Synodic Months to Seconds (mo (syn) to s)
1 synodic month equals 2,551,442.976 seconds exactly.
How to convert synodic months to seconds
To convert synodic months to seconds, multiply the number of synodic months by 2,551,442.976. This factor is exact. To go the other way, multiply seconds by 3.919350773×10⁻⁷ (rounded).
seconds = synodic months × 2,551,442.976
Example: 10 synodic months = 25,514,429.76 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 synodic month varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.
About these units
Synodic Month (mo (syn))
About 29.53 days, the time from one new moon to the next. The basis of lunar and many religious calendars.
A synodic month is the span from one new moon to the next, when the Moon returns to the same position relative to the Sun as seen from Earth. Its mean length is about 29.53 days, or 29 days 12 hours 44 minutes 3 seconds. The word synodic derives from a Greek term for meeting, since the Sun and Moon meet in the sky at each new moon.
Individual months are far from equal. Because the Moon's orbit is elliptical and the Sun perturbs it, a single lunation can run from about 29.27 to about 29.83 days, and in a given year the interval can differ from the mean by up to roughly seven hours. In 2001, for instance, lunations ranged from 29 days 19 hours in January to 29 days 7 hours in July.
Babylonian astronomers were the first to recognise this kind of month and to work out its mean length, and the quantity still underlies lunar and lunisolar calendars such as the Islamic, Hebrew and Chinese ones. It is longer than the sidereal month of about 27.3 days because Earth moves along its orbit while the Moon circles it.
1 synodic month = 2,551,442.976 seconds (approximately).
Sources: Wikipedia: Lunar month
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 synodic months (reverse)
- Synodic months to minutes
- Synodic months to hours
- Synodic months to days
- Synodic months to weeks
- Synodic months to months
- Synodic months 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.