This example visualizes the orbital hierarchy of the solar system using animated circles positioned along a horizontal axis, ordered by planetary distance from the Sun. Each planet and the Sun appear as scaled circles with distinct colors, while text labels fade in sequentially beneath each body. The implementation uses D3.js v7 selections with `transition` and `easeLinear` to grow entering circles from radius zero, shift existing positions with fast transitions, and fade out exiting elements. Data is hardcoded in the script, with coordinates derived from astronomical distances and radii scaled to the container dimensions.