ABSTRACT
Jupiter is much the largest and most massive planet in the Solar System; its mass is greater than those of all the other planets combined. It has been suggested that it may have been responsible for preventing approaching comets invading the inner Solar System, and thereby protecting the Earth from bombardment. Jupiter is well placed for observation for several months in every year. Occultations of and by Jupiter involving other planets are rare. Since Jupiter is generally the brightest object in the sky apart from the Sun, the Moon and Venus, it must have been known since the dawn of human history. Jupiter has the shortest ‘day’ insofar as the principal planets are concerned. The Great Red Spot is undoubtedly the most famous feature on Jupiter. In 1923 and 1924 a classic series of papers by H. Jeffreys finally disposed of the idea that Jupiter is a miniature sun, giving off vast amounts of heat.
