Anaximenes was from Miletus (a Greek city-state in Ionia), and was a pupil of Anaximander. Anaximenes proposed that the single common element making up all things in the universe was limitless air always in motion. Things come into or pass out of being because of heat or cold. When air is condensed and contracted it is cold, and when air is rarefied it is hot. He thought that when air is uniform it is transparent but heat, the cold, and motion make the air visible. Air becomes fire, itself, wind, cloud, water, Earth, and stone when rarefied or condensed in that order. These variations of air explain: the wind, which he thinks is moving condensed air; clouds, which are air condensed further than wind; rain, i.e. water, which is air condensed further than a cloud; snow, is air condensed more than rain; hail is air condensed more than snow. He had the same speculation as Anaximander on the cause of lightning, to wit, that it is caused by wind breaking a cloud apart. He thought that rainbows are created when the suns rays fall on compacted air, and he thought that earthquakes are caused by intense heating or cooling of the Earth. He believed that the sun, the moon, and the stars are all flat discs of fire that can ride the air because of their flatness (because he had observed that thin, flat objects have air resistance and appear to float) and were all created by a mist that was evaporated from the Earth. The Earth is also a thin, flat disc that can just rest on the air because of its shape. And oddly enough he believed that the sun, moon, and stars do not go under the Earth but around it along a similar plane as the ground, and the sun cannot be seen at night because it is so far away or is blocked by higher parts of the Earth.