So as two objects are separated from each other, the force of gravitational attraction between them also decrease. if the separation distance between 2 objects is doubled (increased by a factor of 2), then the force of gravitational attraction is decreased by a factor of 4 (2 raised to the second power).
Hope this helps :)
Erosion - The process in which water, ice, wind, or gravity moves pieces of rock or soil
The focal length of the lens is the distance between the lens and the image sensor when the subject is in focus, usually stated in millimeters (e.g., 28 mm, 50 mm, or 100 mm). In the case of zoom lenses, both the minimum and maximum focal lengths are stated, for example 18–55 mm.
