So many well-fed cats have achieved fame in today’s world of social media that it is difficult to imagine a time when the funny behavior of cats went largely unrecorded. Fortunately, creative types have long seemed to enjoy their company and some past literary greats were only too happy to put pen to paper in celebration of their favourite cats.

Dr Samuel Johnson, is best remembered today for compiling (编纂) the first modern English Dictionary. The entry for cats is hardly flattering: “A domestic animal that catches mice, commonly considered by naturalists the lowest order of the lionlike species.” Yet, Johnson is known to have been devoted to his own pets, particularly Hodge, whom he once famously described as “a very fine cat indeed”.

During the Bronte sisters’ childhood, the three famous 19th-century novelists enjoyed the company of a black cat, named Tom. Charlotte included a description of a pet in Jane Eyre, while Emily wrote an essay in French in praise of cats entitled Le Chat. The title character of Anne’s first novel, Agnes Grey, decides her future husband is the man for her when he rescues a cat.

Edgar Allan Poe’s story, The Black Cat, is so vivid in its description of animal cruelty that it is difficult to imagine its author as an animal lover. Yet, in real life Allan and his cat Catterina were so obviously devoted to each other that, in 1849, they passed away at the exact same moment even though they were many miles apart.

Cats appear in some of the US humorist and novelist’s best-known works such as The Adventures of Tom Sawyer. Twain’s favourite cat was Bambino, whom he taught to switch off the lamp at night and took great delight in having it show off this party trick when visitors came to the house.

In the early 1940s, Hemingway moved to Cuba. Boise became the author’s constant companion. Hemingway later featured a cat of the same name in his novel, Islands in the Stream, which shared many characteristics of his real-life cat including a fondness for hunting fruit rats.

Satellites are an important part of our ordinary lives. For example, the information for weather forecasts is sent by satellite. Some satellites have cameras which take photographs of the Earth to show how clouds are moving. Satellites are also used to connect our international phone calls.

Computer connections of the World Wide Web and Internet also use satellites. Many of our TV programmes come to us through satellite. Airplane pilots sometimes also use a satellite to help them find their exact location.

We use satellites to send television pictures from one part of the world to another. They are usually 35,880 kilometres above the equator (赤道). Sometimes we can see a satellite in the sky and it seems to stay in the same place. This is because it is moving around the world at 11,000 kilometres an hour — exactly the same speed that the earth rotates (转动). A satellite must orbit the Earth with its antennae (天线) facing the earth. Sometimes, it moves away from its orbit, so there are little rockets on it which are used to put the satellite back in the right position. This usually happens about every five or six days.

Space is not empty! Every week, more and more satellites are sent into space to orbit the Earth. A satellite usually works for about 10-12 years. Satellites which are broken are sometimes repaired by astronauts or sometimes brought back to the Earth to be repaired. Often, very old or broken satellites are left in space to orbit the Earth for a very long time. This is very serious because some satellites use nuclear power and they can crash into each other.

The earliest discovered cave paintings date back to the Upper Paleolithic (旧石器) period. We might expect that they would be simply made, but the cave paintings of Spain and southern France show a high degree of skill. So do the cave paintings in southern Africa. Some of those appear to have been painted as much as 28,000 years ago, which suggests that painting in Africa is as old as painting in Europe. The early Australians may have painted on the walls of rock shelters at least 30,000 years ago.

The researchers identified three principal locations of paintings in the caves of western Europe: in obviously inhabited rock shelters and cave entrances; in galleries near the inhabited areas of caves; and in the inner reaches of caves, whose difficulty of access has been interpreted as a sign that magical-religious activities were performed there.

The subjects of the paintings are mostly animals. The paintings rest on bare walls, with no decoration. Perhaps, like many contemporary peoples, Upper Paleolithic men believed that the drawing of a human image could cause death or injury, and if that were their belief, it might explain why human figures are rarely found in cave art. Another explanation for the focus on animals might be that these people sought to improve their luck at hunting.

The particular symbolic significance of the cave paintings in southwestern France is more clearly revealed by the results of a study. The data suggest that the animals in the cave paintings were mostly the ones that the painters preferred for meat. For example, wild cattle and horses are found more often than we would expect by chance, probably because they were larger and heavier (meatier) than other animals in the environment. In addition, the paintings mostly draw animals that the painters may have feared the most because of their size, speed, natural weapons such as horns. That is, mammoths (猛犸) are drawn more often than deer.