Information Density as a Source of Gravity

Quick Answer

Gravity may not be a fundamental force at all. A growing body of theoretical work suggests gravity could emerge from differences in information density and entropy, with mass influencing spacetime only because it carries information content. In this view, gravitational attraction is thermodynamic, arising from the universe's tendency to maximize disorder. If true, objects with identical mass but different internal entropy might generate measurably different gravitational forces, offering a testable prediction that could revolutionize physics.

Why This Matters

Understanding whether gravity is fundamental or emergent goes beyond academic curiosity. This question directly impacts our pursuit of a unified theory of physics, our understanding of dark matter and dark energy, and potentially opens pathways to technologies we cannot yet imagine. The information-gravity connection also links cutting-edge quantum information science to cosmology, suggesting that the computational content of reality shapes the structure of spacetime itself.

Key Takeaways

Black hole thermodynamics revealed deep links between gravity, entropy, and information in the 1970s when Bekenstein and Hawking showed black holes have entropy proportional to their horizon area
Ted Jacobson derived Einstein's field equations from thermodynamic assumptions in 1995, treating gravity as an "equation of state" rather than a fundamental law
Erik Verlinde's 2011 entropic gravity model describes gravity as an entropic force arising from changes in information associated with matter's position
Quantum entanglement may be the fabric of spacetime, with gravity emerging from how entanglement is distributed across space
Information itself carries mass according to Landauer's principle, with one bit at room temperature having an equivalent mass of approximately 3.19 × 10⁻³⁸ kg
Testable predictions exist: ordered vs. disordered systems of identical mass might produce measurably different gravitational effects

The Basics

From Black Holes to Information Physics

The connection between gravity and information emerged from black hole physics. In the 1970s, Jacob Bekenstein discovered that black holes have entropy proportional to their event horizon area, not their volume. Stephen Hawking then showed that black holes emit thermal radiation, behaving like hot bodies with a temperature inversely proportional to their mass. These discoveries revealed that gravity and thermodynamics are deeply intertwined.

The implications were profound: if black holes carry enormous entropy and information, spacetime itself must have informational properties. This wasn't merely a curiosity. Black hole entropy scales with area rather than volume, suggesting that all the information about what falls into a black hole is somehow encoded on its two-dimensional surface. This observation evolved into the holographic principle, which posits that information in any volume of space can be fully described by data on its boundary.

Jacobson's Thermodynamic Spacetime

In a landmark 1995 paper, physicist Ted Jacobson turned these insights on their head. Rather than starting with Einstein's equations and deriving thermodynamic properties, he assumed a relationship between entropy and horizon area and worked backward. The result was stunning: he re-derived Einstein's field equations of general relativity purely from thermodynamic principles.

In Jacobson's approach, the geometry of spacetime emerges as an "equation of state" from underlying thermodynamic principles, much like how the ideal gas law relates pressure, volume, and temperature. Gravity is not fundamental in this picture but rather a macroscopic phenomenon arising from microscopic degrees of freedom, similar to how temperature is not fundamental but emerges from the collective motion of particles.

Verlinde's Entropic Gravity

Building on Jacobson's work, Erik Verlinde in 2011 proposed an explicit model of entropic gravity. In Verlinde's picture, when matter moves, the information (degrees of freedom) on enveloping "holographic screens" changes, and this leads to an entropic force that we interpret as gravity. Essentially, gravity results from the universe's tendency to increase entropy: things fall together because there is a gain in entropy when they do.

This is analogous to how diffusion or pressure result from entropy gradients. As one science writer put it, "gravity results from the same random jiggling and mixing up of particles and the attendant rise of entropy that governs steam engines and refrigerators." Particles fall toward massive objects not because of some mysterious attractive force but because configurations where they are closer have more microstates available.

Decision Framework

When to Consider Information-Based Gravity

Consider information-based gravity frameworks when:

Standard models fail to explain observations: Dark matter and dark energy remain mysterious in conventional physics. Entropic gravity naturally produces effects resembling both
Quantum-classical boundaries are relevant: Information-based approaches may provide natural explanations for why quantum superpositions collapse at macroscopic scales
Unification is the goal: Information theory offers a common language linking quantum mechanics, thermodynamics, and general relativity
Experimental precision reaches new thresholds: As measurement technology improves, the tiny effects predicted by these theories become testable

When Traditional Gravity Suffices

Continue using standard general relativity when:

Working at scales where relativistic corrections are small and well-understood
Engineering applications require proven, validated models
The system under study involves only classical mechanics with no quantum or thermodynamic subtleties

Practical Examples

Example 1: Carney's Qubit Model of Entropic Gravity

A recent model by Daniel Carney and collaborators provides a concrete example of how information gradients can produce gravity. They imagine space filled with countless quantum bits (qubits) that can be randomly oriented (high entropy) or aligned (low entropy).

When you place a mass in this medium, nearby qubits tend to align, creating a pocket of order (lower entropy) around the mass. Put a second mass nearby and it too polarizes qubits, making another low-entropy region. The rest of the medium wants to increase entropy, so there is a net push bringing the two ordered pockets closer together, merging them into one region and restoring randomness outside.

Outcome: This model recreates Newton's familiar inverse-square law of gravity as an entropic effect. The strength of attraction emerges naturally from the entropy gradient, without invoking any fundamental gravitational constant.

