On Saturday, August 8, 2015 at 9:56:39 AM UTC+1, Martin Brown wrote:

*Everything* radiates thermal energy according to Plank's law usually
approximating a black body according to its temperature.

https://en.wikipedia.org/wiki/Black-body_radiation
https://en.wikipedia.org/wiki/Stefan...3Boltzmann_law

Energy *transfer* between bodies varies according to the difference
between the fourth power of their absolute temperatures. Net energy flow
always being from the hotter to the cooler body.

The Earth's temperature ~290K is determined by being in thermal
equilibrium with one sun at 5500K subtending an angle of 0.01 radians
and ~4pi of empty space radiating at 4K (the microwave background).

Earth gains energy from the sun and thermalises it and loses energy to
the sky but nowhere is there any "cold radiation".

What about the microwave background at 4K. Can't we call it cold radiation?

Everything radiates thermal radiation to everything else in an amount
determined by its absolute temperature and surface emissivity.

However, holding a thermometer over an object taken from a freezer
will cause the temperature shown to drop.

Yes. Because the cold object below the thermometer is no longer
radiating at the same temperature as the rest of the surroundings. It is
the thermometer that is on average donating heat radiation to the cold
block which is not being returned any more in sufficient amount to
maintain its temperature.

Well, can't argue with what I haven't snipped.

But the reason the temperature on the thermometer drops is because the absorbed "cold" radiation is less than that which is emitted. The emissions are unchanged. It is the absorption from the cold radiation that causes the temperature to fall.

Just try to see why I am correct rather than searching for flaws.

Cheers, Alastair.