The ninth planet of the solar system was discovered not long ago. It happened in 1930. Scientists had been hunting for the planet for a long time. They had calculated its probable position but there was no proof that the planet really existed. It was too far away for the telescopes of that time to find it. It’s worth mentioning that the first photos of the planet were taken by a very young researcher. He was only twenty-four and had no formal education in astronomy. However he was deeply involved in the search for the ninth planet. The planet at the edge of the solar system was called Pluto, after the Roman god. The name for the planet was suggested by an 11-year-old British girl.

Today it is hard to imagine Moscow being dark at night. Yet, the central streets of the city became bright only in 1730. Before then, Muscovites had to keep candles burning in the windows for passers-by. Most people also carried individual oil lamps when they walked late. During the summer months, candles and oil lamps were not allowed because of the risk of fire. Later, gas lanterns appeared. They were rather effective but the real progress started later, with electric lamps. 448 electric lamps were fixed in the centre of Moscow a century ago. At present, Moscow has a modern system of street lights with electronic control.

According to surveys, the popularity of bikes is growing. More than 700 cities in the world have joined a new program for cyclists. Any person can take a vacant bike and park it back at any bike station on their way. One can find information about the bike stations on smartphone maps. Cycling in cities helps to lessen the problems of stress and air pollution. Research held in London in 2017 confirmed this fact. People felt calmer after they rode to the office instead of driving. Also, bikes do not produce harmful gases.

Glass is a natural mineral. Natural glass is grey and hard to look through. Man-made glass was first produced in Egypt 5000 years ago. It was used for decorations because it had a green or blue colour. The secret of clear glass was found in Europe only in the 13th century. At the same time, craftsmen learned to produce lenses to look at small objects or to be used by people who had problems with their eyes. This is how the first glasses appeared. Glass dishes and mirrors became popular later with the rise of technology. In Russia, the first glass factory was built in Moscow region in 1654.

People have always wanted to learn and share information. At different times they I used different methods to exchange news. They made fires and beat drums to signal important events. Later, they invented letters which were carried by special people called runners. They had to cover long distances to deliver information. The use of horses and birds made the delivery quicker. The state post in Russia appeared in the 17th century. It was rather slow but quite reliable. In 1851, the post started to use the railway. Since then the speed of information exchange has been growing constantly.

Making weather forecasts is hard, complicated, scientific work. 70 per cent of its success depends on the accurate analysis of air pressure. Areas of pressure up to 9 kilometers above the Earth are measured by computers. Devices also record the vertical movement of air that can cause clouds, rain and snow. If the air goes down towards the Earth, it destroys the clouds and we can enjoy the blue sky. A front in the atmosphere is another important factor for predicting the weather. The fronts may stretch for thousands of kilometers and can be clearly seen from space. It's interesting that cold fronts move faster that warm ones.

Scientists have long been working on new orbital technologies for growing plants. They tried to grow different plants on the International Space Station. Then the plants were sent back to the Earth for further study. This year, for the first time, astronauts could eat green leaves grown in space. Space farming is extremely important for the future space missions planned to Mars because it gives fresh food and vitamins. The new plant growing system is very smart. It informs humans when the plants need water. Special sensors measure the thickness of the leaves. If they become too thin, detectors send signals. This technology helps save water in space and grow a good harvest.

Within the next hundred years or so, people will have to get energy from alternative sources. Alternative sources are also needed to put a stop to pollution. There are different alternative sources that are already successfully used in many countries. One example is the Dead Sea, which produces electricity. When the sun heats the surface of the lake, the hotter and heavier layers of salty water sink. At the same time, the colder and lighter layers rise. The hot water can be stored at the bottom of the lake or piped away. It can be used to heat many buildings or to generate electricity. It costs only a third as much as oil heating.

The first linguistic theories appeared around the 5th century B.C. in India, Greece, I Rome, and China. In order to understand texts better, the first linguists studied different aspects of the language, philosophy, and culture. Most early studies in I India were based on ancient songs. For the first time, ancient linguists distinguished words as nouns and verbs. This is how parts of speech appeared. Grammar and phonetics were later developed in Greece and Rome. Chinese linguists wrote t first dictionaries of synonyms. The first dictionary of the English language appeared much later, in 1755. It had 40,000 words.

In many European countries, recycling has become a part of government policy. Modern technologies make it possible to produce new packaging, bottles and even clothes from household waste. Germany has also recently started a series of projects to encourage people to sort the rubbish they throw away. There are special containers of different colours that are meant for plastic, glass, paper and food. Those people who ignore the rules can be fined by the 'rubbish police'. Official laws also regulate the standards for rubbish packing, transportation and storage. These complex measures help to create a healthy environment in towns and cities.

Cats and people have been living together for thousands of years. Nowadays, domestic cats are extremely popular pets. According to statistics, they are even more popular than dogs. There is no doubt that cats love people as much as people appreciate them. Maybe it's because cats and humans share some physiological traits. For instance, a cat's brain is more similar to a human brain than a dog's. The regions of the brain responsible for emotion are identical in both humans and cats. Cats also have A and B blood types, just like people.

