A yoctometre is an SI

International System of Units

The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...

 measure of length that is equal to 10^-24 (yocto

Yocto

Yocto- is a prefix in the metric system denoting a factor of 10−24 or .Adopted in 1991 by the General Conference on Weights and Measures, it comes from the Greek οκτώ, meaning "eight", because it is equal to 1000−8. , yocto is the smallest confirmed SI prefix.It can be used to state a subatomic...

) of a metre

Metre

The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...

. A yoctometer is equivalent to 1/100 of the diameter of an electron

Electron

The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

, and 1/100 000 the diameter of a proton

Proton

The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....

 or neutron

Neutron

The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...

.

• 1 ym = 1 × 10^-24 metre
  Metre
  The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
  
  

In terms of relative length of units, a yoctometre ranks as follows: Planck length << yoctometre << zeptometre. A yoctometre is 1/1000 of a zeptometre (1 zeptometre (zm) = 1,000 yoctometres).

See also

1 E-24 m SI Si Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system... SI prefix SI prefix The International System of Units specifies a set of unit prefixes known as SI prefixes or metric prefixes. An SI prefix is a name that precedes a basic unit of measure to indicate a decadic multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol...

Orders of magnitude Orders of magnitude (length) octo