Earth and beyond

spinning and orbiting Earth

days and years

a good calendar

the best calendar so far

a simple, but bad, calendar

days and years

Calendars, days, years, leap years, days in a year. Good grief! It's tempting to say "Who cares?". Actually, every time you look at a calendar you should be glad someone puzzled over how many days there are in a year. Look at the mess the Romans got into without a proper calandar.

		The first attempts at producing a calendar didn’t make sure the calendar matched the seasons. Check out our section ‘A simple but bad calendar’ to see what a mess you can get into. In Julius Caesar's time (a few years BCE) the calendar and seasons had slipped so much that mid-winter was in September! Caesar ordered 90 days to be added to the year 46 BCE just as a temporary fix. Leaders had real power in those days!

To create a reliable and consistent calendar we have to have an accurate answer to the question:
‘how many times does the Earth rotate (a day) during one orbit around the Sun (a year)?’
We now know that the Earth takes just over 365 (365.2422) days to orbit the Sun. But we haven't always known that number accurately, and not knowing it accurately can cause real problems.

To find out about a good calendar click here

To find out about the best calendar so far click here

To find out about a simple, but BAD, calendar click here



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