Gravity is a phenomena of the physical world. We can observer this phenomena when an object falls to the ground, or in ourselves standing up on the surface of the Earth. Gravity is responsible for tides, keeping our satellite and natural satellites in orbit, planet formation, their orbits around the Sun, ... . Gravity can be observed at grater scales giving structure to galaxies and clusters in the universe. It gathers gas into nebulosas, where hydrogen compacts creating the conditions for nuclear fusion and the birth of stars. It gives us the most mysterious and exotic places and events in the universe: gravitational lensing, supernovas, neutron stars, and blackholes!. Some ideas about gravity Early in the 17th century Galileo Galilei discovered that every object will accelerate in the same amount when falling to the ground, and he proposed his basic principle of relativity. The idea was a constant for gravity that was explored during the second half of the 17th century [^1]. The...