Inferior and superior planets the orbit of Earth. These terms were originally used in the geocentric cosmology of Claudius Ptolemy to differentiate as inferior those planets (Mercury and Venus) whose epicycle remained co-linear with the Earth and Sun, and as superior those planets (Mars, Jupiter, and Saturn) that did not. In the 16th century, the terms were modified by Copernicus, who rejected Ptolemy's geocentric model, to distinguish a planet's orbit's size in relation to the Earth's. When Earth is stated or assumed to be the reference point: The terms are sometimes used more generally; for example, Earth is an inferior planet relative to Mars.
Earth in the Balance to react in time to save our skins”. Earth in the Balance Earth in the Balance: Ecology and the Human Spirit (, paperback ) is a 1992 book written by Al Gore, published in June 1992, shortly before he was elected Vice President in the 1992 presidential election. Known by the short title "Earth in the Balance", the book explains the world's ecological predicament and describes a range of policies to deal with the most pressing problems. It includes a proposed "Global Marshall Plan" to address current ecological issues. Written while his son was recovering from a serious accident, "Earth