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HISTORY OF SCIENCE AND TECHNOLOGY
Jupiter's Great Red Spot
The first recorded observation of Jupiter's Great Red Spot was by Robert Hooke in 1665. Giovanni Cassini referred to it as the "Eye of Jupiter" when he saw it through his telescope in 1666. Between 1666 and 1708 the Red Spot seems to have vanished at least eight times. William Dawes, famous for his drawings of Mars, observed it in 1857, and by 1883 it had faded until it was almost invisible. Then, in 1878, it became a vivid red colour and that is when it was given its name. Since 1878 it has faded until its present tan colour.
Photo taken from Voyager 1 in 1979 © NASA
The Great red Spot also varies in size. It is presently around 24000 km long but has been up to 48000 km in length. It reached this maximum size at the end of the 19th century. Even at its present size, two Earths could fit comfortably inside it.
Scientists believe that the Great Red Spot is a long-lasting storm. It is a tremendous hurricane made up of groups of thunderstorms. Its temperature is slightly lower than the surrounding gases and this indicates that the Great Red Spot is higher in the atmosphere. It is a high pressure system, spinning counter-clockwise.
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