Convert Attometer to Nanometer

An attometer is a metric unit of length equal to one quintillionth of a meter (1×10⁻¹⁸ m). It is among the smallest length units in the SI system and is used almost exclusively in particle physics and theoretical work involving sub-nuclear dimensions.

The attometer was defined using the SI prefix atto- (from Danish atten, meaning eighteen), adopted by the Conférence Générale des Poids et Mesures (CGPM) in 1964 to denote one quintillionth (10⁻¹⁸).

Attometers appear in particle physics literature when describing distances comparable to or smaller than nuclear dimensions, including the range of weak nuclear interactions and theoretical Planck-scale ratios. They are rarely encountered outside specialised scientific work.

SI prefix atto- adopted in 1964; the attometer became the standard unit for sub-femtometer measurements in high-energy physics from the late 20th century onward.

A nanometer is a metric unit of length equal to one billionth of a meter (1×10⁻⁹ m). It is the standard unit for measuring atomic and molecular dimensions and is widely used in physics, chemistry, and electronics.

Defined using the SI prefix nano- (from Greek nanos, "dwarf") to denote one-billionth, adopted by the General Conference on Weights and Measures (CGPM) in 1960.

Nanometers are used to measure wavelengths of visible light (400–700 nm), semiconductor transistor sizes (currently 3–5 nm process nodes), DNA double helix width (2 nm), and atomic radii. The 2019 SI redefinition fixed the meter to the speed of light, making nanometer definitions exact to atomic precision.

SI prefix nano- adopted by the CGPM in 1960; nanometer became the standard unit for nanotechnology and optical wavelengths during the late 20th century.