# Orders of magnitude (time)

An order of magnitude describes the link between two 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, 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 s, a hour is 60 min, a day is 24 hour, a week is 7 days, a month is 4 weeks, a year is 12 months, a millennium is 1000 years, etc...

## secs

Orders of magnitude in seconds (time)
Factor (s) Multiple Symbol Definition Comparative examples & common units Orders of magnitude
10⁻⁴³ 1 Planck Time p Planck Time is the time required for light to travel a distance of 1 Planck length in vacuum.
10−30 1 quectosecond qs Quectosecond, (quecto + second), is one nonillionth (in the short scale) of a second.
10−27 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
10−24 1 yoctosecond ys[1] 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.[source?]
1 ys: time for top quark decay.[source?]
1 ys: time taken for a quark to emit a gluon.
91 ys: half-life of lithium-4.[2]
1 ys and less, 10 ys, 100 ys
10−21 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.
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 1 attosecond [as] Attosecond is one quintillionth of a second. 100 attoseconds: shortest measured period of time.[3][4] 1 as, 10 as, 100 as
10−15 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 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 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 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 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 1 centisecond cs Centisecond is one hundredth of a second.
10−1 1 decisecond ds Decisecond is one tenth of a second.
100 1 second s 1 s: "One Mississippi" said aloud
60 s: 1 minute
1 s, 10 s, 100 s
101 1 decasecond
(10 seconds)
das Decasecond is ten seconds.
102 1 hectosecond
(1.67 minutes)
hs Hectosecond is one hundred seconds.
103 1 kilosecond
(16.7 minutes)
ks Kilosecond is one thousand seconds. 3.6 ks: 3600 s or 1 hour
86.4 ks: 86 400 s or 1 day
604.8 ks: 1 week
103 s, 104 s, 105 s
106 1 megasecond
(11.6 days)
Ms Megasecond is one million seconds. month = 2.6 x 106 s
year = 31.6 Ms = 107.50 s ≈ π x 107 s
106 s, 107 s, 108 s
109 1 gigasecond
(31.7 years)
Gs Gigasecond is one billion seconds. century = 3.16 Gs ≈ π×109 s
millennium = 31.6 Gs ≈ π×1010 s
109 s, 1010 s, 1011 s
1012 1 terasecond
(31 700 years)
Ts Terasecond is one trillion seconds. eon = 31.6 Ts ≈ π×1013 s 1012 s, 1013 s, 1014 s
1015 1 petasecond
(31.7 million years)
Ps Petasecond is one quadrillion seconds. aeon = 31.6 Ps ≈ π×1016 s
435 Ps = 4.35×1017 s ≈ 13.8 billion years, the approximate age of the Universe
1015 s, 1016 s, 1017 s
1018 1 exasecond
(31.7 billion years)
Es Exasecond is one quintillion seconds. 0.43 Es ≈ the best estimate of the age of the Universe 1018 s, 1019 s, 1020 s
1021 1 zettasecond
(31.7 trillion years)
Zs Zettasecond is one sextillion seconds. 1021 s, 1022 s, 1023 s
1024 1 yottasecond
Ys Yottasecond is one septillion seconds. 1024 s, 1025 s, 1026 s and more
1027 1 ronnasecond
(31.7 quintillion years)
Rs Ronnasecond is one octillion seconds.
1030 1 quettasecond
(31.7 sextillion years)
Qs Quettasecond is one nonillion seconds.

## Years

Orders of magnitude (time)
Factor (a) Multiple common units orders of magnitude
10−50 Planck time, the shortest physically meaningful interval of time ≈ 1.71×10−50 a 10−50 a
10−24 1 yoctoannum -- 1 ya and less, 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 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 minute = 1.90 × 10−6 a
1 hour = 1.40 × 10−4 a
1 ua, 10 ua, 100 ua
10−3 1 milliannum 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
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
13.7 Ga = 1.37×1010 a ≈ 13.7 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 and more

## References

1. The American Heritage Dictionary of the English Language: Fourth Edition. 2000. Available at: http://www.bartleby.com/61/21/Y0022100.html Archived 2008-03-10 at the Wayback Machine. Accessed December 19, 2007. note: abbr. ys or ysec
2. "Isotope data for lithium-4 in the Periodic Table". periodictable.com. Retrieved 2022-10-01.
3. "Shortest time interval measured". BBC News. 25 February 2004.
4. "Fastest view of molecular motion". BBC News. 4 March 2006.