Megameter
A megameter (Mm) is a unit of length in the metric system, equal to 1 million meters (1 Mm = 10⁶ meters or 1,000 kilometers). Megameters are used to measure very large distances, typically on a global or planetary scale. For example, the Earth’s diameter is about 12.7 megameters. Although it’s a valid metric unit, the megameter is rarely used in everyday life or science, as kilometers or other astronomical units are more common for such distances.
Earth Polar Radius
The Earth's polar radius is the distance from the center of the Earth to the North or South Pole. It measures the Earth’s radius along its rotational axis.
Its value is approximately 6,356.8 kilometers (about 3,949.9 miles).
The Earth is an oblate spheroid, so the polar radius is slightly shorter than the equatorial radius due to the planet's flattening at the poles.
This measurement is crucial for geodesy, understanding Earth’s shape, and satellite navigation.
Key facts:
Polar radius ≈ 6,356.8 km
Smaller than equatorial radius by about 21.3 km
Important for precise Earth modeling and mapping
The difference between the polar and equatorial radius reflects the Earth’s rotation and its effect on the planet’s shape.
No conversions available for length.