1 Note that this number is spelled differently from the trademarked name of a certain Internet search company.
2 A prime number is any number greater than 1 that is evenly divisible by only 1 and itself.
3 A joule is a measurement that describes energy or work.
4 Though of course the X-43A and other recent hypersonic aircraft have all been unmanned, so the Blackbird could still technically be considered the fastest airplane.
5 Actually, in some areas, the date line and the time zone lines diverge, so this isn’t always technically accurate.
6 You can refer to the table of prefixes and their abbreviations on the last page of this book.