The moons gravitational force at different points on the earth
Explanation:
The perstubation force of the sun on the moon at two places in its orbit . The blue arrows represent the direction and magnitude of the gravitational force on the Earth. Applying this to both the Earth's and the Moon's position does not disturb the positions relative to each other. When it is subtracted from the force on the Moon (black arrows), what is left is the perturbing force (red arrows) on the Moon relative to the Earth. Because the perturbing force is different in direction and magnitude on opposite sides of the orbit, it produces a change in the shape of the orbit.
In astronomy , perturbation is the complex motion of a massive body subject to forces other than the
