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When discussing a rocky planet, is there any terminology to distinguish that you're talking about the whole thing, including the atmosphere, veruses that you're talking about the ocean + crust + mantle + core as a separate thing from the atmosphere? Or do you have to depend upon context to make that distinction?

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About the only time it could make any difference is when considering impacts on the planet. In that case, if a body enters the atmosphere, it is considered to have impacted the planet. For example the dust sized particles that form meteors don't reach the surface of the Earth, yet are still considered to have impacted the Earth.

On the other hand, quoted sizes of diameters normally don't include the atmosphere since the top of the atmosphere is fuzzy, and varies with temperature. For exoplanets, none of this matters since we don't have anything like enough resolution to determine atmospheric depth, or even the presence of an atmosphere in many cases.

Remember that gas giant planets don't have a solid surface. The cloud tops are then used as a proxy for the surface.

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  • $\begingroup$ It can make a difference if you're talking to one of those "Electric Sun" or "Electric Universe" people who bring electrical charges into everything. Trying to discuss things with them can be headache inducing enough even if both sides are using the correct terminology. $\endgroup$
    – Matthew Cline
    Sep 11, 2016 at 16:52
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Planet means usually the whole thing, as far as I'm aware. Then there are specialized terms for what you've suggested:

  • Cryosphere when talking about ice only
  • Hydrosphere when it concerns water
  • Lithosphere when talking about the crust that is still solid rock
  • (there are more terms for soil, geology, atmospheric substructure...)

But all those terms have an obvious relation to the construction of the word 'atmosphere'. The only term I've heard for 'Earth minus atmosphere' is 'bulk Earth'.
Those terms should be context free, so that you can directly, precisely refer to them when starting a conversation about them.

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