I understand that we have only eight planets now in our solar system, with the demotion of Pluto to "minor planet" status; that the map of the world has been redrawn numerous times in my lifetime and the Soviet empire collapsed of its own weight. Though irritated with the diminishment of Pluto's status, I am on board with all of these changes.
It is a radical change in modern punctuation that leaves me gasping. Having learned to type the old-fashioned way - using a typewriter - I grew up believing that a period is always followed by two spaces.
Apparently, I've been doing it wrong for a very long time. One is supposed to add just one space after a period.
From The Chicago Manual of Style Online:
The view at CMOS is that there is no reason for two spaces after a period in published work. Some people, however – my colleagues included – prefer it, relegating this preference to their personal correspondence and notes. I’ve noticed in old American books printed in the few decades before and after the turn of the last century (ca. 1870–1930 at least) that there seemed to be a trend in publishing to use extra space (sometimes quite a bit of it) after periods. And many people were taught to use that extra space in typing class (I was.)
But introducing two spaces after the period causes problems:
(1) it is inefficient, requiring an extra keystroke for every sentence;
(2) even if a program is set to automatically put an extra space after a period, such automation is never foolproof;
(3) there is no proof that an extra space actually improves readability—as your comment suggests, it’s probably just a matter of familiarity (Who knows? perhaps it’s actually more efficient to read with less regard for sentences as individual units of thought—many centuries ago, for example in ancient Greece, there were no spaces even between words, and no punctuation);
(4) two spaces are harder to control for than one in electronic documents (I find that the earmark of a document that imposes a two-space rule is a smattering of instances of both three spaces and one space after a period, and two spaces in the middle of sentences);
(5) two spaces can cause problems with line breaks in certain programs.
So, in our efficient, modern world, I think there is no room for two spaces after a period. In the opinion of this particular copyeditor, this is a good thing.
The Modern Language Association (MLA) weighs in:
Publications in the United States today usually have the same spacing after a punctuation mark as between words on the same line. Since word processors make available the same fonts used by typesetters for printed works, many writers, influenced by the look of typeset publications, now leave only one space after a concluding punctuation mark. In addition, most publishers' guidelines for preparing a manuscript on disk ask authors to type only the spaces that are to appear in print....
As a practical matter, however, there is nothing wrong with using two spaces after concluding punctuation marks unless an instructor or editor requests that you do otherwise.
Ah ha! Even with the MLA, this is an area of controversy. "Leave only one space after a concluding punctuation mark" - but "nothing wrong with using two!"
And confusion apparently reigns elsewhere. According to an About.com poll, of nearly 10,000 people polled, 47 percent favored two spaces; 43 percent favored one space; and eight percent of those polled voted to try and convince others to follow the one space rule.
Clearly, while most people tend to accept the new order of our universe as maps and solar systems evolve, when it comes to punctuation, closing down sentences with just one space has not achieved universal acceptance among users.
I may be old fashioned, but apparently, I'm not alone.