A recent announcement from NASA botches an attempt to show a distance in kilometres and miles, then goes on to give other data in miles only. Below, for your interest, is an excerpt from the announcement followed by my criticism and analysis of the situation, which I sent to NASA.
Bill Hooper Member, US Metric Association www.metric.org ============================================== On Mar 18 , at 12:33 AM, NASA News Services wrote: > Celebrating Mercury Orbit > Wed, 16 Mar 2011 23:00:00 -0500 > > ... The orbit insertion will place the spacecraft into a 12-hour orbit about > Mercury with a 200 124 mile (STET) minimum altitude. MESSENGER will be 28.67 > million miles from the sun and 96.35 million miles from Earth. Credit: > NASA/Paul E. Alers > There are two problems with your report the in Messenger spacecraft's orbit around Mercury: (1) It appears that you meant to write "200 km / 124 miles" but you neglected to enter the kilometres symbol after "200" Also, there was no separator between the two numbers to indicate that it was "one or the other". Therefore, it appears that you have announced that the minimum altitude was "two hundred thousand, one hundred and twenty–four miles" (200,124 miles)! Although Americans generally write that with the comma, many people use a space instead of a comma (200 124 miles), and most people recognize the space as being just a simple separator in a SINGLE, long number. and (2) While we are on the subject of units: Why is it so hard to tell us the distance to the sun and the distance to the earth in kilometres in addition to (or, better yet, in place of) the mile figure? The distance to sun and earth, respectively, can easily be written "46.13 million km" and "155.0 million km". Or one could take advantage of the simplicity of the SI metric system and report it as "46.13 Gm" and "155.0 Gm" (The symbol "Gm" stands for gigametres, where a gigmetre is one million kilometres.) While I admit that there are many people "out there" who are not sufficiently familiar with metric to understand what kilometre distance are (or megametre or gigametre distances), it is also true that there ALSO are many people "out there" who DO understand (and prefer) the simplicity of the SI system. You owe it to those people, too, to express your data in ways that they understand and prefer.
