# Is the second law of thermodynamics routinely violated?

**URL:** <https://boards.straightdope.com/t/is-the-second-law-of-thermodynamics-routinely-violated/833151>\
**Category:** Factual Questions\
**Created:** [April 28, 2019, 12:15am UTC](https://boards.straightdope.com/t/is-the-second-law-of-thermodynamics-routinely-violated/833151 "2019-04-28T00:15:23Z")\
**Posts on this page:** 1\
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**Author:** ![Max\_S](https://avatars.discourse-cdn.com/v4/letter/m/46a35a/32.png) [@Max\_S](https://boards.straightdope.com/u/Max_S)\
**Post date:** [April 28, 2019, 12:18am UTC](https://boards.straightdope.com/t/is-the-second-law-of-thermodynamics-routinely-violated/833151/2 "2019-04-28T00:18:49Z")

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> [@In Defence of Dualism](https://boards.straightdope.com/t/in-defence-of-dualism/832962/213):
>
> > [@In Defence of Dualism](https://boards.straightdope.com/t/in-defence-of-dualism/832962/210):
> >
> > > [@In Defence of Dualism](https://boards.straightdope.com/t/in-defence-of-dualism/832962/209):
> > >
> > > In fact, I suspect large-scale violations occur with relative frequency. If you have a 5000K star orbiting an 8000K star, the colder one will emit radiant heat that will be absorbed by the hotter one. The net heat flow will be toward the colder one, but the hotter still receives some heat from it.
> > 
> > Simultaneous heat flow from the warm star to the cold star or even radiation to outer space would qualify as “some other change, connected therewith, occurring at the same time”.
> > 
> > Even if you are using Carathéodory’s principle with Planck’s principle, there is still no violation. A (closed) system consisting of two cold stars in space is not adiabatically accessible from a system consisting of a warm star and a cold star in space. A warm star cannot turn into a cold star without suffering some transfer of heat or energy, either to the cold star or to space.
> > 
> > ~Max
> 
> Adabiasis is a system mechanism. It pertains to fluid movement. Stars do not primarily emit heat through fluid transfer, outside the internal convection zone within the star. Most heat escaping a star is radiative, in the form of IR and other photons. The radiated heat goes out in all directions (though possibly less at the poles), so a star will gradually cool at it sheds heat into space.
> 
> Stars come in many different flavors, some hotter than others, so it is not unusual to have a hotter/colder binary pair. A small fraction of one star’s radiative heat output will impinge on its partner, and vice versa. Hence, the colder star will move some of its heat to the hotter star, albeit less than the hotter star is moving to the colder star. A bunch of photons moving on a path are not deterred by a bigger bunch of photons coming the other way.

I’ve only heard of “adiabatic” in reference to a system where heat does not leave the system, and that was the meaning I used.

If you are describing a system consisting of a 5000K star orbiting an 8000K star, and you allow radiation to “leave” the system, then the second law of thermodynamics as formulated by Carathéodory (and Planck) does not apply. It is not violated; it does not apply to the system you have described.

If however, you include the surrounding space in the system, extending to infinity and encompassing all radiation emitted, then the second law of thermodynamics holds true.

~Max

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