The Solar System and the Earth

There are a great number of things without which it is impossible for a human to survive. One of the most essential of these is the solar system. If even a small change takes place within this system consisting of plain gaseous rocks, the whole humanity will end without a moment's delay. Hence I feel that it is necessary for us to know about and to understand the Solar System.

Lets get a the concept of the placement of planets in the solar system first.

Look at the picture on your right, the bright thing you see in the left hand corner is of course the sun. The round ball closest to the sun is the planet Mercury, then there is Venus, the Earth and then Mars. After that you can see a ring of asteroids, these asteroids define the inner planets and the outer planets. The outer planets include Jupiter that is the first planet outside the asteroid ring and then there is Saturn, then Uranus, Neptune and then finally there is another ring of asteroids which defines the end of the solar system.

The difference between the orbit and axis:
The orbit is the track of each planet as it goes around the sun or revolves around it, one revolution equals to one earth year.
The axis is the way in which a planet rotates, a rotation equals one day.

The Sun:
The sun is a huge ball of gas or a star. It along with other smaller stars present in the solar system is the source of heat and light for all the planets. As it is in all stars, fusion reactions also take place in the sun. During fusion two smaller atoms fuse together to form a bigger atom and this releases huge amounts of energy, which is the reason of blasts in the sun and all the fire we see in it and all the heat it radiates. According to recent researches the sun's diameter increase by 20% every 4 billion years due to fusion reactions.

The planets and Why earth is best for us:
Even tough microbots have been released onto Mars in the hope of sending humans their too, up till now Mars and Mercury are too warm for humans to live there. Venus the remaining inside planet is extremely cold and the gasses present in its atmosphere are harmful for humans. The outside planets are also cooler, darker and the have a lot of gravitational field strength which barely allows humans to walk. Therefore as they Earth is most temperate for humans with just the right amount of heat, light and gravity it is the best for us.

The Earth's atmosphere acts as a protective layer for us. It filters the radioactive gasses and other harmful rays which come from the sun and other stars. However the same radioactive emissions are now emitting from the earth due to new technology such as the nuclear power plant. This is harming both humans, animals and trees. The waste from such sources in thrown into rivers which has caused the genders of fishes to change, the air is also polluted which results in the decrease in the number of small birds like the sparrow and robin...