In article <MARDER.117.2D29A1BB at agri.huji.ac.il> MARDER at agri.huji.ac.il (Jonathan B. Marder) writes:
>In article <2gbed2$sje at mserv1.dl.ac.uk> John Woods <eanv20 at castle.ed.ac.uk>
>writes:
>>And I'm still not sure whether
>>photons count as thermal energy or not.
>> ... John Woods
>>Photons definitely DO NOT count as thermal energy. Thermal energy is the
>*internal* energy of a substance which is due to vibrations/movements within
>the substance. You cannot have thermal energy in a vacuum, and photons
>definitely exist in a vacuum.
>Jonathan B. Marder '
>Department of Agricultural Botany | Internet: MARDER at AGRI.HUJI.AC.IL>The Hebrew University of Jerusalem | /\/ Bitnet: MARDER at HUJIAGRI
What happens if a thermometer is put in a vacuum that is bathed in
photons? Does the thermometer register a reading or not? (I think it
must do).
This assumes that an operational definition of thermal energy is by
the application of a thermometer.
H Sauro
