Convert Astronomical Unit (AU) to Angstrom (Å) instantly.
About these units
Astronomical Unit (AU)
The astronomical unit (AU) is one of the most important distance units in astronomy and planetary science. Defined as exactly 149,597,870,700 meters, it represents the average distance between Earth and the Sun. Early astronomers could estimate the AU only indirectly through geometric and observational methods; modern techniques such as radar ranging and spacecraft telemetry have vastly improved its precision. The AU serves as a natural and intuitive scale for describing distances within the solar system. Planetary orbits, asteroid trajectories, comet paths, and interplanetary mission distances are often expressed in astronomical units because they avoid cumbersome scientific notation. For instance, Jupiter orbits at about 5.2 AU from the Sun, while the asteroid belt lies roughly between 2 and 3.3 AU. Beyond practical measurement, the AU forms part of a conceptual framework for understanding solar system layout. It appears in discussions of habitable zones, solar radiation intensity, and celestial mechanics. The unit's significance extends from education to high-level astrophysics, making it one of astronomy's cornerstone measurements.
Angstrom (Å)
The ångström, equal to 10⁻¹⁰ meters, is traditionally used to measure atomic scales, bond lengths, and wavelengths of electromagnetic radiation, particularly in the X-ray and ultraviolet regions. Although not an SI unit, the ångström persists because it aligns conveniently with many natural atomic dimensions — hydrogen's typical bond lengths, for example, are close to 1 Å. Scientists in crystallography, astronomy, materials science, and spectroscopy routinely use ångströms when describing the spacing between atoms in a crystal lattice or the wavelength of certain spectral lines. The convenience comes from avoiding unwieldy decimals: instead of writing 0.154 nm, one may write 1.54 Å. While modern research increasingly prefers SI nanometers or picometers, the ångström remains deeply embedded in scientific traditions and continues to serve as a practical shorthand for atomic-scale measurements.