{Earth} Earth is Our Common Home

Earth, the third of the eight planets in the solar system, has a moon between Venus and Mars. The distance of the earth from the sun is set at one astronomical unit, about 150 million kilometers. Earth is the largest of the four rocky planets and the densest in the solar system. Earth is also the only place where life has been found with large amounts of oxygen. The earth is about 4.5 billion years old, perhaps as old as the solar system.

The topography of the earth

The biggest feature of the earth is that it is the only planet in the solar system to have liquid water on its surface. About 70% of the surface is covered by oceans, so it can support life. Looking back at the earth from space, we can see that the earth is a beautiful blue planet that surrounds the atmosphere. There are clouds of water in the atmosphere. Water has also been found in other parts of the solar system, but mostly in the form of ice.

In addition to the sea, is less land. The distribution of land on earth can be seen from space. Because of weathering, earth will not see many meteorite structures similar to those found on the surface of the moon and mercury. In addition to large craters, meteorite impacts on earth are gradually weathering away. Nevertheless, many large geological structures remain on the earth's surface.

From space, there is virtually no way to see the man-made structures on the ground, such as buildings, pyramids, or even the Great Wall, which claims to be the largest structure.




The surface environment of the earth

Earth is the only place in the solar system where life has been found so far (in 2007), and surface temperatures range from -60 to 50 degrees, not too hot or cold. Because the earth's axis of rotation is 23. The tilt is 44 degrees, so there are seasons. When the sun is direct at the northern hemisphere, it is summer in the northern hemisphere, while when the sun is direct at the southern hemisphere, it is winter in the northern hemisphere.

The earth's plates are still moving very frequently, and earthquakes are frequent, releasing energy. It is also an important feature of the earth that the thin crust moves horizontally with the convection of the mantle. The circulation of matter caused by plate movements has a great influence on the appearance of the earth.

One might ask why Venus, a sister planet of similar size to earth, is so different from earth's environment. The reason may be the result of the irreversible greenhouse effect. , presumably, the original Venus's composition is similar to the earth, but because of containing too much carbon dioxide in the atmosphere, the greenhouse effect makes temperature rise, the result of the carbon dioxide in the earth's crust also points to explain, more carbon dioxide and continue to deepen the effect of the greenhouse effect, as a result, in also cannot turn back, so called irreversible reaction.

The astral structure of the earth

The structure of the earth's interior can be roughly divided into three parts - the crust, the mantle, and the core. The crust and mantle are made up of silicates, while the core is made up of liquid (external) and solid (internal) iron-nickel alloys.

The earth's internal heat convection is still frequent, seismic volcanic activity is still ubiquitous, and because Taiwan is in an earthquake zone, the people of Taiwan should be one of the world's most frequently felt earthquakes.

The structure of the earth's atmosphere

The pressure on the earth is about one atmosphere. Consisting mainly of nitrogen and oxygen. High up there are white clouds of water. The atmospheric activity on the earth's surface is very obvious and active, and it is easy to see many cyclone structures. In summer, Taiwan is often hit by tropical cyclones (typhoons).

Earth's satellite

The earth has the moon, a disproportionately large moon about a quarter of the earth's radius. Jupiter and Saturn have moons larger than the moon, but are small objects compared to the planets themselves.



"The birth of the moon?
The most powerful explanation for the formation of the moon so far is the impact theory, which goes something like this: when the earth first formed, a mars-sized planet hit the earth, causing part of the earth to leave the earth, and about a month after the impact, the primitive moon was formed outside. This also explains why the moon is much less dense than the earth. There have been many experiments in Japan using computer simulations that support this hypothesis. The image on the left shows how the moon was created by the Japanese simulation experiment.

The distance of the moon from the earth is about 384,400 kilometers, which can be said to be very close. When observed from the earth, the brightness of the moon can reach -12.7, and its apparent diameter is about 0.5 degrees.

The moon is one of the most visited places in the world in 2007.

The moon is large, which means that the moon's gravity exerts a strong tidal force on the earth. At present, the moon and the earth are still not in equilibrium, the moon will gradually move away from the earth, and the earth's rotation will gradually slow down. It will not reach equilibrium until the moon orbits the earth five and fifteen days a week, and the earth rotates once for fifty-five days.

The observation information


As an earth person, you should be able to see the earth every day... ><
In addition, Google has an interesting software called Google Earth. You can view the map of the Earth in the computer, the terrain captured by the satellite and other information about the Earth. You can enjoy the feeling of overlooking the Earth.