Millennia to Seconds (ky to s)
1 millennium equals 31,556,952,000 seconds exactly.
How to convert millennia to seconds
To convert millennia to seconds, multiply the number of millennia by 31,556,952,000. This factor is exact. To go the other way, multiply seconds by 3.168873851×10⁻¹¹ (rounded).
seconds = millennia × 31,556,952,000
Example: 10 millennia = 315,569,520,000 seconds.
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
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
Second (s)
The SI base unit of time, defined by the radiation frequency of the cesium-133 atom: 9,192,631,770 cycles per second.
Our word second is a leftover of Latin. Medieval scholars divided a degree, and later the hour, into 60 parts called pars minuta prima, the first small part, and divided those again into pars minuta secunda, the second small part. NIST traces the roots further back: Babylonian and Greek astronomers split the circle into 360 degrees, and around 150 C.E. Ptolemy split each degree into 60 minutes and each minute into 60 seconds. Clocks that could show seconds appeared only in the later 16th century, and Christiaan Huygens's pendulum clock of 1656 was the first able to keep time accurately to the second.
For most of history the second was a fraction of a day, and in 1956 it was redefined as a fraction of the tropical year, a definition the SI took over in 1960. In 1967 the 13th CGPM switched to atoms: 9,192,631,770 periods of the radiation tied to a hyperfine transition of caesium-133. The 2019 SI revision restated this by fixing the caesium frequency at 9,192,631,770 hertz. NIST reports that commercial caesium clocks stay within about a three-millionth of a second per year, and experimental clocks based on other atoms are roughly ten thousand times more precise.
The second is the reference unit for time on this site.
Sources: NIST: the second and the SI redefinition; BIPM: SI Brochure, 9th edition; Wikipedia: Second
Related conversions
- Seconds to millennia (reverse)
- Millennia to minutes
- Millennia to hours
- Millennia to days
- Millennia to weeks
- Millennia to months
- Millennia to years
- Millennia to milliseconds
- Millennia to microseconds
- Millennia to nanoseconds
- Millennia to decades
- Millennia to centuries
- Minutes to seconds
- Hours to seconds
- Days to seconds
- Weeks to seconds
- Months to seconds
- Years to seconds
- Milliseconds to seconds
- Microseconds to seconds
- Nanoseconds to seconds
- Decades to seconds
- Centuries to seconds
- Picoseconds to seconds
See all time units.