Can the blind differentiate between night and day?

As anyone knows who has traversed nine or ten time zones in an airplane and ended up with a bad case of jetlag knows, the body clock doesn't rely very much on light and dark. In fact, in modern times, we get very little biological signal of night and day from our eyes, due to artificial lighting. read more

Day vs Night . The difference between day and night literally means the difference between day time and night time. A day consists of both day time and night time. The period between the sun rise to the sun set is called the day time. read more