental building block of reality. Active research program in quantum computing.

N.B.: While these concepts are firmly rooted in theoretical physics, they are not yet consensus. The status of information as a fundamental component, on par with spacetime, remains a working hypothesis at the intersection of quantum physics, cosmology, and the philosophy of science.

Towards a Physics of Information

So far, we have seen the Universe as a stage where physical phenomena unfold, and ourselves as mere spectators. Information may not be a "thing" we can touch, but it could well be the secret ingredient that structures reality. A fascinating idea that invites us to rethink our place in the cosmos!