Tidal force
Tidal force is caused by gravity and makes tides happen. This is because the gravitational field changes across the middle of a body (the diameter).
Tidal Force Media
Tidal interaction between the barred spiral galaxy NGC 169 and a smaller companion
Figure 4: The Moon's gravity residual field at the surface of the Earth is known (along with another and weaker differential effect due to the Sun) as the tide generating force. This is the primary mechanism driving tidal action, explaining two simultaneous tidal bulges; Earth's rotation accounts further for the occurrence of two high tides per day on the same location.
Figure 3: Graph showing how gravitational attraction drops off with increasing distance from a body
Figure 5: Saturn's rings are inside the orbits of its principal moons. Tidal forces oppose gravitational coalescence of the material in the rings to form moons.
Figure 2: This simulation shows a star getting torn apart by the gravitational tides of a supermassive black hole.
Figure 6: Tidal force is responsible for the merge of galactic pair MRK 1034.
Figure 7: Graphic of tidal forces. The top picture shows the gravity field of a body to the right (not shown); the lower shows their residual gravity once the field at the centre of the sphere is subtracted; this is the tidal force.