Nowadays people prefer communicating online. However, 50 years ago people sent paper letters to each other. It was the norm to have a mail box full of envelopes with letters. The envelopes were used for keeping letters and documents. The first envelopes appeared in England in the first half of the 19th century. In Moscow, massive sales of envelopes started in 1846. The first envelopes were made of white paper. They were of a different format. To post a letter people needed round hand-made stamps. The stamps were fixed in the top right corner of the envelope. In St. Petersburg, stamps were blue, in Moscow they were red. Two years later, envelopes spread over the whole territory of Russia.

This fish is called the Black sea devil. We don't know much about it. It lives deep I in the darkness of the sea and seldom comes up. Scientists aren't even sure how I long it lives. The amazing fact is that the Black sea devil can perfectly adapt tt its environment. They have sharp teeth, a big mouth arid beautiful fins used for I swimming and hunting. Male fish live on the back of female ones that are much I bigger in size. Not long ago, a Black sea devil was filmed in its natural environment for the first I time. The fish was then brought to the surface alive for further monitoring. It was placed in a cool, dark container. Scientists want to know if it can sense magnetic fields like sharks do. A set of experiments will help to find out.

It's understood that the age of oil and gas is coming to an end. If we continue burning these supplies, we'll soon run out of them. Now everybody agrees that alternative energy technologies are our only prospect for the future. The solar, wind, and water technologies are successfully used nowadays. There are planes, cars, and boats that run without a drop of fuel. Solar Sailor was the first ferryboat in Australia with solar wings. Since 2000 it has been successfully used in Sydney. It holds up to 100 passengers on board and is still popular with residents and tourists. Nowadays ferries like Solar Sailor, which are absolutely eco-friendly, are widely used in many countries for sightseeing, sea parties, and carrying people and goods.

Nowadays football is widespread across the globe but people still associate it with ! the British Isles. This is probably due to the fact that the official history of football started there in 1863 when the Football Association in England was founded. However, the game is much older. Football was popular in Britain as early as the 2nd century A.D. Though football is considered a male sport, women play it too. The first ladies' teams appeared during World War I. Then the Football Association banned female competitions but the ban did not last long. In 1971 the ban was lifted and now female teams participate in domestic and international games.

The Black Sea is one of the favourite tourist destinations. It is popular with young people, families with children, and elderly couples. The mild climate and wonderful scenery make Black Sea holidays a very pleasant pastime. Another good thing about it is that the waters of the sea are quite safe. Though it is deep (some areas have a depth of 2200 metres), there are no dangerous creatures like sharks or poisonous jelly-fish in its waters. The Black Sea, however, has a lot of mysteries. The name is one of them. It is believed to have appeared in the 13th century, but there are different explanations of the name's meaning. Some scientists suppose that it means 'inhospitable', the others say black denotes the direction — the sea to the north.

The London climate is known for its mild character. Summer temperatures do no: normally go above 20 degrees. The city lies only 5 metres above sea level and that's why fogs are common there. The fog is formed by the steam or water concentrated in the air. A couple of centuries ago London fog had a funny name, the pea soup. In reality, it was not funny because the fog contained poisonous smoke from the factories. The mixture of fog and smoke was called smog. In 1952 thousands o: Londoners died from it. To improve the situation Londoners started to use oil instead of coal to heat their houses. They managed to get rid of the dangerous smoke.

For some people photography is a popular hobby or art. For others, it may be a job or art, but everyone agrees that the invention of the first camera was a great technological event. Amazingly, the first descriptions of a primitive camera were made by Chinese and Greek scientists in the 4th and 5th centuries B.C. However, the earliest photograph that has survived to the present day was taken only in 1826. It was a misty, black-and-white view from a window. Since then, technology has developed greatly. Now we have digital cameras to produce digital images and videos.

The Aurora8 Islands are a mystery in geography. They are marked on maps by tr.r letters E.D. This means that the islands disappear from time to time. First, they were discovered in 1762 not far from South America. Spanish sailors found the! islands and described them in detail. The central island was a peak covered with snow on one side. Two smaller ones lay close to it. However, later, English explorers failed to find the islands where they had been. They searched for them but without any success. Only once in 1856, an English ship noticed the islands. That time there were five of them and they were all covered with snow. That was the last report of the Aurora Islands.

Kew Royal Botanical Gardens are situated in the west of London. They house a collection of 50 000 plants, beautiful galleries and buildings. The history of the Gardens started in 1759. Through the centuries, the Gardens changed only for the better. Royal gardeners used special techniques for growing plants and designing the landscape. Many exotic flowers, bushes and trees were brought from abroad and planted there. They are now kept in greenhouses under appropriate conditions. The gardeners have worked hard to create the suitable climate inside. The beauty of Kew Gardens is open to the public. Londoners and tourists can enjoy flowering plants during regular exhibitions.

Greening's frog is mostly found in forests in Brazil. It was first described in 1896. It's unusual because the frog lives in tree holes. The small dark green animal has a massive flat head. The bones of the head have the form of a helmet covered with spines. To hide in their homes, Greening's frogs close the entrance to their holes with the helmet. This trick protects the frog from big animals and prevents it from losing much water. It is not easy to pull the frog from its hole. When attacked, the spines on the head become poisonous. Eating Greening's frog is like eating a poisonous cactus. The frog's poison is dangerous to humans too.