Eclipse is a special astronomical phenomenon, which means that when the moon moves to the shadow of the earth, the area between the moon and the earth will be blocked by the earth because of the sunlight, and the moon will be missing. That is to say, at this time, the sun, the earth and the moon are exactly or almost on the same straight line between the sun and the moon, so the light from the sun to the moon will be blocked by the earth. As far as the earth is concerned, when an eclipse occurs, the directions of the sun and the moon will be different by 180 degrees. Ancient solar eclipse records can sometimes be used to infer the age of historical events. The ancient superstition in China was also called "dogs eat the moon". Eclipses can be divided into three types: partial eclipse, total eclipse and penumbral eclipse. When the whole moon enters the umbra, a total lunar eclipse will occur; But if only a part of it enters the umbra, only a partial lunar eclipse will occur. Total lunar eclipse and partial lunar eclipse are umbra eclipses.
During the total lunar eclipse, the moon is not completely invisible, because sunlight is refracted into the umbra when it passes through the thin atmosphere of the earth, and projected onto the surface of the moon, making the surface of the moon appear red copper. According to the path of the moon passing through the umbra and the atmospheric conditions of the earth at that time, the luminosity will be different in different total lunar eclipses.
Sometimes the moon does not enter the umbra, but only enters the penumbra. This is called a penumbral eclipse. During the penumbral eclipse, the moon will darken slightly, but its edge will not be blocked by the shadow of the earth. But you must watch the total lunar eclipse at night. The probability of watching a lunar eclipse is much smaller than that of watching a solar eclipse.
There is also a story about the solar eclipse:/kloc-At the beginning of the 6th century, Columbus sailed to Jamaica in South America and had a conflict with the local aborigines. Columbus and his sailors were trapped in a corner, without food and water. The situation is very critical. Knowing that there would be a total lunar eclipse that night, Columbus, who knew something about astronomy, shouted to the natives, "No food, no moonlight!" " In the evening, Columbus's words came true, and there was no moonlight. When the natives saw this scene, they were afraid, so they quickly made peace with Columbus.
-Watch out for global warming.
In recent years, people feel that the weather has suddenly become hot. The original cool autumn almost didn't start until the end of 10, and the hottest day in August actually reached more than 40 degrees. Why is this? It turned out to be human's own fault.
With the rapid development of human high technology, the side effects of science are gradually reflected, and global warming is an example. The weather is hot, and soaking in air conditioning in the heat has become a new "hobby", but have people ever thought about the negative effects of air conditioning? Of course, the answer is yes. The gas discharged from air conditioners contains a lot of methane, which is also a gas that causes global warming. At the same time, air conditioning will waste a lot of electricity, so try to avoid using air conditioning.
And another reason is: carbon dioxide! Automobile exhaust and factory exhaust contain a lot of carbon dioxide, which is the most likely to cause greenhouse effect (that is, global warming). There are more and more cars now. According to statistics, by 2 1 century, there will be 700 million cars in the world, and a large amount of exhaust gas will seriously affect us, such as cough and pharyngitis ... The most important thing is global warming. Statistics show that the per capita carbon dioxide emissions in the United States have reached 20 tons a year! China's annual per capita carbon dioxide emissions are also 2.5 1 ton a year! The environment around us is undergoing serious changes.
The more important reasons are: sharp decline of forests, destruction of water resources, serious destruction of ecological chain, barren land and serious water pollution. According to statistics, 65,438+00% of the rivers in the world are polluted, and the supply of fresh water has become a problem. At the same time, due to the extensive use of minerals, the burning CO2 gas caused air pollution, and the ozone layer was severely damaged, and ozone holes appeared in the north and south poles, which aggravated the environmental deterioration. This vicious circle will eventually lead to a serious impact on people's lives.
What kind of tragedy is this? Of course it is obvious! The weather is getting hotter, the sea level is rising, the glaciers in the North and South poles are melting, and coastal cities and island countries are flooded. All these have seriously affected the survival of mankind. Experiments show that the sea level will rise by more than half a meter in the next 300 years, which is still the most optimistic data. In another seven years, global warming will continue irreversibly. What is even more frightening is that due to the melting of the Arctic ice, rainfall has increased, and a large amount of fresh water has flowed into the North Atlantic, destroying the Mexican warm current. Once the Mexican warm current is cut off, the temperature in northwest Europe will drop by as much as 5-8 degrees, which will probably lead to a new ice age! I'm sure you've seen the film The Day After Tomorrow. The scene in the play is a true portrayal of our planet hundreds of years later: tornado, ice crack, sudden drop of temperature, ice storm, freezing rain, earthquake, flood, tsunami ... This is not a crazy fantasy, but it will become a reality if human beings don't stop destroying the environment! Global warming is not only hot weather, but also many negative effects!
In order to save the earth, we should try our best to do it: don't turn on the air conditioner, use recycled environmental protection paper, discard meat (steak) food (the digestion of cattle contains nitrous oxide, if you become a vegetarian, reduce carbon dioxide emissions 1.5 tons every year! ) instead of plastic bags, take the bus ... every bit of life. In fact, environmental protection is not difficult. As long as you support environmental protection, that is your best gift to the planet. You don't need too many words. As long as everyone acts, it will be a powerful force! Today, Japan, Britain, the United States and other countries have taken action. Although we have taken action, it is still not enough for a big country with a population of 654.38+0.3 billion.
Therefore, being alert to global warming is the only way for all mankind to save the earth. Some people may say: can't we move to other planets? The answer is yes, but how many people can it accommodate? Some people say that the funds for controlling the greenhouse effect are too large, which is sky-high for finance. However, if we keep dragging on, the final result will be that our planet is beyond recognition, not to mention finance, and even our own lives will be in danger! Therefore, environmental protection should not just stay in words, but should really be implemented in action.
Yes
Lunbu turned an arm into a jade.