# Do we want geosphere, biosphere, hydrosphere tags?

Simplified, Earth's systems can be broken up into four "spheres" that constantly exchange matter and energy with one another:

• The atmosphere, which includes all gasses around the planet
• The hydrosphere, which includes all of the planet's water and related systems
• The geosphere, which includes the all the material within and below the crust
• The biosphere, which is comprised of every living thing on Earth

We have , but why is it that the other 'spheres' do not have tags?
I suggest we make them, but some peer review would be nice.

"For questions about the gases which surround a planet or some other celestial body."
Current tag wiki. I think it's fine as-is.

"For questions about the liquids present on the surface of a planet and the associated systems."
Note that this is not synonymous with any other tag - in fact, very few tags cover this topic at all, yet multiple questions do (things like alien solvents and biochemistry, some weather patterns, erosion and landscape formation, chemical processes, and more). Examples include:

"For questions about the materials that compose a planet or other celestial body."
Related to and possibly synonymous; would be relevant to a plethora of existing questions that do not have the tag. Examples include:

"For questions about the ecological dynamics of a whole planet or celestial body."
Broader than ; related to the seldom-used ; more specific than ; more specific than . Examples include:

So what do you think? Are these tags relevant and/or reasonable? What changes would you make to them?

• Could you edit in links to some of the existing questions that you think should have these new tags? Thanks. – Monica Cellio Dec 1 '16 at 1:14
• Sounds like meta tags to me. – Vincent Dec 1 '16 at 1:25
• @MonicaCellio Done, although more posts are probably applicable under each tag – Zxyrra Dec 1 '16 at 1:57
• @Vincent Could you elaborate? (Potentially in an answer to this Q) – Zxyrra Dec 1 '16 at 1:57
• @Zxyrra thanks. I wasn't asking for an exhaustive list; just some representative samples. (Also to make sure there are some for each, because you can't create tags in advance of having questions for them.) – Monica Cellio Dec 1 '16 at 2:07
• What I mean is that we already have tags for hydrosphere (on the top of my head) river, water-bodies, ocean, underwater...If we created the hydro tag it would serve only to encompass already existing tags because it is pretty broad to begin with. – Vincent Dec 1 '16 at 3:49
• @Vincent Only "water-bodies" "underwater" and "ocean" exist; ocean has a single item. None of those encompass things like solvents, erosion, weather, chemical processes - for which "hydrosphere" would eliminate the need for multiple new tags. Additionally it's exactly as broad as atmosphere, which seems to work fine - "too broad" doesn't really apply to tags. – Zxyrra Dec 1 '16 at 4:06