Because we tried to make the meter one 40-millionth of the earths circumference, failed, and ended up at a 299792458th of the distance light travels in a 60th of a 60th of a 24th of the time earth doesn’t take to make a full rotation.
Having said that, we’re pretty lucky that using those pretty arbitrary values we ended up with a speed that you can approximate as 300 million m/s and be off by less than 0.1%.
My understanding is that the person proposing the meter’s distance immediately caught their mistake but didn’t bring it up because they didn’t want people to think the system was flawed, not so much that the measurement was off.
At least one second has a simple origin, and totally wasn’t back-defined in 1967
oh wait
The current and formal definition in the International System of Units (SI) is more precise:
The second […] is defined by taking the fixed numerical value of the caesium (Cs) frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the Cs-133 atom, to be 9192631770 when expressed in the unit hertz, which is equal to s−1.[1]
Because we tried to make the meter one 40-millionth of the earths circumference, failed, and ended up at a 299792458th of the distance light travels in a 60th of a 60th of a 24th of the time earth doesn’t take to make a full rotation.
This one’s on us
Well, in our defense, we’re very small.
Ent verified, ent approved
Are you sure?
Having said that, we’re pretty lucky that using those pretty arbitrary values we ended up with a speed that you can approximate as 300 million m/s and be off by less than 0.1%.
My understanding is that the person proposing the meter’s distance immediately caught their mistake but didn’t bring it up because they didn’t want people to think the system was flawed, not so much that the measurement was off.
At least one second has a simple origin, and totally wasn’t back-defined in 1967
oh wait
The second […] is defined by taking the fixed numerical value of the caesium (Cs) frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the Cs-133 atom, to be 9192631770 when expressed in the unit hertz, which is equal to s−1.[1]