this post was submitted on 26 Aug 2023
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Showerthoughts
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I know the metre has been defined by earth's size, or other various things, all rather arbitrary. Wouldn't it make sense to define it by the speed of light and a light year, divided into even portions? Start by dividing a light year (in a vacuum) by ten, and keep dividing by ten until we get a unit that is close to the useful size we are accustomed to?
That way we could scale up, and I suppose that's going to be useful in the future.
It's already defined that way - from Wikipedia "From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in a vacuum in 1/299792458 of a second. After the 2019 redefinition of the SI base units, this definition was rephrased to include the definition of a second in terms of the caesium frequency ΔνCs. "
Just because it's defined as some section of a light year does not mean it's using a light year as a reference. You could use a foot and find the fraction of a light year that represents it, but that doesn't mean that the foot is based on a light year.
I'm saying the short measure that we use on a daily basis might be a BASE 10 portion of a light year. Not 1/299792458 of a light second.
P.S. It's like being on Reddit, being download for conjecturing.
I see what you mean. That is just as arbitrary as using the Earth's size or any other reference. There's nothing special about a year.
Touché
My ignorance shows it's ugly face again.
it's a hard thing for me to wrap my head around, but it's cool when you think about it: there's actually no possible shared reference; even with atomic clocks, based solely on the bouncing of cesium atoms ticking away, the distance travelled is dependent on acceleration in your reference frame.
relativity really is!