I found the following theory in one of the my old notebooks. I wrote this as a child and I do not remember writing it and where I got the information I used. I would to get this theory published. "Actually every planet has mobile creatures which may be made mobile or immobile by a certain amount of heat from a burning fire (sun energy). Actually all these creatures depend on each other from planet to planet, but it seems like the creatures in planet with high temperature are more powerful than the ones in planets with low temperatures and this makes the planet mercury the planet with the most powerful creatures followed by Venus the Earth, the ones in Mars, Asteroids, Jupiter, Saturn, Uranus, Neptune and Pluto. The creatures powerful than the ones in planet Earth don't cope very well in the planet Earth before their adaptation which makes them easily controllable during their first evolution stages. Powerful here means the level of activity of a decided action like reproduction. A powerful creature here may mean a creature that reproduces itself by asexual reproduction and that creature can reproduce itself many times within a short interval of time. Take an example of some bacteria that reproduce asexually every 20 minutes while a human being reproduces sexually every 9 months. The bacteria will have multiplied thousand times before the human being multiplies by two."