Moon the correct values of about 60 and 0.273 respectively. Archimedes (287–212 BC) designed a planetarium that could calculate the motions of the Moon and other objects in the Solar System. During the Middle Ages, before the invention of the telescope, the Moon was increasingly recognised as a sphere, though many believed that it was "perfectly smooth". In 1609, Galileo Galilei drew one of the first telescopic drawings of the Moon in his book and noted that it was not smooth but had mountains and craters. Telescopic mapping of the Moon followed: later in the 17th century, the efforts of Giovanni
Craters of the Moon (geothermal site) in diameter. The most powerful fumarole observed at Craters of the Moon occurred December 1967. It had a heat output of 116 MW. Currently, only one of the craters has a mudpool. Here the gases (mainly HS) react with water to form sulphuric acid. This reacts with the rocks, turning it to clay. When there is water present, this forms the grey coloured mudpools “that bubble and burp as steam and gas escape through them”. Much of the ground at Craters of the Moon is warm or hot. This of course affects the vegetation. Only few species can survive. One