I have found out that the reason for letting the photons in by the atmosphere and not letting 'em out - is the fact that the reflected photons have changed their wavelength and frequency.

 

Can anyone tell me how exactly that happens?

 

Thanks.

In as light, absorbed by the earth which radiates it out as heat.

Short wavelength photons ionize and dissociate molecules in the atmosphere. So short wavelength photons are absorbed, and their energy is converted to kinetic energy. Thus temperatures are high in the upper levels of the atmosphere.

wolfson said in post #3 :

Short wavelength photons ionize and dissociate molecules in the atmosphere. So short wavelength photons are absorbed, and their energy is converted to kinetic energy. Thus temperatures are high in the upper levels of the atmosphere.

 

thanks, but i was asking what's going on with the photon in the moment it hits the earth's surface. is it being reflected just in the same moment or rather absorbed and re-rediated later (when??). and finally when and how it changes to infrared (heat).

WikOne said in post #4 :

 

thanks, but i was asking what's going on with the photon in the moment it hits the earth's surface. is it being reflected just in the same moment or rather absorbed and re-rediated later (when??). and finally when and how it changes to infrared (heat).

 

Short wavelength photons pass through the atmosphere more readily, and are then absorbed be the earth. The earth radiates - this is blackbody radiation, since it has a temperature, and the molecules are vibrating - which is at a much longer wavelengths. The longer wavelength light doesn't pass through clouds readily.

 

Your characterization of IR=heat is incorrect. All EM radiation transfers energy. Hot objects tend to radiate strongly in the IR. But IR is not heat.