The attraction of heavenly bodies and astrology

People have always believed weird things. Since we are human beings, our anxiety to find answers to our questions makes us develop scientific knowledge, but it also makes us feel distressed when we cannot find those answers, turning our distress into myth and pseudoscience in the form of magic, tarot, ghosts, astrology or mythology. As our knowledge progresses, some of these fantastic explanations disappear, as it was the case of our belief that thunder is an expression of gods’ hostility when we do things wrong.
However, some of these believes are still present in our minds and we use science-like language to legitimize those explanations into gullible ears.
Astrologists, for instance, talk about the force of heavenly bodies to justify their influence on our character and our life, using the science-like language of gravitational attraction. Newton’s laws are quoted in astrology books a much as in astronomy books.
Well then, let’s check it. According to astrologists, Mars’ gravitational attraction is one of these forces having such a strong influence at the time of our birth that it may mark our life for good. Mars is a planet a little bit smaller than the Earth, with a mass of 6 x 10²³ kg at 7.7 x 10¹⁰ metres away from us. Therefore, according to Newton’s law of gravitation (there is a gravitational force between any two bodies in the universe, which is proportionally greater in function of their mass and proportionally smaller in function of their distance), Mars exerts a force of 6.8 x 10-8 kg on any person weighing 100 kg located on the surface of the Earth. Funnily enough, Mars’ force is exactly the same as any other person’s weighing 220 pounds (100 kg) standing at a distance of just 3 feet. Therefore, here we have another axiom for astrology:
"If Mars’ gravitational force exerts any influence on our character when we are born, the influence of the gravitational force of a chubby midwife standing three feet from us would be even greater. And the gravitational force of the walls in the operating room would be so significant that they would affect our character for good."

Sources:

1.  Michael Shermer. Why people believe weird things.  http://www.michaelshermer.com/weird-things/ 
2. A good introduction to the mechanisms making us believe in pseudoscience and other believes without scientific grounding. http://en.wikipedia.org/wiki/Gravitation 
3. The data about the attraction exerted by Mars and by a 220-pound person are quoted from A scientist by the seashore, by James S. Trefil, a popular science book teaching physics about what we can see and experiment on a beach. http://www.amazon.com/Scientist-Seashore-Dover-Science-Books/dp/048644564X 
4. Carl Sagan’s quote on obstetricians and astrology:  http://en.wikiquote.org/wiki/Carl_Sagan