# Orders of magnitude (time)

An **order of magnitude** describes the link between two different amounts. The difference between each amount step is usually 10, with each order being either 10 times greater or 10 times smaller than the next amount. This makes the scale easy to manipulate using logarithms. For time units, the difference between the smallest limit of time, the Planck time, and the next order of magnitude is larger than 10. A second is 60 t, a minute is 60 seconds, an hour is 60 minutes, a day is 24 hours, a week is 7 days, a month is 4 weeks, a year is 12 months, a millennium is 1,000 years, etc...

## Seconds

Orders of magnitude in seconds (time)| Factor (in seconds) | Time Unit Multiples: | Time Unit Symbol: | Time Unit Definition: | Comparative examples & common units of time: | Orders of magnitude: |
| --- | --- | --- | --- | --- | --- |
| 10−44 seconds | 1 Planck Time | tP | **Planck Time** is the time required for light to travel a distance of 1 Planck length in vacuum. | - | - |
| 10−30 seconds | 1 quectosecond | qs | **Quectosecond**, (*quecto* + *second*), is one nonillionth (in the short scale) of a second. | - | 1 qs and less, 10 qs, 100 qs |
| 10−27 seconds | 1 rontosecond | rs | **Rontosecond**, (*ronto* + *second*), is one quintillionth (in the long scale) or one octillionth (in the short scale) of a second. | **300 rs**: Average lifetime of W and Z bosons | 1 rs, 10 rs, 100 rs |
| 10−24 seconds | 1 yoctosecond | ys | **Yoctosecond**, (*yocto* + *second*), is one quadrillionth (in the long scale) or one septillionth (in the short scale) of a second. | **0.3 ys**: mean life of the W and Z bosons. **1 ys**: time for top quark decay. **1 ys**: time taken for a quark to emit a gluon. **91 ys**: half-life of lithium-4. | 1 ys, 10 ys, 100 ys |
| 10−21 seconds | 1 zeptosecond | zs | **Zeptosecond**, (*zepto* + *second*), is one sextillionth of a second. | **7 zs**: half-life of helium-9's outer neutron in the second nuclear halo. **17 zs**: approximate period of electromagnetic radiation at the boundary between gamma rays and X-rays.
**247 zs**: The experimentally-measured travel time of a photon across a hydrogen molecule **300 zs**: approximate typical cycle time of X-rays, on the boundary between hard and soft X-rays | 1 zs, 10 zs, 100 zs |
| 10−18 seconds | 1 attosecond | as | **Attosecond** is one quintillionth of a second. | **100 attoseconds**: shortest measured period of time. | 1 as, 10 as, 100 as |
| 10−15 seconds | 1 femtosecond | fs | **Femtosecond** is one quadrillionth of a second. | cycle time for 390 nanometre light, transition from visible light to ultraviolet | 1 fs, 10 fs, 100 fs |
| 10−12 seconds | 1 picosecond | ps | **Picosecond** is one trillionth of a second. | **1 ps**: half-life of a bottom quark **4 ps**: Time to execute one machine cycle by an IBM Silicon-Germanium transistor (supercomputer) | 1 ps, 10 ps, 100 ps |
| 10−9 seconds | 1 nanosecond | ns | **Nanosecond** is one billionth of a second. | **1 ns**: Time to execute one machine cycle by an Intel Pentium 4 1 GHz microprocessor **1 ns**: Light travels 12 inches (30 cm) **1,000,000,000 nanoseconds**: 1 second | 1 ns, 10 ns, 100 ns |
| 10−6 seconds | 1 microsecond | µs | **Microsecond** is one millionth of a second. | sometimes also abbreviated µsec **1 µs**: Time to execute one machine cycle by an Intel 80186 microprocessor **4-16 µs**: Time to execute one machine cycle by an older minicomputer | 1 µs, 10 µs, 100 µs |
| 10−3 seconds | 1 millisecond | ms | **Millisecond** is one thousandth of a second. | **50-80 ms**: The time taken to blink an eye | 1 ms, 10 ms, 100 ms |
| 10−2 seconds | 1 centisecond | cs | **Centisecond** is one hundredth of a second. | - | 1 cs, 10 cs, 100 cs |
| 10−1 seconds | 1 decisecond | ds | **Decisecond** is one tenth of a second. | - | 1 ds, 10 ds |
| 100 seconds | 1 second | s | - | **1 second (s)**: "One Mississippi" said aloud **60 seconds (s)**: 1 minute | 1 second, 10 seconds, 100 seconds |
| 101 seconds | 1 decasecond (10 seconds) | das | **Decasecond** is ten seconds. | **6 decaseconds (das)**: 1 minute | 101 seconds |
