3 ms·
I remember that definition from high school. It's funny how useless that definition is, in that, knowing it doesn't help you figure out what it really is. The
by Timothee 17y ago
I remember that definition from high school. It's funny how useless that definition is, in that, knowing it doesn't help you figure out what it really is.
The newer definition: "In 1983, the metre was redefined as the distance travelled by light in free space in 1⁄299,792,458 of a second." always kind of bothered me because it sounds like it went like this:
"Ok, so we defined the speed of light as 299,792,458m/s and it's all over textbooks and formulas, but the thing is that our current definition of a meter sounds a little bit like a guess. So let's just reverse the speed of light and we're good!" It feels like a backronym to me (http://en.wikipedia.org/wiki/Backronym http://en.wikipedia.org/wiki/Backronym)
- clowdy 17y agometer was originally designed by French to be measured by clock which was much more precise at the time : a thread pendulum of length one meter has a period of two seconds . thatis why acceleration due to earths gravity is g~pi^2
- cromulent 17y agoI understood they designed it to be 1/10000000 of the distance from the North Pole to the Equator (through Paris). Then they had to calculate how far that was. They spent an awful lot of time and trouble measuring a large arc of the world by physical survey, but one of the guys made a small calculation error so it turned out later that the Earth is not exactly 40000km around. I read a book about it a few years ago, but I can't remember the title. Nautical miles are based on one minute of latitude, so they vary as the Earth is a bit squashed.