KiloCM does sound wrong, but it is interesting that we happily say "1,000 km", when we could say "1 Gm". Fashion and familiarity in that case. I need to rememb

KiloCM does sound wrong, but it is interesting that we happily say "1,000 km", when we could say "1 Gm". Fashion and familiarity in that case. I need to remember to say "it's 3.8 Gm from Seattle to New York".