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Comment by saulpw

1 day ago

There are 3 orders of magnitude between nano (^-9) and pico (^-12). An Angstrom is ^-10m.

Useless fact I just learned from Wikipedia: Ångström/Angstrom (in Sweden of course we still use the original spelling) has its own UNICODE symbol, Angstrom sign: Å (U+212B) not to confuse with the Swedish letter Å (U+00C5). Looks slightly different in my browser.

https://en.wikipedia.org/wiki/Angstrom

  • Looks like that's deprecated. From the next sentence:

    However, version 5 of the standard already deprecates that code point and has it normalized into the code for the Swedish letter U+00C5 Å `latin capital letter a with ring above`

Aaahhh, ok, thanks!

  • You had the right idea. Angstroms are not an SI unit. The SI units jump by three orders of magnitude at this scale: picometer, nanometer, micrometer, millimeter.

    (In the same way that meter jumps three orders of magnitude to kilometer[1], or millions to billions to trillions, etc.)

    [1] Technically there are intermediate SI units between meter and km but nobody uses them. There are not intermediate SI units between the tiny ones.

    • Why above 1mm do we go by tens instead of thousands?

      We have centimeter (10 mm) then decimeter (100mm) then meter (1000mm). Then we jump to thousand again (kilometer).

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