How could SI units be derived from scratch without the use of modern technology?
How could SI units be derived from scratch without the use of modern technology?
Think "you wake up in the woods naked," Dr. Stone-style tech reset. How could humans acquire a 1-gram weight, a centimeter ruler, an HH:MM:SS timekeeping device, etc. starting with natural resources?
My best guess was something involving calibrating a mercury thermometer (after spending years developing glassblowing and finding mercury, lol) using boiling water at sea level to mark 100 ° C and then maybe Fahrenheit's dumb ice ammonium chloride brine to mark -17.7778 ° C, then figuring out how far apart they should be in millimeters on the thermometer (er, somehow). I can already think of several confounding variables with that though, most notably atmospheric pressure.
I feel like the most important thing to get would be a length measurement since you can then get a 1 gram mass from a cubic centimeter of distilled water.
That's as far as I got with this thought experiment before deciding to ask the internet. I actually asked on Reddit a while back but never got any responses.
You're viewing part of a thread.
I'm personally not voting on your comments, but you are probably being down voted because you are either being purposefully ignorant or you are continuing to insist on a "better system" that is physically impossible.
How is a better system impossible? Lets say you are on a star ship, heading away from earth, no reference points besides distant stars. How do you determine time? How do you determine anything? Even if we knew and simulated exactly how fast the earth is spinning and how much it is rotating around the sun, it means nothing out there. We have decided that time works the way it does, all I am asking is to take the extra .24 days in a year and make them disappear. There are several inconvenient ways to do this but it is possible to break it down further so we do not need the extra day. We could round it off to the nearest day every few years, shrug our shoulders and move on with our lives without tacking on another 29th day in some random month? Maybe there is some other way we haven't thought of? I guess I just thought more people would respond positively to "impossible future scenario where a calendar that makes sense is used" :/
Sure, in that scenario, such a system would be possible. Hopefully, there is still an earth to communicate with however. So we'd have to keep using earth days and years to enable effective communication. Also, the entire ship would have been built using earth based units, so it might be easier to use the system we've already got.
We're not on a space ship though. We're on Earth, so what happens on this planet matters. You may care more about not having leap years, but the majority of us care about knowing approximately what the weather will look like at a given point in time and how much sunlight to expect, since those things actually affect our daily lives, whereas an extra day in a given month does not.
What about when in the future if we needed to, say, sync time between here and mars, it would make it easier if we had some "frame of reference" outside of the sun maybe. There would basically just need to be a slight redefinition of what a day is, to account for the extra quarter of a day each year, its only a minute each day, ~86,460 seconds in a day instead of 86,400. Not exactly gonna throw the weather/sun off, no?
You can come up with new timekeeping systems when you need them. It's not like we can't convert between them.
~86,460 seconds in a day instead of 86,400.
Then two years later, the sun will be at its peak at midnight.
I guess thats true, but in the Stone age they can just deal with that lol
oh i know the answer. Since a mars day is about 15 minutes longer and out rover there are solar powered it was important that the human operators of them knew what time it was on mars. Nasa's answer, make a watch that runs about 2% slower. that git the mars watch an extra 15 minutes and so it syncs to the martian sun.
Figured there would be an answer like this, thanks!
you just have the ship day be the same length as an earth day and start count from day 0. So the ship launches and it clock starts ticking. Now you do need to ask is this going fast enough that time dilation is a thing? That will change how well it can ever sync up to earth.