<P> In common usage , it is either an interval equal to 24 hours or daytime , the consecutive period of time during which the Sun is above the horizon . The word day may also refer to a day of the week or to a calendar date , as in answer to the question , `` On which day ? '' The life patterns ( circadian rhythms ) of humans and many other species are related to Earth 's solar day and the day - night cycle . </P>
<P> In common usage , it is either an interval equal to 24 hours or daytime , the consecutive period of time during which the Sun is above the horizon . The word day may also refer to a day of the week or to a calendar date , as in answer to the question , `` On which day ? '' The life patterns ( circadian rhythms ) of humans and many other species are related to Earth 's solar day and the day - night cycle . </P>
1 solar day is equal to how many hours
1 solar day is equal to how many hours
24 hours
24 hours