yocto-
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yocto- (symbol y) is an SI prefix in the SI system of units denoting a factor of 10−24 or 0.000000000000000000000001.
Adopted in 1991, it comes from the Greek οκτώ, meaning eight, because it is equal to 1/10008. As of 2007, yocto- is the smallest SI prefix to be confirmed.
It can be used for measuring a subatomic particle's mass, for example:
1000m | 10n | Prefix | Symbol | Since[1] | Short scale | Long scale | Decimal |
---|---|---|---|---|---|---|---|
10008 | 1024 | yotta- | Y | 1991 | Septillion | Quadrillion | 1 000 000 000 000 000 000 000 000 |
10007 | 1021 | zetta- | Z | 1991 | Sextillion | Trilliard | 1 000 000 000 000 000 000 000 |
10006 | 1018 | exa- | E | 1975 | Quintillion | Trillion | 1 000 000 000 000 000 000 |
10005 | 1015 | peta- | P | 1975 | Quadrillion | Billiard | 1 000 000 000 000 000 |
10004 | 1012 | tera- | T | 1960 | Trillion | Billion | 1 000 000 000 000 |
10003 | 109 | giga- | G | 1960 | Billion | Milliard | 1 000 000 000 |
10002 | 106 | mega- | M | 1960 | Million | 1 000 000 | |
10001 | 103 | kilo- | k | 1795 | Thousand | 1 000 | |
10002/3 | 102 | hecto- | h | 1795 | Hundred | 100 | |
10001/3 | 101 | deca- | da | 1795 | Ten | 10 | |
10000 | 100 | (none) | (none) | NA | One | 1 | |
1000−1/3 | 10−1 | deci- | d | 1795 | Tenth | 0.1 | |
1000−2/3 | 10−2 | centi- | c | 1795 | Hundredth | 0.01 | |
1000−1 | 10−3 | milli- | m | 1795 | Thousandth | 0.001 | |
1000−2 | 10−6 | micro- | µ | 1960[2] | Millionth | 0.000 001 | |
1000−3 | 10−9 | nano- | n | 1960 | Billionth | Milliardth | 0.000 000 001 |
1000−4 | 10−12 | pico- | p | 1960 | Trillionth | Billionth | 0.000 000 000 001 |
1000−5 | 10−15 | femto- | f | 1964 | Quadrillionth | Billiardth | 0.000 000 000 000 001 |
1000−6 | 10−18 | atto- | a | 1964 | Quintillionth | Trillionth | 0.000 000 000 000 000 001 |
1000−7 | 10−21 | zepto- | z | 1991 | Sextillionth | Trilliardth | 0.000 000 000 000 000 000 001 |
1000−8 | 10−24 | yocto- | y | 1991 | Septillionth | Quadrillionth | 0.000 000 000 000 000 000 000 001 |