Gravitation · Interactive

Gravity & g-Variation

Slide a test mass from a planet's core out into deep space and watch its weight change. Gravity climbs straight up from zero at the centre, peaks exactly at the surface, then thins out as the inverse square of distance beyond.

● Planet cross-section ● Test mass at r g rises linearly inside · falls as 1/r² outside

Setup

Distance from centre r 1.00 R
Surface gravity g_s 9.8 m/s²
Test mass m 10 kg
g = 9.80 m/s²
Local gravity at r
9.80
g (m/s²)
98.0
weight (N)
surface
region
1.00
r / R
inside g = g_s·r/R outside g = g_s·(R/r)² depth g = g_s(1−d/R) height g = g_s/(1+h/R)²

Playback

Try this: g peaks exactly at the surface (r = R). Halve r while inside and g halves; double r while outside and g drops to a quarter. Weight follows g precisely — mass never changes.