The most common way to become infected with giardia is after swallowing contaminated water. Giardia parasites are found in lakes, ponds, rivers and streams worldwide, as well as in municipal water supplies, wells, cisterns, swimming pools, water parks and spas.
Andreas Cellarius's illustration of the Copernican system, from the Harmonia Macrocosmica (1708). Heliocentrism, or heliocentricism, is the astronomical model in which the Earth and planets revolve around the Sun at the center of the Solar System. The word comes from the Greek (á¼¥Î»Î¹Î¿Ï helios sun and ÎºÎ­Î½ÏÏÎ¿Î½ kentron center).
Geocentric model. The geocentric model of the cosmos is a paradigm which places the Earth at the center of the universe. Common in ancient Greece, it was believed by both Aristotle and Ptolemy.Most Greeks assumed that the Sun, Moon, stars, and planets orbit Earth.Similar ideas were held in ancient China.he geocentric model was gradually replaced by the heliocentric model of Copernicus and Galileo due to the simplicity and predictive accuracy of that newer model. In this model, a set of fifty-five concentric crystalline spheres were considered to hold the Sun, the planets, and the stars.