Earth's Equatorial Radius to Astronomical Unit Converter
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32 units available
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How to Convert Earth's Equatorial Radius to Astronomical Unit
To convert Earth radii to meters: multiply by 6,378,137.
R⊕(eq) = 6,378,137 m = 6,378.137 km. Earth's oblateness = (R_eq − R_pol)/R_eq ≈ 1/298.257.
For example, 1 Earth's Equatorial Radius (R⊕ (eq)) = 0.00004263521245 Astronomical Unit (AU).
Earth's Equatorial Radius to Astronomical Unit — Common Values
| Earth's Equatorial Radius (R⊕ (eq)) | Astronomical Unit (AU) |
|---|---|
| 0.1 | 0.000004263521245 |
| 0.5 | 0.00002131760623 |
| 1 | 0.00004263521245 |
| 2 | 0.00008527042491 |
| 5 | 0.0002131760623 |
| 10 | 0.0004263521245 |
| 25 | 0.001065880311 |
| 50 | 0.002131760623 |
| 100 | 0.004263521245 |
| 500 | 0.02131760623 |
| 1000 | 0.04263521245 |
About Earth's Equatorial Radius (R⊕ (eq))
Definition
The Earth's equatorial radius is the distance from Earth's center to the equator, approximately 6,378.137 km.
Mathematical Relationship
R⊕(eq) = 6,378,137 m = 6,378.137 km. Earth's oblateness = (R_eq − R_pol)/R_eq ≈ 1/298.257.
Conversion Formula
To convert Earth radii to meters: multiply by 6,378,137.
Practical Applications
GPS calculations, satellite orbit determination, map projections, and geophysical modeling.
Interesting Facts
Earth is not a perfect sphere — the equatorial radius is about 21 km (0.3%) larger than the polar radius due to rotational flattening.
Common Mistakes
Using the equatorial radius as if Earth were a sphere — for precision, you must account for the oblate spheroid shape.
Educational Tips
Earth's equatorial radius (6,378 km) vs. polar radius (6,357 km) shows the planet bulges at the equator due to spinning.
About Astronomical Unit (AU)
Definition
The astronomical unit is a unit of length approximating the mean Earth-Sun distance, defined as exactly 149,597,870,700 meters.
Mathematical Relationship
1 AU = 149,597,870,700 m ≈ 149.598 Gm ≈ 499 light-seconds ≈ 8.317 light-minutes.
Conversion Formula
To convert AU to km: multiply by 149,597,870.7. To convert AU to light-years: divide by 63,241.
Practical Applications
Spacecraft mission planning, expressing planetary orbit sizes, and solar system scale models.
Interesting Facts
Light takes about 8 minutes and 20 seconds to travel 1 AU. Mars is about 1.52 AU from the Sun, Jupiter about 5.2 AU.
Common Mistakes
Thinking the AU is the exact Earth-Sun distance — Earth's actual distance varies from ~147 to ~152 Gm over the year due to orbital eccentricity.
Educational Tips
AU makes the solar system manageable: Mercury ≈ 0.39 AU, Venus ≈ 0.72, Earth = 1, Mars ≈ 1.52, Jupiter ≈ 5.2, Saturn ≈ 9.5.