This is not exactly an English question, but it deserves some discussion. Maria wrote today to ask:
Is it true that one does not have to double space after a sentence in a paragraph or essay? When the piece is fully justified, does the spacing after punctuation matter? I was taught one space after a question mark and two after a period. My English teacher tells me that it no longer matters. In other words, I believe one would just single space after all punctuation. I have a hard time letting go of what I was previously taught. Please instruct me on the correct spacing.
In the days of the typewriter, every letter took up the same amount of space. An i occupied as much space on the paper as an m. This could make it hard to see if a period ended a sentence or simply meant an abbreviation in the middle of a sentence.
So the convention arose that two spaces would follow the period at the end of a sentence. And generations of typists, including me, got used to it.
But personal computers offered many different fonts, and letters took up different amounts of space. So, just as with printed text in magazines and books, it wasn't necessary to put two spaces after the end of a sentence.
Old habits die hard. It took me a couple of years to stop hitting the space bar twice at the end of every sentence. Some of my colleagues still put two spaces in. The result is text with oddly long spaces between sentences.
So when you're writing text on a computer, one space after a period (or question mark, or exclamation mark) is all you need.