|(unit, humour)||attoparsec - About 31 mm (one inch). "atto-" is the
standard SI prefix for multiplication by 10^-18. A parsec
(parallax-second) is 3.26 light-years; an attoparsec is thus
3.26 * 10^-18 light years. Thus, one attoparsec per
microfortnight is about one inch per second.|
This unit is reported to be in use (though probably not very seriously) among hackers in the UK.