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
Amherst Central Business District Amherst Central Business District The Amherst Central Business District is a historic district encompassing the heart of downtown Amherst, Massachusetts. Centered on the northern section of the long town common, the area has been the civic and commercial heart of the town since the 18th century. The district was listed on the National Register of Historic Places in 1991, and slightly enlarged in 2011. Amherst was originally part of Hadley, settled in 1661, and was itself known to have colonial settlements by 1728. It was incorporated in 1768. Its earliest focal point of settlement was in what is now its