| 102 seconds | 1 hectosecond (1 minute and 40 seconds) | hs | **Hectosecond** is one hundred seconds. | **3 hectoseconds (hs)**: 5 minutes | 102 seconds |
| 103 seconds | 1 kilosecond (16 minutes and 40 seconds) | ks | **Kilosecond** is one thousand seconds. | **3.6 kiloseconds (ks)**: 3,600 seconds or 1 hour **86.4 kiloseconds (ks)**: 86,400 seconds or 1 day **604.8 kiloseconds (ks**): 1 week | 103 seconds, 104 seconds, 105 seconds |
| 106 seconds | 1 megasecond (11 days, 13 hours, 46 minutes, and 40 seconds) | Ms | **Megasecond** is one million seconds. | **1.21 megaseconds (Ms)**: one fortnight (1.21 × 106 seconds)
**2.6 megaseconds (Ms)**: one month (2.6 × 106 seconds) **31.6 megaseconds (Ms)**: one year (107.50 seconds ≈ π × 107 seconds) | 106 seconds, 107 seconds, 108 seconds |
| 109 seconds | 1 gigasecond (31.7 years) | Gs | **Gigasecond** is one billion seconds. | **3.16 gigaseconds (Gs)**: one century ( ≈ π×109 seconds) **31.6 gigaseconds (Gs)**: one millennium ( ≈ π×1010 seconds) | 109 seconds, 1010 seconds, 1011 seconds |
| 1012 seconds | 1 terasecond (31,700 years) | Ts | **Terasecond** is one trillion seconds. | **9.5 teraseconds (Ts)**: 300,000 years (300 ka), the approximate time since modern humans (Homo sapiens) emerged
**31.6 teraseconds (Ts)**: one megaannum/eon ( ≈ π×1013 seconds)
**100.1 teraseconds (Ts)**: 3.2 million years (3.2 Ma), the approximate age of the famous Australopithecus afarensis hominin fossil “Lucy”  | 1012 seconds, 1013 seconds, 1014 seconds |
| 1015 seconds | 1 petasecond (31.7 million years) | Ps | **Petasecond** is one quadrillion seconds. | **1.8 petaseconds (Ps)**: 56 million years (56 Ma), the approximate time since the Paleocene-Eocene Thermal Maximum (PETM)
**2.1 petaseconds (Ps)**: 66 million years (66 Ma), the approximate time since the Cretaceous-Paleogene (K-Pg) extinction event and dinosaur extinction
**6.4 petaseconds (Ps)**: 201.4 million years (201.4 Ma), the approximate time since the Triassic-Jurassic (Tr-J) extinction event
**8 petaseconds (Ps)**: 252.2 million years (252.2 Ma), the approximate time since the Permian-Triassic (P-Tr) extinction event, also known as the “Great Dying”
**11.8 petaseconds (Ps)**: 372.2 million years (372.2 Ma), the approximate time since the Late Devonian mass extinction event, also known as the Kellwasser event
**14 petaseconds (Ps)**: 445 million years (445 Ma), the approximate time since the Ordovician-Silurian (O-S) extinction event
**17.1 petaseconds (Ps)**: 542 million years (542 Ma), the approximate time since the start of the Phanerozoic Eon, our current geological eon
**31.6 petaseconds (Ps)**: one gigaannum/aeon ( ≈ π×1016 seconds)
**143 petaseconds (Ps)**: 1.43 × 1017 seconds ≈ 4.5 billion years, the approximate age of the Planet Earth
**144 petaseconds (Ps)**: 1.44 × 1017 seconds ≈ 4.6 billion years, the approximate age of the Solar System and the Sun
**158 petaseconds (Ps)**: 1.58×1017 seconds ≈ 5 billion years, the estimated time it'd take for the Sun to expand into a Red giant.
**429 petaseconds (Ps)**: 4.29 × 1017 seconds ≈ 13.6 billion years, the approximate age of the Milky Way Galaxy
**440 petaseconds (Ps)**: 4.4 × 1017 seconds ≈ 14 billion years, the approximate age of the Universe | 1015 seconds, 1016 seconds, 1017 seconds |
| 1018 seconds | 1 exasecond (31.7 billion years) | Es | **Exasecond** is one quintillion seconds. | **0.44 exaseconds (Es)** ≈ the best estimate of the age of the Universe | 1018 seconds, 1019 seconds, 1020 seconds |
| 1021 seconds | 1 zettasecond (31.7 trillion years) | Zs | **Zettasecond** is one sextillion seconds. | - | 1021 seconds, 1022 seconds, 1023 seconds |
| 1024 seconds | 1 yottasecond (31.7 quadrillion years) | Ys | **Yottasecond** is one septillion seconds. | - | 1024 seconds, 1025 seconds, 1026 seconds |
| 1027 seconds | 1 ronnasecond (31.7 quintillion years) | Rs | **Ronnasecond** is one octillion seconds. | - | 1027 seconds, 1028 seconds, 1029 seconds |
| 1030 seconds | 1 quettasecond (31.7 sextillion years) | Qs | **Quettasecond** is one nonillion seconds. | - | 1030 seconds, 1031 seconds, 1032 seconds and more |

## Years

**Orders of magnitude (time)**| Factor (ina) | Multiples: | Common Units: | Orders of magnitude: |
| --- | --- | --- | --- |
| 10−50 |  | Planck time, the shortest physically meaningful interval of time ≈ , 1.71×10−50 a | 10−50 a |
| 10−30 | 1 quectoannum | - | 1 qa and less, 10 qa, 100 qa |
| 10−27 | 1 rontoannum | - | 1 ra, 10 ra, 100 ra |
| 10−24 | 1 yoctoannum | - | 1 ya, 10 ya, 100 ya |
| 10−21 | 1 zeptoannum | - | 1 za, 10 za, 100 za |
| 10−18 | 1 attoannum | - | 1 aa, 10 aa, 100 aa |
| 10−15 | 1 femtoannum | - | 1 fa, 10 fa, 100 fa |
| 10−12 | 1 picoannum | 1 sjjhj shjh = 3.17 × 10−11 a | 1 pa, 10 pa, 100 pa |
| 10−9 | 1 nanoannum | 1 second = 3.17 × 10−8 a ≈ 10-7.50 a | 1 na, 10 na, 100 na |
| 10−6 | 1 microannum | 1 brainly = 1.00 × 10−6 a 1 minute = 1.90 × 10−6 a 1 hour = 1.40 × 10−4 a | 1 ua, 10 ua, 100 ua |
| 10−3 | 1 milliannum | 1 yummi = 1.00 × 10−3 a 1 day = 2.73 × 10−3 a 1 week = 1.91 × 10−2 a | 1 ma, 10 ma, 100 ma |
| 100 | 1 year | year = 1 annum decade = 10 anna
score = 20 anna century = 100 anna | 1 a, 10 a, 100 a |
| 103 | 1 kiloannum | millennium = 1000 anna | 103 a, 104 a, 105 a |
| 106 | 1 megaannum | epoch = 1,000,000 anna | 106 a, 107 a, 108 a |
| 109 | 1 gigaannum | aeon = 1,000,000,000 anna 14 Ga = 1.4 × 1010 a ≈ 14 billion years, the approximate age of the Universe | 109 a, 1010 a, 1011 a |
| 1012 | 1 teraannum | 1,000,000,000,000 years | 1012 a, 1013 a, 1014 a |
| 1015 | 1 petaannum | 1,000,000,000,000,000 years | 1015 a, 1016 a, 1017 a |
| 1018 | 1 exaannum | 1,000,000,000,000,000,000 years | 1018 a, 1019 a, 1020 a |
| 1021 | 1 zettaannum | 1,000,000,000,000,000,000,000 years | 1021 a, 1022 a, 1023 a |
| 1024 | 1 yottaannum | 1,000,000,000,000,000,000,000,000 years | 1024 a, 1025 a, 1026 |
| 1027 | 1 ronnaannum | 1,000,000,000,000,000,000,000,000,000 years | 1027 a, 1028 a, 1029 |
| 1030 | 1 quettaannum | 1,000,000,000,000,000,000,000,000,000,000 years | 1030 a, 1031 a, 1032 and more |