Survey says...

[asterroc]

A few questions about terminology in astronomy... For any of the "Something else"s, I encourage you to comment. Or just in general, feel free to comment, though I'd appreciate it if you filled out the survey before you read the comments.

NOTE: third question didn't come out right, it's supposed to read "Are either the words 'size' or 'bigger' ambiguous to you?" If you care to add this in the comments, I'd love to know. :)

[Poll #1929305]

Comments

[q10.livejournal.com]

in reverse order, clarifications:

- had a job working as a research assistant doing something that would count as mathematics, for a guy employed in a philosophy department, a couple summers during college. have been employed as a TA or grader for a couple of CS courses.

- more 'vague' or 'polysemous' than 'ambiguous', it's not like the 'bank' (side of river) vs. 'bank' (financial institution), where there are distinct words that happen to be pronounced the same. it's just that the term is kinda fuzzy.

-for 'bigger than' it doesn't matter which of volume, radius, and diameter you use, since if it's bigger in one it's bigger in the other two, so there's no real way to distinguish.

-when people talk about 'size', either they're using it for comparison, in which case it's the same as 'bigger than' and it doesn't matter (unless they're talking about ratios), or they're probably going to name a specific size and otherwise give context in which case the way they're talking (and possibly just the units) will narrow it down. when the distinction matters and i can't tell from context what they mean (e.g. they say one planet is 'twice the size of' another), i probably assume they're talking 'volume', but without much confidence, and i ask for clarification if it's at all important.

-what does 'physical size' mean here, anyway? all the size concepts mentioned are in some sense 'physical', so defining 'size' as 'physical size' seems kinda circular and not especially elucidatory. i assume this is some kind of technical term in astronomy? does it mean something 2D like 'great circle area'? (this is a guess based on the fact that you've got 1D and 3D but not 2D size concepts in there.)

[q10.livejournal.com]

the vagueness here is something that's bothered me for a long time. like, i think most people would say that a 2 cup measure is twice the size of a 1 cup measure, which suggests volume, but on the other hand somebody would describe a 1/12 (linear dimension) scale model as being 'one twelfth the size' of the thing it's a model of, rather than 'one 1728th the size', which is what you'd get if you were talking volume. so it seems like we're just not consistent about this.

i'm trying to think of a case where it's area of a single surface, rather than volume or linear dimension, that matters, but the cases that come to mind are all things like sizes of different film formats (e.g. 35mm motion picture film frame is about half the size of 35mm still photography film frame), where it's intutively area that matters, but where volume scales with area (film thickness doesn't change with size of film frame), so there's no clear way decisively tell whether area or volume is the real thing that's being compared.

[sildra.livejournal.com]

I did an REU in astronomy the summer after my freshman year of college. It mostly involved modeling photoionization of neon (for the purpose of spectroscopy of stars), so on a couple different levels it only barely/technically counts as having worked in astronomy.

[hrafn.livejournal.com]

I realized looking at the lists of options that I do not think about this, generally, in that kind of specificity. I mean, if someone talks about diameter that also implies radius, and vice versa, right?

What does "physical size" even mean? Given how volume doesn't imply mass and vice versa. D: That /was/ my pick, for what I think, but now I realize I maybe don't know what -I- mean by that. >.<

I confess I rarely think about -mass- when people talk about size/bigness of planets. And so now I'm not sure how to mark the survey. Especially in the "one is bigger" category, since a planet can be bigger in volume but smaller in mass. *cries*

Ambiguous words are ambiguous.

I also haven't finished eating breakfast yet.

ETA: Having now read the other comments, I feel better about being confused/frustrated. I've definitely noticed that if people are talking -mass- (or weight) for an object, generally they make it clear, since in my experience, the only people talking about mass are talking within a scientific context, and so they are specific about that.