Years to Millennia (yr to ky)
1 year equals 0.001 millennia exactly.
How to convert years to millennia
To convert years to millennia, multiply the number of years by 0.001. This factor is exact. To go the other way, multiply millennia by 1,000.
millennia = years × 0.001
Example: 10 years = 0.01 millennia.
Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.
About these units
Year (yr)
The average Gregorian calendar year of 365.2425 days (31,556,952 seconds). A common year has 365 days and a leap year 366.
A year is the Earth's trip around the Sun, but there are several versions. The tropical year, which tracks the seasons, is about 365.2422 days. The sidereal year, measured against the stars, is about 365.2564 days, roughly 20 minutes longer, because the Earth's axis precesses. Calendars must squeeze these into whole days, which is the origin of leap years. English year descends from Old English gear, while Latin annus, the source of annual, comes from a different root.
The Gregorian calendar, introduced by Pope Gregory XIII's bull of 24 February 1582, fixed the problem of Julian drift that had moved the March equinox away from 21 March and upset the date of Easter. Ten days were skipped, so Thursday 4 October was followed by Friday 15 October. Its rule of skipping leap days in century years not divisible by 400 gives a mean year of 365.2425 days, the value this site uses for the year. Britain and its empire switched in 1752 and Russia in 1918. Scientists write the year as a, with the Julian year fixed at 31,557,600 seconds.
1 year = 31,556,952 seconds (exactly).
Sources: Wikipedia: Year; Wikipedia: Gregorian calendar
Millennium (ky)
One thousand years.
Latin supplied the parts of millennium: mille, a thousand, and annus, a year. The plural can be millennia or millenniums. Because a thousand years exceeds any one person's reach, the word acquired religious overtones in the idea of millenarianism, though the unit itself is a plain count of years. When the year 2000 arrived, a new question came with it: was this the start of the third millennium, or was that a year away?
A millennium is 1,000 years, here 1,000 average Gregorian years. The 2001 camp points out that there is no year zero, so the first millennium ran from year 1 to year 1000. The 2000 camp followed the odometer effect, in which the hundreds and thousands digits roll over together. Most people celebrated in 2000, and the celebrations in 2001 were mostly routine, although the U.S. Naval Observatory, Cuba and Japan did mark the strict date. The evolutionary biologist Stephen Jay Gould observed that the strict view dominated at the start of the 20th century and the popular view at its end.
1 millennium = 31,556,952,000 seconds (exactly).
Sources: Wikipedia: Millennium; Wikipedia: Millenarianism
Related conversions
- Millennia to years (reverse)
- Years to seconds
- Years to minutes
- Years to hours
- Years to days
- Years to weeks
- Years to months
- Years to milliseconds
- Years to microseconds
- Years to nanoseconds
- Years to decades
- Years to centuries
- Years to picoseconds
- Seconds to millennia
- Minutes to millennia
- Hours to millennia
- Days to millennia
- Weeks to millennia
- Months to millennia
- Milliseconds to millennia
- Microseconds to millennia
- Nanoseconds to millennia
- Decades to millennia
- Centuries to millennia
See all time units.