Nanometer
A nanometer (nm) is a microscopic metric unit equal to one-billionth of a meter. It is used in science and technology to measure atoms, wavelengths of light, and semiconductor components. Nanometers help describe the invisible structures that make modern electronics work.
Because nanometers are so tiny, converting to micrometers or meters helps give context to scientific data—especially in materials research and optics.
Astronomical Unit
An astronomical unit (AU) is a standard space measurement based on the distance from the Earth to the Sun—about 149.6 million kilometers or 93 million miles. It helps describe solar system distances in practical numbers rather than extremely large values.
Astronomers use AU values to measure orbits of planets, asteroids, and comets relative to Earth.