We do not yet have a postcard-quality portrait of YR4. Even to the James Webb Space Telescope, it appeared as a tiny point of light. But light can carry a surprising amount of gossip.
By comparing reflected sunlight with infrared heat, researchers estimated YR4’s size and learned something about how its surface behaves. NASA reported that the exterior may be dominated by rocks about fist-size or larger.
Picture a lumpy pile of charcoal-colored rubble rather than a smooth billiard ball. That remains an informed sketch, not a confirmed portrait. The 2032 approach will bring better viewing geometry, but for now astronomers are doing the cosmic equivalent of identifying a distant campfire by its glow.