In reality, when we observe a length, say, 1 m.
But actually what does 1 m mean. If we magnify such 1 m x2. Will we still observe 1 m?
And what if there is no any other comparative objects, how can we know it is still 1 m? How can we know it is NOT sth else?
Regardless such philosophical meditation, there always is error in measurement, so we will put "error" or something called "uncertainty"to let us know how much this approximation will be:
1 m ± 0.001 m.
Then seemingly the problem is solved.
Not really,
what we've done is making an expected result of calculation.
But how exactly long such a " 1 m ± 0.001 m " is ?
Ok let's magnify such "1 m" X 100000000000000
so that we can even clearly observe such a "1 m"
What can I see? Let's see.
I see a plenty of atoms??
And there is empty space.....??
And based on quantum physics...... how can I accurately measure the position and the momentum of an atom at the same time???
And what can I know how exactly long can "these" empty space can be?? Does it have length?? If it has, is space an object?? How can I compare space to sth else ..... and WHAT is the "sth else" ??
Damn!! How long is 1 m?
Then, to my knowledge, " 1 m" becomes sth I can't be certain about....
P.S. actually "1 m" is defined as how long light will travel during certain time.
"If we magnify such 1m x2, will we still observe 1m?
Yes, the subject is 1m. But the measurements may be a bit different. No matter what, measure twice often give you different results.
You got it, 1m is by comparison, indeed, all scientific measurements with proper unit are by comparison!!
Since we understand measurement error is unavoidable, so 1m ± 0.001m is just some expression tool for usage.
Anyway it is useful, good enough, for example to build a house for you.
When you magnify such "1m" X 100000000000000, you see atom and/or space, don't be confused.
Actually you magnified a metal rod (let's say) which is atom/space by nature.
The rod is NOT a true 1m, it never will be.... so, still no valid complaint yet.
Right, when you look into small enough (near the planck scale), "not sure about empty space? length? object? else?"
Who cares about the exact single answer? Even god does not care about it!
God is an auditor in this case, he cares only about checksum, statistics.
In this way, you cannot cheat god anything in any daily scale!
Finally, you know "1m is defined as how long light will travel during certain time."
Traslated: Light travels the distance in 9,192,631,770 / 299,792,458 (some kind of "standard") cycle of caesium133 atom, which is a scaled ratio of c (speed of light) in nature. (THE ANSWER.)"
an response from the internet by Pseudo
