Re: Heat in Space Re: Objectionable material for children

[Andrew Crystall]

On 10 Feb 2001, at 13:17, John D. Giorgis wrote:

> At 08:21 PM 1/24/01 -0600, Erik wrote:
> >On Wed, Jan 24, 2001 at 07:14:45PM -0500, John D. Giorgis wrote:
> >> Wait a second!   Can a vacuum *have* a temperature?   I thought
> >> temperature was based on atomic vibrations ~ or something roughly
> >> to the effect. Since a vacuum is empty, how does it have a
> >> temperature?
> >
> >I don't have time for a complete answer, but here's something to
> >think about. Suppose you are in space, in a vacuum. Can you measure a
> >temperature difference if you can see starlight or if you are in
> >complete darkness? There are no atoms in either case.
> 
> True..... obviously even in a vacuum, the closer I get to a star, the
> hotter it will be.   Just look at Earth vs. Mars.
> 
> So, EM Radiation stimulates molecules to generate heat?

There are three forms of heat generation...

conduction, convection and radiation

Of those, ONLY radiation works in a vacuum....

Andy
Dawn Falcon