Galileo Galilei was an Italian astronomer and physicist who lived in the 16th and 17th centuries. He is considered one of the pioneers of modern science, and his thought experiment involving a windowless ship on a calm sea is one of his most famous contributions to the field of physics. The basic idea of the thought experiment is to imagine a person inside a ship that is moving at a constant speed and direction, with no external references available to the person. The question posed is whether the person could determine whetherthe ship is moving or not, based solely on their own sensory experiences. Galileo's conclusion was that the person could not determine if the ship was moving or not. According to him, the laws of physics are the same in all inertial frames of reference, which means that the same experiments will produce the same results regardless of the relative motion of the observer. As a result, there is no way forthe person inside the ship to determine if they are in a state of rest or a state of uniform motion. Step 2/2 /\\ This idea was a major departure from the prevailing Aristotelian view, which held that objects in motion needed a continuous force to maintain their motion. Galileo's argument helped to lay the foundation for classical mechanics and the theory of special relativity, both of which are based on the principle of relative motion. In mathematical terms, Galileo's idea can be expressed using the principle of Galilean invariance. This principle states that the laws of physics are the same in all inertial frames of reference and that the relative velocity between two such frames is constant. This is expressed mathematically as follows: I v : v v0 where v is the velocity of a particle in one frame of reference, v0 is the velocity of the other frame of reference, and v' is the relative velocity between the two frames. In summary, Galileo Galilei's thought experiment involving a windowless ship on a calm sea is a key contribution to the field of physics. It challenged the prevailing Aristotelian view and helped lay the foundation for classical mechanics and the theory of special relativity. The mathematical expression of this idea, the principle of Galilean invariance, is still widely used in physics today