An attosecond (as) is a very short period of time.[1] It is equal to one quintillionth of a second (or 0.000000000000000001 seconds). It can also be written as 10−18 seconds. Because it can be hard to think about how short this period of time is, on this page is a list of descriptions of periods of time longer than 1 attosecond, but shorter than one femtosecond (which is 10−15 seconds). This should help when thinking about periods of time that have different orders of magnitude.

  • 1 attosecond: It takes 1 attosecond for light to travel the length of three hydrogen atoms.
  • 1 attosecond: It takes 1 attosecond for an atomic nucleus to react when another particle hits it.
  • 150 attoseconds: It takes 150 attoseconds for an electron to circle the nucleus of an atom.
  • 320 attoseconds: It takes about 300 attoseconds for an electron to jump from one atom to another.

Related pages


  1. Website of the BIPM (Bureau International des Poids et Mesures) Archived 14 October 2011 at WebCite