Table: Metric Prefixes


    
    10**xx    Prefix       Comment
    
    10**30 quetta Q 10**27 ronna R 10**24 yotta Y 10**21 zetta Z 10**18 exa E Exaflop computing was the state of the art circa 2022. See Sophia Chen, 2024, Nature magazine: "A day in the life of the world's fastest supercomputer". 0.01 exameters ≅ 1 light-year. 10**15 peta P Petaflop computing was the state of the art circa 2018. 10**12 tera T The world power use is about 18 Terawatts circa 2019 (see Wikipedia: Watt: Terawatt). 10**9 giga G A gigayear (Gyr) is a billion years. 10**6 mega M Who wants to be a meganaire? 10**3 kilo k 10**2 hecto h As far as I know only used, sort of, for hectare (ha): 1 ha = 100 x 100 = 10**4 m**2 = (1/100) km**2 10**1 deca da Used now for decameter asteroids. 10**0 The basic unit case: i.e., the NO prefix case 10**(-1) deci d Only commonly used for decibels. 10**(-2) centi c 10**(-3) milli m Never confuse mJ and MJ. 10**(-6) micro μ The Greek letter μ (mu). 10**(-9) nano n Nanotechnology is very hot circa 2013. 10**(-12) pico p 10**(-15) femto f Used for ultrashort pulse lasers (AKA femtosecond lasers). 10**(-18) atto a 10**(-21) zepto z 10**(-24) yocto y 10**(-27) ronto r 10**(-30) quecto q

    Note: Some of the metric prefixes are rarely used like atto. But as technology advances, one often finds them turning up in specialized fields: e.g., nanotechnology uses nano- because supposedly the devices are at the nanometer scale: actually they are often at the hundreds of nanometer scale, but that doesn't sound as grant-attractive.

      Rumor has it that groucho (10**33) and harpo (10**(-33)) will soon be added to the metric prefixes.

    See also Wikipedia: Metric prefix: List of SI prefixes.
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