When the body and mind are isolated away from noise, light, and gravity’s effects, you give yourself a chance to truly relax. During this time, the brain can enter what’s called the Theta State, which is a period of slower brain wave activity – you experience this all the time just prior to falling asleep or when you daydream. People who are prone to bursts of creativity in this state have reported seeing colors/imagery, or hearing music/sounds; but it’s entirely up to what your brain would do anyway, and is not like taking a hallucinogen.