【推荐2】“Is there life out there?” is a question which scientists are trying to answer. They look for life in space. In recent years, they have turned their attention to Europa, the sixth closest moon of Jupiter (木星).

Europa is a little smaller than the moon and is covered by ice. Its surface is too cold for anything to live there. Scientists want to know what lies under the ice, for that is where any life on Europa would most likely be.

For years, scientists believed all life on the earth depended on the sun. The discovery of chemosynthetic (化学合成的) life has changed scientists’ idea—planets with oceans (海洋) and hydrothermal vents (热液喷口) might also support life.

Europa does have oceans. In fact, Europa appears to have more oceans than the earth does. The ice on this moon’s surface covers what appears to be moving water. Do these oceans have hydrothermal vents? Scientists do not know yet. If they do, the oceans of Europa might support life. Only a space travel to Europa would tell for certain.

Scientists are studying the closest possible environment they can find on the earth: Lake Vostok. Like Europa’s oceans, Lake Vostok is miles under a frozen surface. It does not receive direct sunlight, either.

So like Europa, the lake cannot support photosynthetic (光合作用的) life. If scientists find life in the lake, it would support the idea that there might also be life on Europa.

【推荐1】

Lake Baikal, located in Siberia, Russia, is the world’s deepest and largest freshwater lake, holding 22% of Earth’s fresh water. Known as the “Pearl of the World”, for Russia, it’s a root of national pride because of its rich natural resource.

The depth of Lake Baikal was first surveyed (勘测) in 1797. Some workers from factories in Altai found out that the lake was 1, 238 meters deep. Since then, a number of surveys of Lake Baikal had been taken, but with ropes only. The exact depth of Lake Baikal was not agreed on until 1992, when the USSR Ministry of Defense tried sound waves to accurately (精确地) survey the deepest point and by using them, they found it is 1, 642 meters deep.

Although the lake is very deep, its water is high in oxygen, meaning plants and animals survive at all depths in the lake. In fact, Lake Baikal is home to more types of plants and animals than any other lake in the world—more than 3, 600—many of which cannot be found anywhere else.

Like many other natural places, Lake Baikal is in trouble because of human activities and climate change. Since 1892, winter temperatures around Lake Baikal have warmed by 0. 5 °F (0. 3 ℃) every ten years, making this one of the most rapidly warming parts in the world. Baikal’s coastline has been polluted by an ever-growing number of tourists.

As one of nature’s most prized treasures, Lake Baikal needs to be valued, honored and protected to keep on shining bright.

【推荐3】The Black Box is also called a Flight Data Recorder of an Airplane. It is an instrument that records all the activities happening in the aircraft in the time period of its flight.

From the security point of view, this box is generally kept at the backside of the aircraft. People search for the black box as soon as any flight crashes or goes missing. This box is made of Titanium metal and is enclosed in a Titanium box which gives it the strength to withstand any shock if it falls in the sea or falls from the height.

Earlier it used to be red in colour and was known by the name “Red Egg”. In the early days, its inner walls were black in colour, so it came to be known as a “Black Box”. These boxes are red or pink in colour so that they can be found easily.

This box can contain information about direction, altitude, fuel, speed, turbulence, cabin temperature etc. It can work at a temperature of about 11000°C for one hour and a temperature of 260°C for 10 hours. Since the box can work for 30 days without any electricity, it keeps on emitting the waves along with a beep sound for about 30 days when it is lost anywhere.

Though a black box does not reflect a clear picture of plane accidents and in some of the accidental cases it could hardly be found, but one fact is for sure that it plays an important role in the investigation of plane accidents.