Tides and planetary orbits are caused by the pull of gravity.
Effects of Mass and Distance on Gravitational Force
- The more massive an object, the greater it’s gravitational pull.
- The closer the distance between objects, the greater the gravitational pull
- The gravitational pull between the Sun and the planets and between Earth and its Moon cause distinct motions between and among these bodies
- The Sun’s gravitational attraction, along with the planet’s inertia (continual forward motion), keeps the planets moving in elliptical orbits (Earth’s orbit is slightly oval) and determines how fast they orbit.
- Planets nearer the Sun move/orbit faster than planets farther from the Sun because the gravitational attraction is greater.
- When a planet is farther from the Sun, the gravitational attraction between them decreases and the planet moves/orbits slower.
- Since the Moon is closer to Earth than the Sun (distance), the Moon has the greatest pulling effect on tides, the rise and fall of Earth’s waters.
- The Sun also pulls on Earth and can combine its force with the Moon causing even higher tides, spring tides
- Or can be a right angles, pulling against the Moon’s pull, causing very little tidal change, neap tides.
The force of gravity is influenced by both the mass and distance of objects.
Investigate the relationship between the
force of gravity, mass, and distance
How the force of gravity from the massive Sun affects the motion of celestial objects to move in elliptical orbits.
How the force of gravity from the Moon and Sun affects Earth's tides.
What is gravity?