1 year ago
Last edited at 10:24PM on 7/20/2012
If you are talking of length of day(light) it varies by time of the year, latitude (place your are upon the earth), etc. And that is if you are talking about the earth - if you talking about a different planet or star, then there other factors that come into effect. To be more specific in the answer, the question has to be more specific : ) Generally, you could say a day is the time period of rotation on the body you are speaking of, but other factors still come into effect.