Convert length and distance units — meters, feet, inches, kilometers, miles, light years and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 Å | 6.684e-25 au | |
| 0.01 Å | 6.684e-24 au | |
| 0.1 Å | 6.684e-23 au | |
| 1 Å | 6.684e-22 au | |
| 5 Å | 3.342e-21 au | |
| 10 Å | 6.684e-21 au | |
| 50 Å | 3.342e-20 au | |
| 100 Å | 6.684e-20 au | |
| 1000 Å | 6.684e-19 au |
Multiply the number of angstroms by 6.68459×10⁻²² to get astronomical units. Formula: au = Å × 6.68459×10⁻²². For example, 1,000 Å × 6.68459×10⁻²² = 6.685×10⁻¹⁹ au. To reverse, divide astronomical units by 6.68459×10⁻²² (or multiply by 1.496×10²¹).
| Angstroms (Å) | Astronomical Units (au) | Context |
|---|---|---|
| 0.1 Å | 6.685×10⁻²³ au | Smallest atomic bond (H–H: 0.74 Å) |
| 0.53 Å | 3.542×10⁻²² au | Hydrogen Bohr radius |
| 1 Å | 6.685×10⁻²² au | 1 ångström — named unit baseline |
| 1.54 Å | 1.029×10⁻²¹ au | C–C bond length / Cu Kα X-ray |
| 2 Å | 1.337×10⁻²¹ au | Typical covalent bond range |
| 3.52 Å | 2.353×10⁻²¹ au | Diamond lattice parameter |
| 10 Å | 6.685×10⁻²¹ au | 1 nanometer = 10 Å |
| 100 Å | 6.685×10⁻²⁰ au | Small protein molecule diameter |
| 400 Å | 2.674×10⁻¹⁹ au | Violet light wavelength (40 nm) |
| 5,500 Å | 3.676×10⁻¹⁸ au | Green light — peak human vision |
| 7,000 Å | 4.679×10⁻¹⁸ au | Red light wavelength limit |
| 10,000 Å | 6.685×10⁻¹⁸ au | 1 micron (μm) = 10,000 Å |
| 1,000,000 Å | 6.685×10⁻¹⁶ au | 0.1 mm — visible to naked eye |
The simplest conversion to remember. Since nanometers are more commonly used today, multiply angstroms by 0.1 to get nanometers. 5,500 Å = 550 nm (green light).
One astronomical unit (Earth–Sun distance) is about 150 billion meters. That's why converting angstroms to AU always produces astronomically small numbers like 10⁻²².
The entire visible spectrum fits in a 3,000 Å window. Violet starts at ~4,000 Å, green peaks at ~5,500 Å, red ends at ~7,000 Å. UV is below 4,000 Å, infrared above 7,000 Å.
Each step is a factor of 10 (nm), 1,000 (μm), 10 million (mm), 10 billion (m), 10 trillion (km), then ~150 trillion km = 1 AU. The angstrom is 32 orders of magnitude below 1 AU.
Scientists studying stellar spectra work in angstroms for wavelength data, then convert to astronomical distances to model how light travels across solar systems.
Emission and absorption lines in stellar spectra are measured in angstroms. Astronomers correlate these atomic-scale wavelengths with objects millions of AU away.
Students converting between atomic-scale units and astronomical units to understand the extreme range of length scales in the universe — from subatomic to galactic.
Crystal structures measured in angstroms are compared against X-ray wavelengths and source distances in AU when calibrating synchrotron beamlines.
Computational physicists need consistent units across atomic and cosmic scales in simulations of phenomena like solar wind interacting with planetary magnetospheres.
Papers bridging atomic physics and astronomy require precise unit conversions to present data in the most relevant scale for the audience and context.
The angstrom equals 10⁻¹⁰ meters (0.1 nanometers). Named after Swedish physicist Anders Jonas Ångström (1814–1874), who pioneered spectroscopy. Though not an SI unit, it remains the standard in crystallography, atomic physics, and optical spectroscopy because atomic bond lengths and light wavelengths fall naturally in the 1–10 Å range.
The astronomical unit equals approximately 1.496×10¹¹ meters — the mean distance from Earth to the Sun. Defined exactly as 149,597,870,700 meters by the IAU in 2012. Used as the standard ruler for distances within solar systems. Light takes about 8 minutes 20 seconds to travel 1 AU.
Anders Ångström mapped the solar spectrum in 1868 using a unit of 10⁻¹⁰ meters to express wavelengths, which became known as the angstrom in his honor. The astronomical unit has roots in early estimates of the Earth–Sun distance, formally defined in 2012 as a fixed constant. These two units represent opposite extremes of the length scale — one born from atomic physics, one from planetary astronomy.
Common use: Angstroms are used in atomic physics, crystallography, and spectroscopy. Astronomical units are used in planetary science and solar system astronomy. Converting between them appears in astrophysics research bridging quantum and cosmic scales.