Special Relativity

Although the word “relativity” is synonymous with Albert EinsteinEinstein, Albert, Galileo Galilei was actually the first scientist to formulate what we now call “the principle of relativityPrinciple of relativity”. In his famous Dialogue (1632), GalileoGalileo suggested to his readers that they should shut themselves up in the cabin of a ship, below the decks, so that they could not see what was going on outside. He argued that they would not be able to tell whether the ship was stationary or moving, as long as the motion was uniform (that is, at a constant speed) and in the same direction, without any turns. While the ship was the vehicle of choice in Galileo’s time, all of us can recall a similar experience in a train or an airplane. When the ride is smooth and you do not look outside, you cannot tell whether you are moving or not.