Which energy transfer would be absent without atmosphere?

• A. Convection would be absent.
• B. Radiation would be absent.
• C. Conduction would be absent.
• D. All energy transfer would stop.

Answer: (A)

Convection relies on a fluid medium to move heat through the bulk motion of that fluid. The atmosphere provides that fluid, so warm air near the surface can rise and be replaced by cooler air, creating a heat-transporting circulation. If there were no atmosphere, there would be no circulating air to carry heat away, so convection would not occur. Radiation doesn’t need a medium at all; it can transfer energy through empty space, so it would still happen. Conduction requires contact with matter, so heat can still move through solids or through any material that’s in contact, even without an atmosphere. The atmospheric convection pathway is the one that disappears.