Convert length and distance units — meters, feet, inches, kilometers, miles, light years and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 μm | 6.684e-21 au | |
| 0.01 μm | 6.684e-20 au | |
| 0.1 μm | 6.684e-19 au | |
| 1 μm | 6.684e-18 au | |
| 5 μm | 3.342e-17 au | |
| 10 μm | 6.684e-17 au | |
| 50 μm | 3.342e-16 au | |
| 100 μm | 6.684e-16 au | |
| 1000 μm | 6.684e-15 au |
Multiply the number of Micrometers by 6.6845×10-18 to get Astronomical Units. Formula: au = μm × 6.6845×10-18. Example: 10 μm × 6.6845×10-18 = 6.6845×10-17 au. To reverse, divide Astronomical Units by 6.6845×10-18 to get Micrometers.
| Micrometer (μm) | Astronomical Unit (au) |
|---|---|
| 0.001 μm | 6.6845×10-21 au |
| 0.01 μm | 6.6845×10-20 au |
| 0.1 μm | 6.6845×10-19 au |
| 0.5 μm | 3.3422×10-18 au |
| 1 μm | 6.6845×10-18 au |
| 2 μm | 1.3369×10-17 au |
| 5 μm | 3.3422×10-17 au |
| 10 μm | 6.6845×10-17 au |
| 20 μm | 1.3369×10-16 au |
| 50 μm | 3.3422×10-16 au |
| 100 μm | 6.6845×10-16 au |
| 250 μm | 1.6711×10-15 au |
| 500 μm | 3.3422×10-15 au |
| 1000 μm | 6.6845×10-15 au |
| 10000 μm | 6.6845×10-14 au |
To convert Micrometer to Astronomical Unit, multiply by 6.6845×10-18. Example: 10 μm = 6.6845×10-17 au
To convert Astronomical Unit back to Micrometer, divide by 6.6845×10-18 (multiply by 1.496×1017). Use the swap button above.
Start with 100 Micrometers = 6.6845×10-16 au as your reference point. Scale up or down from there.
Infrared telescope detectors have pixel sizes of 10–30 μm while observational targets use AU distances. Astronomers convert between μm detector geometry and AU source distances when calculating angular resolution and image scale.
Interplanetary dust particles collected by aircraft and spacecraft are 1–100 μm in size while their collection orbits and interplanetary trajectories use AU. Dust researchers convert between μm grain size and AU orbital position in every dust collection paper.
Coronagraph occulter discs are specified in micrometres for precision manufacturing while the solar corona they reveal extends to several AU — instrument engineers bridge both scales in coronagraph design specifications.
1 AU = 1.496×10¹⁷ μm — 150 quadrillion micrometres. Physics educators use μm-to-AU to make the Earth-Sun distance tangible: "The distance to the Sun expressed in micrometres is a 18-digit number — each micrometre the width of a human cell."
Dust grain growth in protoplanetary disks is tracked in micrometres while disk dimensions use AU. Disk evolution models convert between μm grain physics and AU-scale disk structure in every planet formation simulation.
Solar wind and interplanetary dust detectors on spacecraft measure particle sizes in micrometres while reporting their position in the solar system in AU — space physics papers contain both scales throughout.
The Micrometer is a unit of Length measurement (symbol: μm). 1 μm = 6.6845×10-18 au. Used in scientific and practical Length measurement applications.
The Astronomical Unit is a unit of Length measurement (symbol: au). It is part of an internationally recognised measurement system used alongside the Micrometer.
The micrometre (micron) was formally named in 1879 by the International Committee for Weights and Measures — the prefix 'micro' from the Greek 'mikros' (small) combined with 'metre'. The unit predates its name: the micrometer screw gauge was invented by William Gascoigne, an English astronomer, around 1638, and a refined version was described by Adrien Auzout and Robert Hooke in the 1660s. Jean-Louis Palmer in Paris developed the modern micrometer calliper in the 1840s, making precision measurement to one-thousandth of a millimetre routinely achievable. Today the micrometre is the primary unit of precision in mechanical engineering, biology, and environmental science — defining the boundary between the visible world and the molecular world.
The astronomical unit has ancient roots — Aristarchus of Samos attempted to measure the Earth-Sun distance around 270 BC. For centuries the AU was estimated using Venus transit observations. Edmond Halley organised the first coordinated international transit-of-Venus expedition in 1716. The modern value was determined by radar ranging to Venus in 1961. The IAU formally defined the AU as exactly 149,597,870,700 metres in 2012.
Common use: Micrometer to Astronomical Unit conversion is needed when working with international standards, scientific publications, or reference materials that use different unit systems for Length measurement.