Switching measurement from kilometers to the light-year shifts the cognitive framework to measuring what?

How long it takes information or energy to traverse the gap (time).

The choice of astronomical unit profoundly affects human cognition and how scale is perceived. While using kilometers anchors the measurement to familiar, tactile terrestrial reality, switching to the light-year shifts the cognitive framework away from purely linear distance and toward the element of time. A light-year is defined by the distance light travels in one year, thus inherently linking the measurement to the speed of light. This temporal connection becomes highly relevant when studying light emitted from distant objects, as it provides an immediate understanding of the travel time of that observation rather than just the physical separation in space.