Module 1: Perspectives


Dr. Elizabeth Roettger

By international agreement:

  • 1. The primary language of astronomy is English.
  • 2. The International Astronomical Union (IAU) is responsible for determining the official names of astronomical objects.

Most astronomical journals are published in English, and most international conferences and workshops are conducted in English, although significant work is also presented in other languages, such as French, German, and Japanese. This is even more apparent in planetary science (a field of astronomy, but with additional roots in physics, chemistry, geology, and atmospheric science); in planetary science, American English currently dominates.

The IAU Style Manual recommends that astronomical objects be treated linguistically as proper nouns. This means we capitalize Sun (our local star), Earth (our planet), Moon (Earth's natural satellite), and Solar System (ours). Further, these words are not proceeded by "the" any more than we would say "the Jupiter". This use is consistent with Betelgeuse (a star), Neptune (a planet), Titan (a moon of Saturn), P/Halley (a periodic comet), and 1 Ceres (an asteroid), Milky Way (our galaxy), and Universe (the only one we know for sure). I know saying "Sun" instead of "the sun" can be awkward, but there are ways of working it, such as saying "our Sun".

The use of "moon" to refer to natural satellites other than Earth's satellite is a general term and not capitalized. The same is true of other suns (although "other stars" is more accurate) and other solar systems (or "stellar systems" -- especially since many have two stars in the system). When not referring to Sun, Earth, and Moon as astronomical objects, the above guidelines don't necessarily apply. For example, if I'm talking about lights in the sky, I may say "the sun rose" or "the moon was full". Perhaps the whole earth would be grateful for an end to famine; I also dig in the earth (dirt or soil) when I'm gardening.

Most American style manuals, particularly those of newspapers and non-scientific journals, still specify use of "the sun" and such, even when referring to astronomical objects. For this course, the IAU style is preferred, but both styles are acceptable. In formal writing (study guides and lesson plans), please use one style consistently.

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