🌌 Solar System Simulator (Pygame, Physics-Based)

A fully-interactive, physics-accurate 2D Solar System simulation built using Python + Pygame. Bodies interact through Newtonian gravity, orbits are plotted over time, stars are rendered as a moving background, and the system architecture is fully modular.

This project implements real physics:

• G = 6.6743e-11
• AU scaling
• Velocity-based orbital motion
• Distance-to-sun display (light minutes / light seconds)

The codebase is cleanly divided into separate modules for maintainability.

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📁 Project Structure

solar-system-simulator/
│
├── main.py
├── parameters.py
├── colors.py
├── stars.py
├── solar_system_.py
├── create_bodies.py
├── simulation.py
└── README.md

Other options |-- RK4 - solar_system_RK4_NASA.py

📌 Module Breakdown

main.py

Runs the simulator:

• Initializes Pygame
• Loads stars & planets
• Handles pause / quit events
• Calls simulation & render functions
• Main game loop

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parameters.py

Stores all global configuration:

• Window size
• FPS settings
• Astronomical Unit (AU)
• Gravitational constant
• Pygame font loaders
• Time-step settings
• Constants used across the project

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colors.py

Simple module defining RGB colors:

BLACK = (0, 0, 0)
YELLOW = (255, 255, 0)
GRAY = (128, 128, 128)
YELLOWISH_WHITE = (255, 255, 246)
BLUE = (0, 0, 255)
RED = (188, 39, 50)

NAME_TEXT_COLOR = (111, 236, 123)
DIST_TEXT_COLOR = (56, 190, 255)

SUN_NAME_COLOR = (144, 128, 254)
SUN_TEXT_COLOR = (54, 32, 12)

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solar_system_.py

Contains the SolarSystemBodies class:

• Draw body & label
• Draw distance text
• Calculate gravitational force
• Update velocity & position
• Track orbit path
• Draw orbit path

Physics uses:

F = G * m1 * m2 / r²
v = v + a·dt
x = x + v·dt

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stars.py

Handles star field:

• Random generation of 400–500 stars
• Star colors randomized
• Efficient draw routine

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create_bodies.py

Creates actual solar system objects:

• Sun
• Mercury
• Venus
• Earth
• Mars
• (Optional) Moon
• Sets initial velocity for stable orbits

Example:

earth = SolarSystemBodies("Earth", BLUE, 1 * AU, 0, 5.97e24, 15)
earth.y_vel = -29.8e3

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simulation.py

Provides:

• update_bodies()
• Pause logic helpers
• Wrapper around body.update_position()

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🎮 Controls

Key	Action
SPACE	Pause / Resume simulation
ESC	Quit

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🪐 Features

✔ Real gravitational physics ✔ True orbital speeds ✔ Adjustable time-step ✔ Orbit trails ✔ Light-minute / light-second distance display ✔ Stars background ✔ Smooth motion at 60 FPS ✔ Modular architecture ✔ Easy to extend (add Jupiter, Saturn, Moon, etc.)

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🚀 Installation & Run

1. Install Python packages

pip install pygame

2. Run the simulator

python main.py