Tropical Years to Seconds (yr (trop) to s)
1 tropical year equals 31,556,925.22 seconds (rounded).
How to convert tropical years to seconds
To convert tropical years to seconds, multiply the number of tropical years by 31,556,925.22. The factor is rounded to 10 significant digits. To go the other way, multiply seconds by 3.16887654×10⁻⁸ (rounded).
seconds = tropical years × 31,556,925.22
Example: 10 tropical years = 315,569,252.2 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.
Approximate value. Standards for the tropical year varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.
About these units
Tropical Year (yr (trop))
About 365.24219 days, the time between successive spring equinoxes. The Gregorian calendar approximates it.
Tropical comes from a Greek word meaning turning, and this year is measured by the cycle of the seasons: the time for the Sun to return to the same ecliptic longitude. The mean value at the start of 2000 was 365.2421897 days, or 365 days 5 hours 48 minutes 45.19 seconds. Individual intervals between March equinoxes wander by minutes, so the mean is what is normally quoted.
Hipparchus timed equinoxes in the second century BC and arrived at 365 days 5 hours 55 minutes 12 seconds, a little long. The Alfonsine Tables of 1252 gave 365 days 5 hours 49 minutes 16 seconds, and this value guided the Gregorian reform of 1582, which was needed because the equinox had slipped about ten days from its date at the Council of Nicaea in 325.
Kepler's Rudolphine Tables of 1627 came within a second or so of the modern figure, and Simon Newcomb's 1898 value of about 365.24219878 days served the national almanacs until 1983. The Gregorian calendar averages 365.2425 days, which tracks the tropical year closely.
1 tropical year = 31,556,925.22 seconds (approximately).
Sources: Wikipedia: Tropical year; NASA Earth Fact Sheet
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 tropical years (reverse)
- Tropical years to minutes
- Tropical years to hours
- Tropical years to days
- Tropical years to weeks
- Tropical years to months
- Tropical years to years
- 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
- Millennia to seconds
See all time units.