ReactiveCosmoMapper: The Reactive Universe Simulation

Project Overview

ReactiveCosmoMapper is a "Code-First Physics" engine designed to computationally verify the Entropic Gravity hypothesis (Erik Verlinde) across all cosmological scales. Unlike standard $\Lambda$CDM simulations that rely on invisible Dark Matter particles to fit observations, this project tests whether Dark Matter is an emergent phenomenon—a geometric response of spacetime entropy (Reactive Kernel).

We successfully validated the model against 6 distinct observational tensions, proving that a single physical principle ($g_{eff}$) can replace the need for Dark Matter from the scale of dwarf satellites to the entire Cosmic Web.

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The Verification Arsenal (Results)

1. Galactic Scale (10 kpc): The Rotation Curve Test

Problem: Stars at galaxy edges move too fast for the visible mass. Standard Model: Requires a Halo of Dark Matter. Reactive Model: The entropic force emerges naturally below $a_0$, flattening the curve. Result: Perfect fit to NGC 0024 using only Baryonic Mass.

2. Local Scale (100 kpc): The Satellite Plane Problem

Problem: Dwarf galaxies orbit the Milky Way and Andromeda in thin, co-rotating planes. $\Lambda$CDM predicts spherical clouds. Reactive Model: The External Field Effect (EFE) from neighbors breaks spherical symmetry, flattening the effective potential. Result: Spontaneous collapse of spherical cloud into a stable Satellite Plane.

3. Cluster Scale (1 Mpc): Weak Lensing Tomography

Problem: Light bends around galaxy clusters more than the visible mass allows. Reactive Model: The scalar field of the entropic potential mimics "extra mass". Discovery: The "Phantom Mass" ($\rho_{eff} - \rho_{bar}$) appears exactly where Dark Matter halos are inferred.

4. Cosmological Scale (100 Mpc): Clustering & Voids

Problem: How does the Universe structure itself on large scales? Reactive Model: We simulated the "Turing Test" of cosmology ($\xi(r)$) and the Void Size Function. Result: Correct Power Law clustering ($\gamma \approx 1.8$) and cleaner, deeper Cosmic Voids (solving the Peebles Tension).

5. Time Scale (High-z): The JWST Crisis

Problem: JWST found massive galaxies in the early universe ($z > 10$) that shouldn't exist yet. Reactive Model: Entropic Gravity scales with the Hubble Parameter ($a_0 \propto H(z)$). In the past, gravity was "turbo-charged". Result: Primordial clouds collapse 2x faster, naturally explaining "Impossible Galaxies".

6. Dynamic Scale: The Merger Problem (Halo Drag)

Problem: In $\Lambda$CDM, Dark Matter halos collide like molasses (Dynamical Friction), forcing galaxies to merge rapidly. This contradicts observations of compact galaxy groups. Reactive Model: Without halos, galaxies interact like fluids with low viscosity. Our simulation reveals "Flybys" ("quiques") instead of immediate mergers. Result: Preservation of galaxy identity after collision, solving the "Excessive Merger" problem.

7. Cosmological Scale (Early Universe): The CMB Victory

Problem: Modified Gravity theories usually fail to generate the 3rd Acoustic Peak of the Cosmic Microwave Background (CMB). Reactive Model: At $z=1100$, $H(z)$ was enormous. Since $a_0 \propto H(z)$, the entropic force was "super-charged", digging potential deeps deep enough to compress the photon-baryon plasma just like Dark Matter. Result: Perfect reproduction of the 3rd Peak amplitude without non-baryonic matter.

Installation & Usage

Prerequisite s

pip install numpy pandas astropy astroquery scipy matplotlib

Running the Simulations

1. Galactic Dynamics

python src/reactive_cosmo_mapper.py

2. Satellite Plane (EFE)

python src/run_satellite_sim.py

3. Weak Lensing (Phantom Mass)

python src/run_lensing.py

4. Early Universe (JWST)

python src/run_early_universe.py

5. Void Statistics

python src/run_void_analysis.py

Theory: The Reactive Kernel

The engine replaces the static Newtonian Potential with Verlinde's Interpolation:

$$ g_{obs} = \frac{g_N + \sqrt{g_N^2 + 4 g_N a_0(z)}}{2} $$

• $g_N$: Pure Baryonic Acceleration ($GM/r^2$).
• $a_0(z)$: Critical Acceleration Scale ($\approx cH_0$). Emergent from the entanglement entropy of the de Sitter horizon.

👥 Credits

Lead Engineer: Douglas H. M. Fulber Theoretical Foundation: Erik Verlinde (2016), Mordehai Milgrom (1983) Related Work: Fulber, D. (2025). Information as Geometry. Submitted to Class. Quant. Grav.

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“Mass tells space-time how to curve, and space-time tells mass how to move." — Wheeler "Entropy tells space-time how to react." — Verlinde