🌌 PyGalaxies

Watch celestial bodies collide and implode.

A real-time interactive galaxy simulator built with Python and Pygame. Models galaxies with thousands of stars, realistic gravity with softening, collisions, mergers, and core accretion—all in stunning real-time.

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🎯 Features

• Real-time N-body gravity simulation - Softening parameter and collision handling
• Core formation & accretion - Realistic physics for stellar accumulation
• Dynamic galaxy spawning - Generate and add new galaxies on demand
• Interactive camera - Zoom, pan, and explore at any scale
• Star trails - Visual history of stellar movement (toggleable)
• Simulation speed control - Speed up, slow down, or pause
• Live HUD - Real-time statistics, FPS, and control display
• Thousands of bodies - Configurable max star count for performance tuning

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🚀 Quick Start

Prerequisites

• Python 3.8+
• pygame
• numpy

Installation

pip install pygame numpy

git clone https://github.com/the-kitten-strikes-back/PyGalaxies.git
cd PyGalaxies
python main.py

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🎮 Controls

Key(s)	Action
SPACE	Pause/unpause simulation
R	Reset scene
G	Add a new galaxy
T	Toggle star trails
[ / ]	Decrease/increase simulation speed
+ / -	Zoom in/out
WASD or Arrow Keys	Pan camera
Mouse Wheel	Zoom

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⚙️ Configuration

Customize simulation behavior via the SimConfig class in main.py:

Parameter	Default	Description
width	1280	Window width in pixels
height	840	Window height in pixels
fps	60	Target frames per second
g	26.0	Gravitational constant (scaled)
dt	0.012	Simulation timestep
softening	7.0	Softening parameter for gravity
max_stars	2200	Maximum number of bodies
default_star_count	750	Stars per spawned galaxy
trail_alpha	28	Opacity of star trails (0-255)
collision_distance_factor	0.95	Collision threshold multiplier
core_accretion_scale	4.2	Core accretion radius scale
min_accretion_radius	10.0	Minimum accretion radius

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🔬 Physics Engine

Gravitational Softening: Prevents singularities and improves stability with very close bodies.

Collision Detection: Stars merge when they pass within the collision threshold, creating more massive bodies.

Core Accretion: Stellar cores grow by absorbing nearby material, creating realistic galaxy centers.

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💡 Tips

• Start with default settings to explore basic galaxy collisions.
• Increase max_stars for more detailed simulations (impacts FPS).
• Adjust softening to change how gravitational interactions feel.
• Reduce g for slower, more stable galaxy formations.
• Toggle trails (T) to see stellar orbital history.

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🛠️ Stack

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📜 License

Created by The Kitten. Free to explore, modify, and share.

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N-body simulation · Astrophysics · Real-time visualization