4 ms·

No, the meter is defined (as c times a certain number of seconds).

• javajosh 5y ago
  No, the meter is defined in terms of c and the hyperfine transition frequency of Cs-133 is defined https://physics.nist.gov/cgi-bin/cuu/Value?nucs https://physics.nist.gov/cgi-bin/cuu/Value?nucs. If that link isn't good enough, you can check out the SI Mises en pratique on the subject: https://www.bipm.org/en/publications/mises-en-pratique https://www.bipm.org/en/publications/mises-en-pratique Edit: I'm totally this guy right now https://xkcd.com/386/ https://xkcd.com/386/
  • a1369209993 5y ago
    > the meter is defined in terms of c That is what I just said: the meter is defined in terms of c, not vice versa.
    • javajosh 5y ago
      I think you are confused. I suggest you read up on this stuff. It's really fascinating, but you're not using the words right. Cheers, and good night.