Two forces applied to an object in opposite directions will be subtracted. ... If the net force is zero, no change will happen to the object's motion. If the forces are unbalanced, meaning there is some amount of net force, then the object will move in the direction of the force.
Alfred Wegener was the first to highlight the theory of plate tectonics in world, and later on gave various evidence for the formation of plates that the shaped the earth landmass, the evidence he gave seemed to be quiet in accordance with his field of study called as the law of Uniformitarianism as the processes that operate today have been active in the past with varying intensities.
Evidence in the form of Gig zaw fit of two continent i.e the African coast with that of the South American coast that perfectly matches and which he believes to be part of the same Gondwanaland and northern part was Pangaea supercontinent.
Furthermore, the evidence of glossopteris flora where tends to found along with the lands bordering the two landmasses and faunal evidence of Lemure that tended to run westward are deposited in seabeds as evidence to the separation of to continents.
Another evidence of the similar type of glacial tracts found in various continents of the world has seen to emerge as a result of the carbon dating of rocks of that time.
The plate tectonic theory only applies to the rocky planets which have landmass to that of the earth i.e the terrestrial planets and not to the gaseous giants that are composed of the metallic core and high density of helium and hydrogen gases.
Currently, earth and few planets are considered to have water or liquid components and these too in icy forms like Saturn have rings of ice, ice on craters of the moon, etc.
