Does Radiation from a Colder Body Affect a Hotter Body in a Vacuum?

[philrainey]

is it true that the radiation a colder body radiates through a vacuum will never hit a hotter body and have its radiation energy absorped? Is the radiation simply one way from the hot body to the colder body?

 

[tiny-tim]

Hi philrainey!

is it true that the radiation a colder body radiates through a vacuum will never hit a hotter body and have its radiation energy absorped? Is the radiation simply one way from the hot body to the colder body?

Nooo … they both absorb radiation from each other …

but the colder body always wins! ​

 

[DieCommie]

Remember that the hot emits more than the cold. So in the end there is still a net transfer from hot to cold, not from cold to hot.

 

[russ_watters]

The wording of the first sentence is very unclear to me...

Are you asking about two bodies sitting near each other in space? The hot object will radiate toward the cold one, but both will radiate away into space. Depending on the specifics of the situation, the cold one may still have a net loss of energy. Ie, the planets in the solar system have lost energy and cooled over billions of years despite getting energy from the sun. They radiate away more than they receive.

 

[philrainey]

The wording of the first sentence is very unclear to me...

Are you asking about two bodies sitting near each other in space? The hot object will radiate toward the cold one, but both will radiate away into space. Depending on the specifics of the situation, the cold one may still have a net loss of energy. Ie, the planets in the solar system have lost energy and cooled over billions of years despite getting energy from the sun. They radiate away more than they receive.

From what I understand you are right that hot body radiates heat to the cold body and both radiate to outerspace but the cold body also radiates a little portion of heat to the hot body but not as much as the hot body to the cold one.

 

[russ_watters]

Oh, well yes, it can be said that the cold body radiates toward the hot body and just receives more in return, yes. The net effect is it is receiving.