The title of the site is Earth Science, which implies questions should be limited to, well, Earth. But the term Geosciences may be considered a synonym, and the European Geosciences Union (EGU) does also cover planetary and space science. Should questions on topics such as,

  • Extraplanetary atmospheres,
  • Vulcanism on other planets, or
  • Extrasolar planets,

be considered on-topic on Earth Sciences?

  • 8
    $\begingroup$ AGU (agu.org) also heavily covers planetary science as well, for what it's worth. If it's within the realm of AGU, I'd argue it's on-topic here. $\endgroup$ Commented Apr 15, 2014 at 23:38
  • $\begingroup$ I think that this should be discussed with regulars of both Astronomy.SE and Space.SE. Sure there'll be an overlap, but only by cooperation the overlap can be minimized. $\endgroup$
    – yo'
    Commented Apr 16, 2014 at 20:02
  • $\begingroup$ Bringing this back to life somewhat. I've noticed that many questions on the Astronomy and Space Exploration stackexchanges that pertain to planetary sciences are going unanswered, but could probably be answered here. Is there someway we can notify people on those stackexchanges that their question may be more appropriate here? $\endgroup$
    – AlexLipp
    Commented Jun 25, 2014 at 8:17
  • 2
    $\begingroup$ @AlexLipp I don't know where you were looking, but on Space Exploration most questions tagged as planetary-science are not only answered, but have also an accepted answer. Earth Science has currently far worse statistics on planetary-science tag. I'm not trying to suggest anything, just setting the record straight. ;) $\endgroup$
    – TildalWave
    Commented Jul 20, 2014 at 7:38

5 Answers 5


Yes. All the physical processes on other planets are relevant to understanding our Earth. In fact, people who study the early Earth often interact significantly with people who study these processes on other planets. Also, planetary scientists, in general, interact more with geoscientists than they do with astrophysicists.

A good dividing line for planetary science questions is this: in which community is the topic studied more in: the astronomy community or the geoscience community? Exoplanet observation should be categorized as astronomy. Exoplanetary atmospheres is more borderline, but many people in planetary atmospheres are more geoscience than astronomy.

We also have to put in consideration the fact that the previous Astronomy SE died out, and the current Astronomy SE is having many of the similar issues that the previous one has.

  • 1
    $\begingroup$ "All the physical processes on other planets are relevant to understanding our Earth" - except, presumably, a lot of the processes on gas giants, and maybe other planets with very different structure. I still think that those processes should be included though - anything from the upper atmosphere down, on any celestial body that's not a star. $\endgroup$
    – naught101
    Commented Apr 28, 2014 at 0:48

As an actual planetary scientist here, I would say planetary science has always had this multilemma. Some of it is related to observational astronomy, some to space exploration, some to astrophysics, some to physical chemistry... but, in my opinion, the most interesting stuff is adapted geophysics, geochemistry, geology, and atmospheric science (and even hydrology, see Mars). This is the SE where I feel at home discussing planetary science.

  • 2
    $\begingroup$ +1 for teaching me a new "meta word"; multilemma, though no trace of lexicon SE now. $\endgroup$
    – uhoh
    Commented Mar 31, 2017 at 5:43

I would consider planetary sciences on topic. The site is intended for the study of the earth, that is OUR earth. But the study of other planets as "alternative" earths will help our own.

A possible exception to the rule is the study of other planets within constellations in "space." That becomes an "astronomy" issue that might not relate to earth science as we understand it.

Then again it might. The Astronomy SE site has a relatively weak following, and a lot questions on earth sciences aren't getting answered, and the solution might be a combined "Earth and Planetary" Science site.

I am writing this with an unusual background; an American liberal arts major whose exposure in school to science was in "general science." That's mainly earth science and astronomy, basically anything that wasn't biology, chemistry, or physics.


This kind of questions are common at worldbuilding. They receive attention, but not a lot. I have answered a couple of them (an example) as I find it interesting. The trouble I see is there are not a lot of users at worldbuilding to evaluate if the answer is correct, what does not happens on ES or physics/astronomy forum for atmosphere's physics related questions.

One asked at the chat before posting it here where, in my opinion, he received a better answer as it is a task for geologists, oceanographists or metheorologists, and not for videogamers or sci-fict authors.

So I think it would be better for ES and for the site in general if they migrate those questions here, but only if they are Science based and not fantasy worlds as an ocean with blood (as I found on worldbuilding).

  • $\begingroup$ I feel that while the question is on topic on Worldbuilding SE, the OP would be looking for a very different sort of response than they'd get on Worldbuilding. Specifically, whether something would work well in a story is very different from whether it would work in real life. $\endgroup$
    – Ed Grimm
    Commented Jun 23, 2019 at 16:11

It is my opinion that planetary sciences should be generally off topic so that this site can focus on the meaty questions about the Earth itself. Planetary science questions which deal heavily with Earth studies might be relevant though. Astronomy and Space Exploration both already cover planetary sciences, so there should be space already for those questions to be asked.

  • 3
    $\begingroup$ I think most people are disagreeing with this because this site is not about the Earth per se, but with processes that happen on the earth (in the earth, and a little way above the earth). Those processes probably all occur on at least some other planets. So as long as the questions are about those processes, it doesn't really matter what planet you're on. $\endgroup$
    – naught101
    Commented Apr 16, 2014 at 11:24
  • 5
    $\begingroup$ @naught101 I realize that. I think it is always healthy to have at least two contrasting views on these sorts of questions, and meta downvotes don't affect rep so I'll leave this up. I'm actually fine with this decision--that's why I stressed that this was my opinion. $\endgroup$ Commented Apr 16, 2014 at 12:28

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .