What is second?
The second is the SI base unit of time. It is used globally in science, engineering, computing, and everyday life, and is the foundation upon which all other time units are built.
Real-world uses
The second is the SI base unit of time, fundamental to all scientific measurement, computing clock cycles, athletic timing, and GPS satellite synchronization. Everyday timekeeping, cooking timers, and traffic light cycles all rely on seconds.
History
The concept of dividing the day into 86,400 parts dates to ancient Babylonian and Egyptian timekeeping. Since 1967, the SI second has been defined as 9,192,631,770 periods of the radiation from a caesium-133 atom.
Common mistakes
Assuming a second has always been 1/86,400 of a day. The modern SI second is defined by caesium atom vibrations and is independent of Earth's rotation, which varies slightly due to tidal friction.
What is century (100 yr)?
A century is a unit of time equal to 100 years. It is used in historical analysis, long-term demographic and climate projections, and describing spans of civilizational or geological time.
Real-world uses
Centuries are used in historical periodization (e.g., "the 19th century"), long-term climate modelling, geological timeframes, and demographic trend analysis. Architectural preservation classifies buildings by the century of their construction.
History
The word "century" comes from the Latin "centuria," meaning a group of one hundred, used by the Romans for military units of approximately 100 soldiers. Its application to 100-year periods became common in European historical writing.
Common mistakes
The most common error is off-by-one: the 21st century began on January 1, 2001, not 2000, because there was no year zero. Also, confusing centuries with millennia (1,000 years) in historical discussions.
When is this conversion used?
Converting second to century (100 yr) is useful in the time domain when comparing values across different measurement standards or applying formulas that require a specific unit.
Worked examples
1 second = 3.170979e-10 century (100 yr)
1 century (100 yr) = 3.153600e+09 second
How to convert second to century (100 yr)
To convert second to century (100 yr), multiply the value by 3.170979e-10.
To convert century (100 yr) back to second, multiply by 3.153600e+09.
Measurement standards
The SI second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium-133 atom, maintained by the BIPM and national metrology institutes worldwide.
Did you know?
Earth's rotation is gradually slowing due to tidal friction with the Moon. To keep atomic time aligned with solar time, "leap seconds" have been inserted 27 times since 1972 — though they are scheduled to be abolished by 2035.
Quick reference: second to century (100 yr)
| second | century (100 yr) |
|---|---|
| 0.1 | 3.170979e-11 |
| 0.5 | 1.585490e-10 |
| 1 | 3.170979e-10 |
| 2 | 6.341958e-10 |
| 5 | 1.585490e-09 |
| 10 | 3.170979e-09 |
| 25 | 7.927448e-09 |
| 50 | 1.585490e-08 |
| 100 | 3.170979e-08 |
| 250 | 7.927448e-08 |
| 500 | 1.585490e-07 |
| 1,000 | 3.170979e-07 |
Common values
| second | century (100 yr) | |
|---|---|---|
| Blink of an eye | 0.3 second | 9.512938e-11 century (100 yr) |
| Average pop song | 210 second | 6.659056e-08 century (100 yr) |
| Feature film | 7,200 second | 0.00000228 century (100 yr) |
| One work day (8 hrs) | 28,800 second | 0.00000913 century (100 yr) |
| One calendar year | 31,536,000 second | 0.01 century (100 yr) |
Available Time units
More second conversions
- Convert second to minute
- Convert second to hour
- Convert second to day
- Convert second to week
- Convert second to year (365 d)
- Convert second to millisecond
- Convert second to microsecond
- Convert second to nanosecond
- Convert second to century (100 yr)
Assumption: year is defined as 365 days and century values are approximate.