In many countries "1.6 billion kilometers" would be understood to mean "1.6 Pt" (petametres). If you use billion, trillion, quadrillion, etc. you risk being misunderstood in half the world."However, your use of "billions" should be relegated to the old customary units, as the term "a billion miles" means absolutely nothing to anyone other than "a long, long way"."Today in the 21st century we are all familiar with metric prefixes as we use them every day, e.g. kilo for "a thousand" (kilogram), milli for "a thousandth" (millimeter), Mega for "a million" (MegaHertz), cent for "hundredth" (cent coin), Giga for "a thousand million" (Gigabyte) and so on. "May I persuade you to consider using suitable prefixes for very large distances in order to make them more meaningful? Your statement "1.6 billion km" would be better stated as 1.6Tm (to use the correct terminology, i.e. Terameters), or at least you could use "xxx times the distance from the Earth to the Sun", or other suitable astronomical measuring terminology."
Term American meaning Euopean meaning
------ ---------------- ---------------
billion 10^9 10^12
trillion 10^12 10^18
quadrillion 10^15 10^24
"Billion" is a contraction of "bi-million".
If you will allow me to split a hair, those prefixes are mega, giga, tera, etc., not Mega, Giga, Tera, etc., It is their symbols that are an upper-case letter.
Joseph B. Reid
17 Glebe Road West
Toronto M5P 1C8 Telephone 416-486-6071
