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By:Sara Mei Merino

The Earth

The Earth is the third planet from the sun. Earth formed approximately 4.54 bilion years ago by accretion from the solar-nebula, and life appeared on its surface within one billion years. The planet is home to millions of species, including humans. The interior of the Earth is divided into layers, which are defined by their chemical or physical (rheological) properties. The Earth's terrain varies greatly from place to place. About 70.8%[99] of the surface is covered by water, with much of the continental shelf below sea level. Earth's rotation period relative to the Sun is 86,400 seconds of mean solar time (86,400.0025 SI seconds).

Conditions for life Water: Liquid water is the first condition for life. The temperature must be warm to keep water liquid.

Meteorogical features: The atmosphere and the ozone layer contribute to soften the temperatures. Life would not be possible under very extreme meteorological conditions such us strong winds, violent stroms or very severe volcano eruptions.

Atmosphere: The atmosphere and the ozone loyer protects us from solar harnful rays. It works like a green house.

Gravty: Eath's suitable gravity contributes to keep the atmosphere and the liquid in the oceans.

Chemical Compounds: Oxygen,

hydrogen, carbon and nitrogen are essential to enable life on a planet.

First living cells: The first living cells in Earth date from 3million years ago. They were unicellular beings that developed in water, similar to some algae we can find nowadays in the oceans. Bacteria were one of

the first forms of life on Earth as well. Those very simple forms os live developed themselves adapting their bo0dies to new habitat conditions and feeding habits. If you look at any animal, you will realise that its body is adapted to the place it lives and the food it eats.

My imaginary planet

My imaginay planet is called Fantasy because it is a very beatiful place. Fantasy is located in the milky way, 12 light-years away of the Earth. The orbit from the sun is of 3.652.564,98 kilometers. The planet is very big. Fantasy is made of: oxygen, carbon hydrate, atmosphere and plants. Fantasy has got two moons and a sun. In Fantasy the years have fifteen months and five hundred days. One day has 30 hours and you can see the Earth. It has plants, animals and living beings. The temperature of Fantasy is warm because the atmosphere of Fantasy is especial to control them.

The greenhouse effect

The greenhouse effect is a natural process that keeps the Earth at a temperature that is suitable for life. It is created by gases in the atmosphere that absorb heat. The problem is that the greenhouse effect is getting stronger. Several factors intervene in the greenhose effect, some natural and some created or at least augmented by humans activity.


1.-The sun has been radiatings energy for billions of years. The radiation of the sun travels very fast and reaches the Earth atmosphere in 8minutes. Some of this radiations passes through the atmosphere. 2.-However, some of these rays are reflected back in to space by the clouds and by particles in the atmosphere or is absorted by the greenhose gases. 3.-About half of the total of the incoming radiation is absorbed by the Earth surface. This has the effect os warming the atmosphere and the ground. 4.-As the surface of our planet heats up and gets warmer, it radiates head and radiation back to the atmosphere. 5.-Some os this radiations is absorbed and reflected by clouds ans the greenhouse and other gases in the atmosphere. 6.- The rest os the heat and radiations passes throug the atmosphere again is lost in space.

Solar system  

Is a book about the solar system.

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