Event Horizon: This is the "point of no return" around a black hole. It's not a physical surface, but a boundary in spacetime. Anything that crosses the event horizon, including light, cannot escape the black hole's gravitational pull. In the simulation, it is represented by the central black sphere.
Accretion Disk: The glowing, turbulent disk of gas and dust that orbits the black hole. As matter gets closer, it speeds up and heats up due to friction, causing it to glow intensely. The brightness is not uniform; the side of the disk moving towards the observer appears brighter (Doppler beaming).
Spacetime Fabric: According to Einstein's theory of General Relativity, massive objects warp or curve the fabric of spacetime around them. This curvature is what we perceive as gravity. The simulation shows this as a "gravitational well," where the grid is bent downwards by the black hole's mass.
Gravitational Lensing: The black hole's immense gravity bends the path of light. This is why you can see a bright ring warping over the top and bottom of the black hole—it's the light from the far side of the accretion disk being bent into our line of sight.
Magnetic Fields & Polarization: The accretion disk generates powerful, twisted magnetic fields. These fields align light waves in a specific pattern, a property called polarization. The "Polarized Light View" simulates how telescopes like the EHT can map these magnetic fields by observing the polarized light, which appears as swirling patterns.