We know that summer produces the longest days. But for one day, can 99% of the Earth’s population be in sunlight, at least for a moment?

That was the premise of an article published on TimeandDate.com — “Fact Check: 99% of the World’s Population Gets Sunlight at the Same Moment on July 8” by Konstantin Bikos (https://www.timeanddate.com/news/astronomy/99-percent-sunlight-july-8). Could this be true?

According to the Day and Night World Map for July 8th, almost all of the world’s most populated areas — North America, South America, Europe, Africa, and most of Asia — receive some sunlight at 11:15 UTC. Based on 2022 population data from the Center for International Earth Science Information Network at Columbia University, it’s nighttime for just under 80 million people at that time and date, which means the rest of us — about 7.7 billion people or 99%, are illuminated by the Sun. This further breaks down to 83% getting direct sunlight and another 16% getting indirect sunlight.

There is one glitch — a few hundred million people on the sunlit side will be on the outermost edge of the twilight zones, called astronomical twilight. Here the Sun is actually 12-18 degrees below the horizon, so the indirect sunlight becomes so thin that it usually can’t been seen. So about 3% will still think it’s night.

But technically, the statement that 99% of the world’s population will be in some form of sunlight at 11:15 UTC on July 8 is correct.