Example 2: Bianconi's Quantum Relative Entropy Framework

In 2025, Ginestra Bianconi formulated gravity as an emergent phenomenon arising from quantum relative entropy, essentially the difference in information content between the geometry of spacetime and the presence of matter. By treating the spacetime metric as a quantum informational object, her framework recovers standard general relativity under normal conditions.

Outcome: The model naturally produced a tiny positive cosmological constant (dark energy) without putting it in by hand. It also offers a perspective on dark matter as related to an additional "information" field in the equations, potentially explaining both cosmic mysteries through a single informational framework.

Example 3: Vopson's Mass-Energy-Information Principle

Physicist Melvin Vopson proposed a mass-energy-information equivalence principle. According to Landauer's principle, erasing one bit of information dissipates minimum energy of kT·ln2 (about 2.8 × 10⁻²¹ J at room temperature). By Einstein's E=mc², that energy corresponds to an effective mass of approximately 3 × 10⁻³⁸ kg per bit.

Outcome: A storage device wiping a terabyte of data (about 8 × 10¹² bits) would lose on the order of 10⁻²⁵ kg, around one hundredth the mass of a proton. While tiny, this suggests information itself is physical and contributes to mass-energy. Vopson proposed an experiment annihilating electrons and positrons to see if extra low-energy photons appear from erasing their information content.

Common Mistakes

Mistake 1: Confusing Decoherence with Emergence

Entropic gravity claims gravity emerges from information gradients, not that information merely affects gravity. The distinction matters: in the emergent view, without information structures, there would be no gravity at all.

Mistake 2: Expecting Immediate Technological Applications

While the implications are profound, the effects predicted are extraordinarily small. A picogram mass difference produces forces around 10⁻¹⁴ newtons at centimeter distances, near the edge of current detectability.

Mistake 3: Dismissing Null Results as Disproof

The equivalence principle has been tested to parts in 10¹³, but those tests compare different materials, not different entropy states of the same material. A subtler test comparing ordered versus disordered configurations of identical composition has not been explicitly performed.

Mistake 4: Treating the Holographic Principle as Proven

While mathematically elegant and consistent with black hole thermodynamics, the holographic principle remains a theoretical framework. Experimental confirmation requires technologies not yet available.

Proposed Experiment: Weighing Order vs. Disorder

A striking consequence of the information-density hypothesis is that two systems with the same rest mass but different internal entropies might generate slightly different gravitational forces. Orthodox physics says this should not happen, but emergent gravity opens the door to tiny violations.

Consider two lumps of matter, chemically identical and equal in mass but prepared in different states:

Lump A: A highly ordered single crystal with atoms in a perfect lattice, minimal defects, cooled to low temperature (low internal entropy)

Lump B: The same number of atoms in a randomized, amorphous arrangement or high-defect polycrystal, possibly at higher temperature (high internal entropy)

The experiment would suspend these in a sensitive torsion balance setup, introduce a source mass, and measure whether the torsion bar experiences differential torque. State-of-the-art Cavendish-style experiments can detect forces in the 10⁻¹¹ to 10⁻¹² N range, so improvements or clever amplification would be required.

If a robust difference in weight is observed between the two states, it would imply a violation of the equivalence principle at a new level, indicating gravity is sensitive to internal information content. A null result would place strong limits on information-based modifications to gravity.

Frequently Asked Questions

Does this mean gravity isn't real?

No. Gravity's effects are entirely real, regardless of whether it's fundamental or emergent. The question is whether gravity is a basic feature of reality like electromagnetism or an emergent phenomenon like temperature, arising from more fundamental underlying physics.

How does this relate to dark matter and dark energy?

Entropic gravity models have offered fresh explanations for both. If information density curves spacetime, what we call missing mass might be an emergent phenomenon rather than mysterious particles. Bianconi's framework naturally produces a cosmological constant matching dark energy observations.

Why haven't we detected these effects already?

The predicted effects are extraordinarily small. The mass equivalent of information is around 10⁻³⁸ kg per bit. Even scaling to macroscopic systems produces differences near the edge of current measurement capabilities. Moreover, most equivalence principle tests compare different materials rather than different entropy states of the same material.

Could this lead to practical applications?

Potentially, but not soon. If information configurations can alter gravitational effects, one could imagine gravity engineering at very tiny scales or new precision measurement techniques. However, the effects are so small that practical applications remain highly speculative.

Action Checklist

Review fundamental literature: Start with Bekenstein's black hole entropy papers and Jacobson's 1995 thermodynamic derivation of Einstein's equations
Study recent developments: Follow Carney's qubit models and Bianconi's quantum relative entropy framework for current theoretical directions
Understand measurement limits: Learn about torsion balance experiments and equivalence principle tests to appreciate experimental challenges
Consider interdisciplinary connections: Explore how quantum information theory, thermodynamics, and general relativity intersect in these frameworks
Design controlled experiments: If conducting research, focus on comparing entropy states of identical compositions rather than different materials
Monitor experimental results: Follow neutron interferometry, atom interferometry, and space-based gravity experiments for relevant data
Engage with cosmological implications: Consider how entropic gravity might explain dark matter and dark energy observations