Megameter is 1000000 meter units.
Megameters to Astronomical units Converter — Mm to AU
Convert Megameter (Mm) to Astronomical unit (AU) using the exact conversion factor (1 megameter = 0.0000066846 astronomical unit). See the formula, worked examples, conversion table, history, and common uses.
Megameters to Astronomical units converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
An astronomical unit is the mean Earth-Sun distance.
Result = input x 1e+6 / 1.49597871e+11.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Megameters to Astronomical units
Megameter and Astronomical unit both measure length. Specifically: Megameter is 1000000 meter units, and an astronomical unit is the mean Earth-Sun distance.
Formula
astronomical units = megameters × 0.00000668458712227
This factor comes from each unit's defined relationship to the category's base unit: 1 megameter equals 1000000 base units, and 1 astronomical unit equals 149597870700 base units, so dividing one by the other gives the direct megameter-to-astronomical unit factor of 0.00000668458712227.
Simple example
1 Mm × 0.000006684587122 = 0.0000066846 AU
1 megameter = 0.0000066846 astronomical units.
Real-world example
10 Mm × 0.000006684587122 = 0.0000668459 AU
10 megameters = 0.0000668459 astronomical units.
Conversion table
| Megameter (Mm) | Astronomical unit (AU) |
|---|---|
| 1 Mm | 0.0000066846 AU |
| 5 Mm | 0.0000334229 AU |
| 10 Mm | 0.0000668459 AU |
| 21.0975 Mm | 0.0001410281 AU |
| 42.195 Mm | 0.0002820562 AU |
| 100 Mm | 0.0006684587 AU |
Reverse conversion: Astronomical unit to Megameter
0.0000066846 AU × 149597.8707 = 1.000001926 Mm
0.0000066846 astronomical units = 1.000001926 megameters.
megameters = astronomical units × 149597.8707
For a page dedicated to this direction, see Astronomical unit to Megameter.
Understanding the Megameter (Mm)
Megameter is 1000000 meter units.
Understanding the Astronomical unit
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Where it's used: Used internationally in astronomy for solar-system-scale distances.
Uses of the Astronomical unit today
- Measuring distances within the solar system (planetary orbits)
- Astronomical calculations and spacecraft navigation
- Popular science communication about the solar system
History of the Astronomical unit
The astronomical unit originated from 17th-19th century attempts to measure the Earth-Sun distance, refined over time using transits of Venus and later radar and spacecraft ranging.
In 2012, the International Astronomical Union fixed the AU at exactly 149,597,870,700 meters, replacing its earlier definition (tied to gravitational calculations) with a simple fixed distance, independent of the slightly-variable actual Earth-Sun distance.
Historical origin. Astronomical unit was not the invention of a single named person; it developed through the process described above.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many astronomical units are in 1 megameter?
1 megameter equals 0.0000066846 astronomical units, using the exact defined conversion factor rather than an estimate.
How do I convert megameter to astronomical unit?
Multiply the megameter value by 0.000006684587122. The converter above does this instantly to whatever precision you set.
How do I convert astronomical unit back to megameter?
Use the reverse factor: 1 astronomical unit equals 149,597.8707 megameters. You can also use the swap control in the converter above to flip the direction instantly.
What is a megameter?
Megameter (Mm) is a unit of length.
What is a astronomical unit?
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Is the megameter to astronomical unit conversion exact?
Yes. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.