4 ms·
Eratosthenes did that in his time with spherical Earth model, and it was precise enough for ~2k years. A lot that can be hand waved with that route as opposed t
by numpad0 3y ago
Eratosthenes did that in his time with spherical Earth model, and it was precise enough for ~2k years. A lot that can be hand waved with that route as opposed to relying on availability of a well defined and calibrated precise time measurement device, whether it's 1 second or 2 minutes.
- defrost 3y agoEratosthenes who now? Sorry, couldn't help myself, unlike yourself. Just recall we're in a thread about precise definitions of reference units, the title posed refers to tens of trillions of oscillations as the definition of a second. When the kilometer was first coarsely defined by an Earth arc it was already a thousand+ years post shadow of a stick guy. Once that kind of definition gets refined further the "arc of the earth" approach hits all of the hurdles I outlined .. for the benefit of the person I replied to who somehow believed it was a simple straightforward task to make it "better". Hand waving a reference is all very well ... until you hit cases that require actual precision finer than the error bars on the hand wavy seat of the pants cowboy antics. That bar was crossed some decades past.