I rounded off Part 3 of this series by suggesting the following:

“Next up: How do you heat a planetary surface, then? If not by the Earth’s own thermal radiation, a result of its temperature rather than a cause of it … How does the atmosphere insulate the surface?”

Not so. This will have to wait a bit still. Next post, perhaps. I will rather try to clarify my stance on the whole ‘bidirectional flow’ concept thing, seeing how this topic has a tendency of stirring up both emotions and misconceptions.

There is quite a bit of confusion surrounding the whole issue of electromagnetic radiation, the Stefan-Boltzmann Law and the thermodynamic concept of ‘energy transfer’.

I will try to explain why there can be no such thing as a bidirectional energy transfer between two objects radiating at each other. Yes, they are radiating at each other! Radiation goes in all directions. Continue reading →