Because the Earth is always turning on its axis, we have periods of day and night. To establish consistent times for daylight and darkness, humans have divided the Earth into 24 time zones. At one point we call the International Dateline, the days divide.
As you travel around the world east to west, the time becomes earlier. As you go west to east, it becomes later. In the United States, the time on the west coast is three hours earlier than the time on the east coast. At some point on the Earth, the time has to change by 24 hours. We call that the International Dateline (IDL) and it runs from pole to pole through the middle of the Pacific Ocean. A new day, or a new year, always arrives first on the west side of that line. Then it progresses around the Earth, hour by hour until it returns to the east side of the IDL.
The Earth always has day and night at the same time because it’s a rotating sphere. People in antiquity didn’t understand that. Also in ancient times when people did not have electric lights, they worked only during the day and slept at night. However, 2000 years ago Jesus talked about an event that will take place in an instant, but he said that it will be daytime and it will be nighttime. He also said that some people will be working (daytime activity) and others will be sleeping (nighttime activity) when the event takes place.
You can read the words of Jesus in Luke 17:30-35. How did He know that day and night take place at the same time? I think it was because he was more than a man. In fact, I believe He created day and night. (See John 1:1, 2, 14.)
–Roland Earnst © 2018