Final answer:
Sun radiation is transferred to Earth's atmosphere through radiation, a process that does not require a medium and involves the emission of electromagnetic waves that are absorbed by Earth.
Step-by-step explanation:
Radiation from the sun spreads throughout Earth's atmosphere primarily through radiation. Unlike conduction, where atoms or molecules pass energy through collisions, or convection, where warm material circulates conveying energy, radiation involves the movement of energetic photons through space. Earth receives this energy as electromagnetic radiation, which does not require a medium to propagate. Thus, heat from the sun is transferred across the vacuum of space and is then absorbed by various elements of Earth's environment, warming our planet.