I don't think megameters are much used in metric countries, as opposed to thousands of kilometers. The circumference of the earth is almost always described as around 40 000 km, not 40 Mm. It is a perfectly respectable SI unit and should be used more often. Electrical engineers (I am one) like it. It is very handy when converting between frequency (in MHz) and wavelength (in meters), whether one uses rounded values such as 300 Mm/s, 299.8 Mm/s, or the exact value.
--- On Sun, 3/29/09, Teran McKinney <[email protected]> wrote: From: Teran McKinney <[email protected]> Subject: [USMA:44181] Re: The speed of light To: "U.S. Metric Association" <[email protected]> Cc: "U.S. Metric Association" <[email protected]> Date: Sunday, March 29, 2009, 9:04 AM I like to think of the speed of light relative to the total distance travelled in your car. 300Mm~ isn't too uncomon to see on some odometers. If after driving a car for 15 years you hit 300Mm, you've travelled the distance that light passes in one second :-). In properly metricated countries, do most people use Mm or something like "thousands of km" to show distance to Mm accuracy? I think that it seems like a very handy unit. Cheers, Teran PS: In a church service recently someone was giving a statistic that the odds of something were 1^167 or something. I corrected him saying that it was 1*10^167, but I'm not sure if he understood the real difference. Powers of 10 are fun :-).
