> On Mon, 24 Apr 2000 19:40:55 +0100, RC <email@example.com> wrote: > > >>In fact, a distinguishing characteristic between > >>"serious" and "recreational" astronomy papers is > >>whether they use parsecs or light years! > > Yes, I've noticed this - but is there any reason for it? I've never been > able to fathom why a unit based on the diameter of the Earth's orbit should > be superior to one based on its period of revolution. > ...
Historical mostly, many of the sciences tend to be very conservative, and historical conventions are very resilient.
Suppose you write an astronomy paper. To make sure the paper has a solid grounding, you have to cite references of work done previously. To make comparisons easier and to insure your paper is cited, it's best if you use the same units. If an astronomer way back used parsecs, cm & g, and his/her paper was very important, then any paper after that will use parsecs, cm & g.
Recreational articles don't have the same restrictions, they are intended for a broader audience, and will tend to use units that people can relate to - km, miles, AU, tonnes, suns, A-bombs, etc.