Geocentric model the coordinate system in order to predict the motions of planetary bodies, though doing so may make calculations easier to perform or interpret. A geocentric coordinate system can be more convenient when dealing only with bodies mostly influenced by the gravity of the Earth (such as artificial satellites and the Moon), or when calculating what the sky will look like when viewed from Earth (as opposed to an imaginary observer looking down on the entire solar system, where a different coordinate system might be more convenient). The Ptolemaic model of the solar system held sway into the early modern age;
Overkill (term) Overkill (term) Overkill is the use of excessive force or action that goes further than what is necessary to achieve its goal. It implies that, while the goal was accomplished, there was collateral damage as a result. It may be a literal term referring to physical damage, though it is also used in colloquial conversation as a metaphor. An example is killing an ant with a sledgehammer. "Overkill" is especially used to refer to a destructive nuclear capacity exceeding the amount needed to destroy an enemy. The term is attested from 1946 and was in common use during the Cold