3 ms·
As of today, meter is defined in terms of the speed of light. We have come a full circle! > The meter is the length of the path travelled by light in vacuum du
by scorpion032 16y ago
As of today, meter is defined in terms of the speed of light. We have come a full circle!
> The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.
via: http://physics.nist.gov/cuu/Units/meter.html http://physics.nist.gov/cuu/Units/meter.html
- beza1e1 16y agoSo how long is a second?
- a1k0n 16y agovia Wikipedia: The duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom. So I guess that means a meter is 30.66331898849836976219 cesium-133 transition periods.