Attosecond

An attosecond is an SI unit of time equal to 10⁻¹⁸ of a second (one quintillionth of a second).^[1] For context, an attosecond is to a second what a second is to about 31.7 billion years.^[2][3]

The word "attosecond" is formed by the prefix atto and the unit second. Atto- was made from the Danish word for eighteen (atten).^[4] Its symbol is as.

An attosecond is equal to 1000 zeptoseconds, or ¹⁄₁₀₀₀ of a femtosecond. Because the next higher SI unit for time is the femtosecond (10⁻¹⁵ seconds), durations of 10⁻¹⁷ s and 10⁻¹⁶ s will typically be expressed as tens or hundreds of attoseconds:

• (Shorter time: zeptosecond)

Times which can be expressed in attoseconds:

• 1 attosecond: the time it takes for light to travel the length of three hydrogen atoms
• 12 attoseconds: record for shortest time interval measured as of 12 May 2010^[5]
• 24 attoseconds: the atomic unit of time
• 67 attoseconds: the shortest pulses of laser light yet created^[6]
• 100 attoseconds: fastest ever view of molecular motion^[7]
• 200 attoseconds (approximately): half-life of beryllium-8, maximum time available for the triple-alpha process for the synthesis of carbon and heavier elements in stars
• 320 attoseconds: estimated time it takes electrons to transfer between atoms^[8]

• (Longer time: femtosecond)

See also

• Attophysics
• Flash (comics)

References