Three-Body Lab is an interactive browser simulator of the classical three-body problem. It uses the same dark sidebar-and-canvas layout as the Physics Playground.

Configurations

• Figure-Eight: a stable periodic orbit where three equal masses share one curve (Moore 1993, Chenciner & Montgomery 2000).
• Lagrange Triangle: an equilateral arrangement that rotates rigidly. It is unstable with equal masses and stable when one mass dominates.
• Butterfly I: an unstable periodic orbit found by Šuvakov & Dmitrašinović in 2013.
• Pythagorean: Burrau’s problem. Masses 3, 4 and 5 start at rest, go through chaotic close encounters, and one body is ejected.
• Hierarchical: a star, planet and moon, showing how a close pair with a distant third stays stable.
• Random Start: random initial conditions that usually turn chaotic.

Features

• Ghost twin: a copy of the system nudged by a tiny amount (1e-6 by default). A log-scale graph tracks how fast the two copies diverge, which shows chaos directly.
• Edit mode: pause the simulation, then drag bodies to move them and drag the arrow tips to set their velocities.
• Controls: speed, trail length, gravitational softening, twin nudge size, and a mass multiplier for each body.
• Live readouts: time, energy and its conservation error, angular momentum, closest separation, steps per frame, and twin separation.
• Navigation: the view auto-fits by default. You can also zoom with the scroll wheel and pan by dragging empty space. Bodies that leave the screen get an edge arrow with their distance.
• Shortcuts: Space to play or pause, R to reset.

Physics: the simulator uses Newtonian gravity with G = 1 and a leapfrog integrator. The time step shrinks automatically when bodies come close. A short note in the sidebar explains the history: Poincaré showed that no general closed-form solution exists, so the problem can only be solved numerically.

SETI Cosmic Signal Listening Lab

An interactive radio astronomy experience that simulates how SETI researchers search for unusual signals hidden within cosmic radio noise.

Explore a dynamic 3D waterfall spectrogram, spectrum analyzer, and oscilloscope while listening to synthesized radio signals generated directly in the browser.

Use the built-in receiver and synthesizer controls to adjust frequency, bandwidth, noise, signal strength, volume, and scan speed, and observe how each setting changes both the sound and its visual representation.

The simulation is designed for educational exploration and uses synthetic signals rather than real extraterrestrial transmissions or live SETI observation data.

Four Fundamental Forces Explorer

An interactive science visualization that explores the four fundamental forces that govern interactions in the universe: the strong force, weak force, electromagnetic force, and gravity.

Explore how each force operates across different scales, from quarks and atomic nuclei to atoms, planets, stars, and galaxies.

The visualizer also compares their enormous differences in relative strength using a logarithmic scale, helping illustrate why the strong force dominates at nuclear scales while gravity, despite being extremely weak at particle scales, becomes dominant across astronomical structures.

An interactive science visualizer that explores how black holes move through space and interact with gravity.

Explore galactic travel, orbital motion, binary black holes, inspiral and merger, gravitational-wave recoil, gravitational lensing, and gravitational waves through real-time animated simulations.

Adjust motion speed, trajectory curvature, and trail length to observe how different motion patterns and gravitational interactions are visualized.

Designed as an educational astrophysics experience that helps users understand how black holes can travel, orbit, merge, distort light, and generate ripples in spacetime.

Dark Energy Hypotheses — 3D Visualizer

An interactive 3D educational simulator that explores possible explanations for dark energy and the accelerating expansion of the Universe.

Compare major hypotheses including Cosmological Constant, Quintessence, Modified Gravity, Phantom Energy, and Evolving Dark Energy.

Adjust dark energy density, matter density, equation of state (w), and cosmic time to visualize how different assumptions affect the expansion of the Universe.

The simulator also introduces the observational evidence, possible cosmic futures, and key concepts behind modern dark energy research.

The nature of dark energy remains one of the major open questions in modern cosmology.

Overview

A real-time interactive simulation of nuclear fission chain reactions in a U-235 reactor core. Neutrons travel across the canvas, collide with fissile nuclei, and trigger fission events that release energy and spawn new neutrons. The multiplication factor k is tracked continuously, and the reactor shifts between subcritical, critical, and supercritical states as parameters change. Four tabs cover the live simulation, chain reaction physics, reactor type comparisons, and a concept map.

Content

Reaction View — The main canvas renders U-235 nuclei, free neutrons with motion trails, fission flash bursts, and gamma-ray particles. Five boron carbide control rods descend from the top; a moderator grid overlays the field. A four-chip HUD displays live neutron count, total fissions, energy output, and k-effective. A criticality badge in the top-right corner switches color and label between Subcritical, Critical, and Supercritical as the reaction evolves.

Presets (4) — Power Reactor (4% enrichment, controlled critical), Prompt Critical (95% enrichment, no rods), Research Reactor (low power, subcritical), and SCRAM / Shutdown (rods fully inserted).

Parameters — Enrichment (1–100%), control rod insertion depth, moderator efficiency, neutron speed, and core density. Firing controls: single neutron, burst of ten, pause, and reset.

