X is for X, the unknown variable
The other day Miss Landers was telling me about something she thought was really interesting. She had heard an explanation about how the unknown variable in algebra became symbolized by the letter X. She told me just enough to confuse me but also pique my interest. (Yes, we may be a little nerdy here.)
After poking around, I found a TED talk by Terry Moore that I think Miss Landers had heard.
In the talk, Moore explained algebra was developed by the Arabs, and in the original algebra text, the variables were called unknown things and that word started with the sh sound. Algebra made it to Spain and when the Moors translated it to Spanish, the sh sound became the ck because they had no sh sound. That was represented by the Greek chi, which was represented by X and later a small x in Latin. Or something like that.
While this is a nice theory, there are other opinions. First, others contend that there is no proof for the phonetic switch idea. They propose that the x symbol comes from DesCartes and his use of letters from the beginning of the alphabet (a,b,c) for known variables and letters at the end of the alphabet (x,y,z) for unknown variables. And as time went on and more things were printed, typesetters found it easier to use the x instead of y and z. Or something like that.
So if you haven't gone to sleep yet with these explanations on a topic that you aren't interested in, here's the part I found interesting. For some reason, even though I knew that x was used as the unknown as algebra, I never connected it as representing the unknown in other things.
x-rays-- Roentgen didn't know what he had, so he called them x rays
Malcomb X-- calls himself that for all of his unknown ancestors from Africa
X Files--They worked on strange cases with unknown origins
So I had a light bulb moment with this, and I'm going to put my new awareness to good use. I think dinner tonight will be known as Dinner X. :)