Someone wrote and asked me about some of the numbers in my previous post. One of the best things I've done awhile is start up a spreadsheet of the various numbers, constants, factors and quantities I find useful and/or interesting.
I started it, I think, after I got tired of looking up the Earth's surface area for about the tenth time. In college I had all the fundamental constants memorized, but, alas, some of those have gone just from lack of use. (And some have just been set equal to 1.)
In the spreadsheet, numbers in blue are inputs from the listed source, and numbers in black are the result of a conversion or calculation.
What can I say?--I like numbers. And I don't feel like I really understand something until I get a handle on them. (But at the same time, in the era of spreadsheets, one has to guard against applying worksheet functions without thinking about, or understanding, what you're really doing.)