Right? Didn’t they define the kilogram, make identical copies of the standard, sent them to different countries, then after years, reunited them and found they all diverged in mass?

And now they have made a perfect silicon sphere with the same mass as the standard kilogram, then counted all the atoms. So now we know the exact mass in silicon atoms of a kilo.

Let’s just define tagliatelle in light nanoseconds and be done with it.