Today we remember Pope Gregory XIII and his team of mighty astronomers, who spearheaded the calendar reform and change from the old-style Julian calendar, invented by the Romans, to the calendar we use today.
Funny, but back in fifth grade I was taught that a year was 365.25 days, and apparently that was what old Julius Caesar thought, but he was wrong. It turns out a year is ACTUALLY 365.2425 days, who knew? Which means that century years like 2000, divisible by 400, AREN’T leap years. Anyway, long story short, by the 1500’s Easter had drifted off by about two weeks, and they instituted the Gregorian calendar reform, which was slow to take hold across Europe because naturally most of the Protestant countries were suspicious of anything Catholic.
In addition to setting up the current system of leap years etc. which we use today, the start of the calendar year was officially moved to January 1. Thanks, Pope Gregory!
So here’s to all the astronomers and calendar-makers throughout the years. Especially let us remember our Mayan friends. Happy 2012.
Some favorite astronomers, and some books about them:
Pinkney, Andrea Davis. Dear Benjamin Banneker. San Diego: Harcourt, 1994. (32 pages; Reading Level: Grades 1-3).
Sis, Peter. Starry Messenger: A Book Depicting the Life of a Famous Scientist, Mathematician, Astronomer, Philosopher, Physicist, Galileo Galilei. NY: Farrar, 1996. (30 pages, Reading Level: Grades 3-6+) (Beautiful and poetic. A treasury for young and old alike. I love this book!)
McPherson, Stephanie Sammartino. Rooftop Astronomer: A Story About Maria Mitchell. Minneapolis: Carolrhoda Books, 1990. (64 pages; Reading Level: ~third grade)