Per a style manual (custom, but largely based on CMS), I’m capitalizing the Sun and the Earth (as opposed to a sun or a clump of earth). Nothing fancy there.
But I have the following sentence:
Explain that “helio” means sun; “geo” means Earth and “centric” means centered.
While part of me is satisfied and wants to move on, part of me says, “waitasecond… we talk about the geology of Mars, so geo isn’t necessarily referring to the Earth”. Any thoughts?
I have always capitalized the names when using them as names (i.e., if you could substitute Sol for the Sun and Terra for the Earth). Any chance of re-writing the sentence to say “Explain that ‘helio’ refers to the Sun; ‘geo’ refers to the Earth and ‘centric’ means ‘centered’”?
Excellent suggestion, thanks.
Sidestepping aside, what if the sentence had to remain as is with the exception of capitalization?
Uncapitalize Earth, IMHO.
In a short story set on Mars, Robert Heinlein used the terms “areology” and “areography”. It does not seem to have caught on. I have no idea what term a professional astronomer would use, but I suspect most other people would prefer “geology” and “geography”.
As for whether or not to capitalize, it seems to me that it depends on the emphasis the sentence places on it.
“He travelled around the earth in 80 days.” Emphasis on the fact that he was travelling.
“He travelled around the Earth in 80 days.” Emphasis on where he was travelling.
“The moon rose.” Emphasis on something rising, darkness being lightened.
“The Moon rose.” Emphasis on the fact that it is the Moon, rather that the Sun or a star.
Without knowing the context of the sentence, I am inclined to agree with KneadToKnow
The term “sun” means that star close enough (and presumably around which one’s reference point is orbiting) to provide light and heat in measurable quantities. The word “Sun” means the star around which our own planet orbits. Likewise “moon” means second-order satellite, one which revolves around a planet rather than a star. Jupiter has a scad of moons including Ganymede, Io, Europa, and Callisto. “Moon” means the sole natural satellite of Earth. Earth is the oddball in this sequence; it means either “soil” or “oxide” depending on whether you are talking natural history or chemistry/geology. Very rarely it is used to mean “earthlike planet.” I disagree with Knead to Know; reference to Earth as a planet should be capitalized-- though I’ve seen the uncapitalized earthlike and related forms, e.g., earth plants as opposed to the hypothetical natural vegetation of another earthlike planet.
As noted above, it was the custom for much of the 20th Century among a substantial part of those with an interest in making the distinction to use Sol, Terra, and Luna, the Latin terms for sun, earth, and moon respectively, to refer to the Sun, the Earth, and the Moon. Anyone conversant with Heinlein’s fiction will find the usage familiar; it was not his coinage but the standard he grew up with as he learned astronomy, etc. It seems to have faded from common use in the 1970s or so.
Selenography and selenology are commonplace uses for “lunar geography” and “lunar geology” respectively; as noted, areology and areography do not seem to have caught on for Martian geology and geography.
Indeed, I know no areologists, but many Mars geologists. Also, there is some dispute over whether the adjective M/martian should be capitalized— a certain NASA style guide says no (since terrestrial isn’t capitalized, and it refers to Terra, likewise. . .), but others, including most spellcheckers, insist on it. I prefer the non-capitalized version, just because I think it looks cleaner on the page when used frequently in a paper. Note I’m only commenting on the debate among planetary scientists, I have no idea how grammarians weigh in.
I would say that both should be capitalized, in that example. Although the term “geology” has come to encompass minerals on any celestial body, the root does still refer to our own planet specifically.
Does any style guide support MBH’s distinction based on emphasis? CMS and the various customized style guides I use would capitalize throughout his (?) examples. I agree, since Earth and Moon are being used as proper nouns. I wouldn’t write Last year, rhythmdvl traveled around the earth in 80 days to keep the emphasis on traveling.
Following Chronos (that sounds like a good book title, no?) there is a contextual reason for capitalizing both in the original example. The overall discussion is about helio- and geocentric models of the solar system, so the prefixes are definitely referring to the Earth and Sun.
I love this place. I love that in a question about grammar, people refer not just to planetary scientists, but to planetary scientists they know.