Special relativity is a theory that was created by a scientist named Albert Einstein. It states that space and time are connected in a way that depends on how fast you are going. This means that if one person is moving really fast and another person is standing still, they will experience time and space differently. For example, if one person is moving really fast, they might experience time passing slower than the person that's standing still. This is because the faster you move, the more stretched out time and space can become.