Geocentric model explanation in terms of the Earth's revolution about the sun. In 1838, astronomer Friedrich Wilhelm Bessel measured the parallax of the star 61 Cygni successfully, and disproved Ptolemy's claim that parallax motion did not exist. This finally confirmed the assumptions made by Copernicus, providing accurate, dependable scientific observations, and conclusively displaying how distant stars are from Earth. A geocentric frame is useful for many everyday activities and most laboratory experiments, but is a less appropriate choice for solar system mechanics and space travel. While a heliocentric frame is most useful in those cases, galactic and extragalactic astronomy is easier if
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