When not to hyphenate

One of my favorite errors to point out is an unhyphenated compound adjective. A compound adjective is when two words work together to modify a noun, and you need to connect those two words with a hyphen. If you leave out the hyphen, you get the first word modifying the second word, and this can lead to serious ambiguity. I wrote about missing hyphens recently here. Go look at the article—it contains examples. People don’t usually put in the hyphen if they don’t need it, but I found an unnecessary hyphen today. The article is interesting, too, if you like astronomy.

 By blowing a wind prior to exploding, the white dwarf was able to clear out a huge “cavity,” a region of very low-density surrounding the system. The explosion into this cavity was able to expand much faster than it otherwise would have.

You’re reading along, and suddenly you wonder, “a region of low-density what?” That hyphen told you “compound adjective here” so you expected a noun. Maybe you filled in the noun yourself—low-density vacuum. Or perhaps you re-arranged the whole sentence, “…a very low-density region surrounding…” Or maybe you picked the simplest  solution and removed the hyphen—a region of low density.

Perhaps some science writer has been reading this blog and got over-enthusiastic about hyphens. (I flatter myself. I’ve never gotten a comment from a science writer about anything.) Here’s the picture that goes with the article.

Four telescopes teamed up on this one

Oh—one other thing I need to be curmudgeonly about: Don’t write “prior to” when you mean “before.”