Where does the Sun's influence end? This vertical explainer circles a code-built 3D heliosphere: a glowing shell with every planet inside, the termination shock Voyager 1 reached in 2004, the heliopause it crossed in 2012, and a readout showing it is now about 172 times farther from the Sun than Earth. Script, art direction, fact-check and QA by me; animation is code-driven 3D (AI-assisted, three.js); AI-generated Milky Way background; the Voyager close-up uses NASA's 3D model.