From Newton to Entropic Gravity: The Evolving History of What Pulls Us Down

Introduction: Is Gravity Really What We Think It Is?

For centuries, gravity has been one of the most mysterious yet familiar forces in nature. We drop an apple and watch it fall; we orbit the Sun thanks to gravity's pull. But is gravity truly a fundamental force of nature? Or could it be something more surprising—like a consequence of thermodynamics and entropy?

In this post, we’ll explore the remarkable journey of gravitational theory—from Newton’s elegant equations to Einstein’s revolutionary spacetime—and dive into the boldest modern idea yet: that gravity might just be an emergent phenomenon arising from disorder. Let’s take that fall down the rabbit hole together.

Newton’s Gravity: The Force That Started It All

Isaac Newton introduced the concept of gravity as a force between two masses, described by the famous inverse-square law:

"Every particle attracts every other particle in the universe with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers."

 

This law explained everything from falling apples to planetary orbits. However, Newton never explained how the force acted across space. Even he admitted discomfort with this “action at a distance.” Yet, for nearly 250 years, Newton’s laws ruled celestial mechanics. His work laid the foundation for classical mechanics and gave rise to the belief that the universe operated like a giant clock—a predictable machine governed by clear mathematical laws. But as our understanding of the universe deepened, cracks began to appear in this mechanical picture.

Einstein’s Gravity: Spacetime Bends

 

In 1915, Albert Einstein shattered the Newtonian picture with his theory of General Relativity. Rather than a force, gravity emerged from the geometry of spacetime. Massive objects like stars and planets bend spacetime, and other objects simply follow the curved paths—called geodesics—within it.

This theory not only redefined gravity but made bold predictions: gravitational time dilation, light bending around stars, and the existence of black holes. All of these have been experimentally confirmed. Gravity, it seemed, was the shape of the universe itself.

Einstein’s equations are elegant but complex. They describe how energy and momentum determine the curvature of spacetime, and in turn, how that curvature dictates the motion of objects. This view of gravity is deterministic and geometric—but not necessarily final. New developments in thermodynamics and quantum theory have added deeper layers to the mystery.

Black Holes and Entropy: A New Clue

 

In the 1970s, physicists like Jacob Bekenstein and Stephen Hawking discovered that black holes aren’t just gravity traps—they have entropy and temperature. This suggested a profound connection between gravity, thermodynamics, and quantum theory.

Hawking’s famous result showed that black holes radiate like hot objects—a phenomenon now known as Hawking radiation. This opened a doorway to thinking about gravity in terms of entropy: a measure of disorder.

This realization was a turning point. If black holes could be thermodynamic systems, then perhaps spacetime itself has microscopic degrees of freedom—much like atoms in a gas. Could gravity then be a large-scale statistical effect of these unknown microscopic components?

Jacobson’s Thermodynamic Gravity (1995)

Building on this, physicist Ted Jacobson proposed in 1995 that Einstein’s field equations—the very heart of General Relativity—could be derived using the laws of thermodynamics. In his model, spacetime behaves like a thermodynamic system, and gravity emerges from entropy changes across microscopic “horizon patches.”

This was a bold shift: instead of starting with geometry, Jacobson started with heat, entropy, and information.

This idea echoed the earlier realization that temperature and pressure are emergent properties. Just as heat arises from atomic motion, could spacetime curvature arise from the statistical behavior of some deeper quantum constituents?

Verlinde’s Entropic Gravity (2010): Gravity as Information Flow

In 2010, Dutch theoretical physicist Erik Verlinde took this idea further. He proposed that gravity is not fundamental at all—it’s an emergent entropic force. In his model, when matter moves, it disturbs the underlying information structure of space, and this shift leads to what we experience as gravity.

To explain it simply, think of how particles in a shaken box tend to cluster—a phenomenon called the "Brazil nut effect". The large nuts (mass) appear to rise or fall due to entropic dynamics, not a fundamental push or pull. Verlinde suggests something similar might be happening with planets and stars.

To explain it simply, think of how particles in a shaken box tend to cluster—a phenomenon called the "Brazil nut effect". The large nuts (mass) appear to rise or fall due to entropic dynamics, not a fundamental push or pull. Verlinde suggests something similar might be happening with planets and stars.

Verlinde’s theory also attempted to explain galactic rotation curves—typically attributed to dark matter—without invoking any unseen particles. Though controversial, this interpretation provided an alternative lens to view longstanding cosmic puzzles.

Recent Developments: A Thermal Medium Behind Gravity?

More recently, researchers like Daniel Carney and colleagues have proposed models where a “thermal medium” permeates space and interacts randomly with particles. This interaction gives rise to behaviors that look like gravity—but without invoking fundamental gravitational fields.

These models aim to make the theory more concrete—and perhaps even testable. Could gravity just be the result of deeper microscopic randomness? Could entropy be what’s truly pulling us down?

If these ideas are correct, gravity could be a side effect of entropy increasing in an invisible quantum field—a field we do not yet understand but may one day be able to detect or manipulate.

Criticisms and Open Questions

While intriguing, entropic gravity remains controversial. Some physicists argue that the forces described aren’t truly the same as Newtonian or Einsteinian gravity. Others are working to refine the models and propose experiments that could detect subtle differences.

Open questions include:

• Does entropic gravity predict everything General Relativity does?
• Can we experimentally test these models?
• How do we integrate entropic gravity with quantum mechanics?
• Can we build a laboratory analog of spacetime as an emergent thermodynamic system?

While intriguing, entropic gravity remains controversial. Some physicists argue that the forces described aren’t truly the same as Newtonian or Einsteinian gravity. Others are working to refine the models and propose experiments that could detect subtle differences.

Why It Matters

If gravity is emergent, it could unify thermodynamics, information theory, and quantum physics in one elegant framework. It could change how we think about space, time, and matter. And it could offer new insights into mysteries like dark energy and dark matter—both of which remain poorly understood within conventional gravity theories.

This perspective also reshapes our understanding of the universe’s origins and fate. It could influence how we interpret cosmic inflation, the arrow of time, and even the structure of spacetime itself.

This perspective also reshapes our understanding of the universe’s origins and fate. It could influence how we interpret cosmic inflation, the arrow of time, and even the structure of spacetime itself.

Conclusion: A Force Born of Heat?

From Newton’s apples to Einstein’s curved spacetime, and now to entropy-driven theories, gravity continues to evolve in the minds of physicists. We may be on the cusp of understanding not just what gravity does—but why it exists at all.

If these emergent models are correct, gravity may not be pulling us down. Instead, the universe might be nudging us toward disorder—a subtle thermodynamic whisper encoded in the fabric of reality itself.

What do you think? Could gravity be just a reflection of rising disorder in the universe? Or is it something deeper still? Leave your thoughts in the comments below!