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).
Learn More in these related articles: heliocentric system. a cosmological model in which the Sun is assumed to lie at or near a central point (e.g., of the solar system or of the universe) while the Earth and other bodies revolve around it. In the 5th century bc the Greek philosophers Philolaus and Hicetas speculated separately that the Earth was a sphere...