Right Panel — Six metric tiles (free neutrons, total fissions, energy in MeV, k-effective, U-235 remaining, total nuclei), a neutron population history chart, and three live mini-charts for energy output, neutron count, and k-effective over time. A criticality note updates with a plain-language explanation of the current reactor state.

Physics Tab — Six-step chain reaction sequence (neutron absorption → fission → prompt neutrons → moderation → control → criticality states) plus three data cards: fission energy (200 MeV), average neutron yield (ν ≈ 2.43), and U-235 thermal cross-section (585 barns).

Reactor Types Tab — Six designs compared: PWR, BWR, PHWR (CANDU), RBMK, Molten Salt, and Fast Breeder — each with moderator, coolant, enrichment level, and key safety characteristics.

Concept Map Tab — Six nodes from enriched fuel through neutron economy, mass-energy equivalence, delayed neutrons, thermal vs. fast neutron behavior, and defence-in-depth safety systems.

This is an interactive severe-weather laboratory designed to explore tornado formation, rotational dynamics, updrafts, wind shear, and debris motion from multiple perspectives.

• Live Vortex — Visualizes tornado circulation, funnel structure, and rotating particle flow in real time.
• 4 Visualization Modes — Explore the tornado through Vortex Flow, Debris Particles, Wind Vectors, and Pressure Field views.
• Formation Process — Follow the conceptual development sequence: Wind Shear → Strong Updraft → Tilt & Rotation → Stretching → Near-Ground Vortex.
• Storm Structure — Explore the relationship between Inflow, the Mesocyclone, and the Tornado Core within a rotating thunderstorm.
• Vortex Types — Compare different tornado appearances, including Rope, Cone, Wedge, Multi-Vortex, Rain-Wrapped, and Dust/Debris vortices.
• Interactive Environment Controls — Directly adjust Updraft Strength, Low-Level Wind Shear, Rotation, Moisture, Instability, and Vortex Width.
• Simulation Controls — Experiment with Spawn Vortex, Pause, Reverse Spin, and Reset.
• Real-Time Telemetry — Monitor Vortex State, Rotation Index, Core Pressure, Updraft, Shear, Vorticity, and Debris Count as the simulation runs.
• Rotating Updraft Visualization — Explore how a strong thunderstorm updraft can tilt horizontal atmospheric rotation into the vertical, helping create a rotating updraft.
• Vortex Stretching — Visualize how stretching and concentrating a rotating column of air can intensify its rotation.
• Concept Map — Understand the overall process: Warm Humid Air → Wind Shear → Rotating Updraft → Stretching → Surface Tornado.
• Educational Conceptual Simulator — This is not an operational severe-weather forecasting system. It is designed as an educational visualization for understanding the fundamental concepts behind tornado formation and dynamics.

The simulator provides an intuitive way to explore one of the atmosphere's most dramatic phenomena:

How can a rotating thunderstorm organize into a powerful tornado — and what happens inside the vortex?

Interactive Visual Simulator

What actually happens when a single neutron strikes a nucleus?

This interactive Nuclear Fission Chain Reaction Visualizer turns an invisible nuclear process into something you can see, control, and explore in real time.

Watch a neutron travel through the simulation, trigger a fission event, release new neutrons, and potentially start an expanding chain reaction. Then adjust the simulation parameters yourself and see how the entire system changes.

🔬 What You Can Explore

⚛️ Live Chain Reaction

Watch neutrons move between fuel nuclei as fission events occur. New neutrons are released, while others are absorbed or escape from the system — all visualized dynamically in real time.

🎨 4 Visualization Modes

Explore the same phenomenon from different perspectives:

Particle Cloud / Fuel Lattice / Radial Burst / Thermal Map

Each mode provides a different visual way to understand how a chain reaction develops.

📊 Criticality Explorer

See the difference between:

k < 1 → Subcritical

k ≈ 1 → Critical

k > 1 → Supercritical

Change the effective neutron reproduction behavior and immediately see how the neutron population responds.

⏱️ Generation Timeline

Follow the chain reaction step by step:

Incoming Neutron → Capture → Fission → New Neutrons → Next Generation

This makes it easier to understand how one microscopic event can lead to another generation of reactions.

🧠 Concept Map

Explore the fundamental ideas behind the simulation, including Fuel Nuclei, Neutron Population, Absorption, and Effective Multiplication.

🎛️ Interactive Controls

Experiment with parameters such as:

Fuel Nuclei / Neutron Reproduction / Absorption Tendency / Neutron Speed / Control Absorption

Then use Inject Neutron, Pause, Reset, and Absorb Neutrons to interact directly with the simulation.

📡 Real-Time Telemetry

Monitor Active Neutrons, Fissions, Generation, Absorbed Particles, Escaped Particles, and the changing Neutron Population Trend as the simulation runs.

🎓 Built for Learning

This is an educational conceptual simulator, not a real nuclear facility or reactor engineering model.

Real-world engineering parameters — including actual material compositions, enrichment levels, critical mass calculations, and reactor core geometries — are intentionally excluded.

The goal is simple:

Make the invisible visible — and turn nuclear physics into something you can explore interactively.