Observer gravitational acceleration — astro_observer

Calculates the effective gravitational acceleration experienced by an observer on the Earth's surface. This combines inward gravitational acceleration with outward centrifugal acceleration due to Earth's rotation.

Usage

astro_observer_gravity(latitude, height)

Arguments

latitude: The geographic latitude of the observer in degrees north of the equator (range: -90 to +90). By formula symmetry, only the absolute value of latitude matters.
height: The elevation above sea level in meters. Accuracy is best in the range 0 to 100,000 meters.

Value

The effective gravitational acceleration in meters per second squared (m/s²).

The returned value increases toward the Earth's poles and decreases toward the equator, consistent with the weight measured by a spring scale of a fixed mass moved to different latitudes and heights on Earth.

Details

This function implements the WGS 84 Ellipsoidal Gravity Formula, which accounts for the Earth's oblate spheroid shape and rotation.

Examples

# Calculate gravity at sea level in different locations
gravity_equator <- astro_observer_gravity(latitude = 0, height = 0)
gravity_pole <- astro_observer_gravity(latitude = 90, height = 0)
gravity_sydney <- astro_observer_gravity(latitude = -33.8688, height = 0)

# Gravity is stronger at the poles
cat(sprintf("Equator: %.6f m/s²\n", gravity_equator))
#> Equator: 9.780325 m/s²
cat(sprintf("Pole: %.6f m/s²\n", gravity_pole))
#> Pole: 9.832185 m/s²
cat(sprintf("Sydney: %.6f m/s²\n", gravity_sydney))
#> Sydney: 9.796383 m/s²