Orders of magnitude (time)

Seconds

Orders of magnitude (Time)

Factor (s)	Multiple	Symbol	Definition	Comparative examples & common units	Orders of magnitude
10−44				5.4×10-20 ys = 5.4×10-44 s: One Planck time tP = $\sqrt{\hbar G/c^5}$ ≈ 5.4×10-44 s, the time required for light to travel one Planck length, is the briefest physically meaningful span of time. It is the unit of time in the natural units system known as Planck units.	10−20 ys, 10−19 ys (10−44 s, 10−43 s)
10−24	1 yoctosecond	ys	Yoctosecond, (yocto- + second), is one septillionth (short scale) of a second.	0.3 ys: mean life of the W and Z bosons. 0.5 ys: time for top quark decay, according to the Standard Model. 1 ys: time taken for a quark to emit a gluon. 23 ys: half-life of 7H.	1 ys and less, 10 ys, 100 ys
10−21	1 zeptosecond	zs	Zeptosecond, (zepto- + second), is one sextillionth (short scale)of one 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. 500 zs: current resolution of tools used to measure speed of chemical bonding	1 zs, 10 zs, 100 zs
10−18	1 attosecond	as	One quintillionth of one second	12 attoseconds: shortest measured period of time.	1 as, 10 as, 100 as
10−15	1 femtosecond	fs	One quadrillionth of one second	cycle time for 390 nanometre light, transition from visible light to ultraviolet	1 fs, 10 fs, 100 fs
10−12	1 picosecond	ps	One trillionth of one second	1 ps: half-life of a bottom quark 4 ps: Time to execute one machine cycle by an IBM Silicon-Germanium transistor	1 ps, 10 ps, 100 ps
10−9	1 nanosecond	ns	One billionth of one second	1 ns: Time to execute one machine cycle by a 1 GHz microprocessor 1 ns: Light travels 12 inches (30 cm)	1 ns, 10 ns, 100 ns
10−6	1 microsecond	µs	One millionth of one 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 a 1960s minicomputer	1 µs, 10 µs, 100 µs
10−3	1 millisecond	ms	One thousandth of one second	4–8 ms: typical seek time for a computer hard disk 100–400 ms: Blink of an eye 150–300 ms: Human reflex response to visual stimuli	1 ms, 10 ms, 100 ms
100	1 second	s		1 s: 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom. 60 s: 1 minute	1 s, 10 s, 100 s
103	1 kilosecond (16.7 minutes)	ks		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		2.6 Ms: approximately 1 month 31.6 Ms: approximately 1 year ≈ 107.50 s	106 s, 107 s, 108 s
109	1 gigasecond (32 years)	Gs		2.1 Gs: average human life expectancy at birth (2011 estimate) 3.16 Gs: approximately 1 century 31.6 Gs: approximately 1 millennium	109 s, 1010 s, 1011 s
1012	1 terasecond (32 000 years)	Ts		6 Ts: time since the appearance of Homo sapiens (approximately)	1012 s, 1013 s, 1014 s
1015	1 petasecond (32 million years)	Ps		7.1–7.9 Ps: 1 galactic year (225-250 million years) 143 Ps: the age of the Earth 144 Ps: the approximate age of the Solar system and the Sun. 430 Ps: the approximate age of the Universe	1015 s, 1016 s, 1017 s
1018	1 exasecond (32 billion years)	Es		312 Es: Estimated lifespan of a 0.1 solar mass red dwarf star.	1018 s, 1019 s, 1020 s
1021	1 zettasecond (32 trillion years)	Zs		3 Zs: Estimated duration of Stelliferous Era. 9.8 Zs:the lifetime of Brahma in Hindu mythology	1021 s, 1022 s, 1023 s
1024	1 yottasecond (32 quadrillion years)	Ys		6.616×1050 Ys: Time required for a 1 solar mass black hole to evaporate completely due to Hawking radiation, if nothing more falls in.	1024 s, 1025 s, 1026 s and more

See also

• Heat Death
• Second law of thermodynamics
• Big Rip
• Big Crunch
• Big Bounce
• Big Bang
• Cyclic model
• Dyson's eternal intelligence
• Final anthropic principle
• Ultimate fate of the Universe
• Timeline of the Big Bang
• Graphical timeline of the Big Bang
• Graphical timeline from Big Bang to Heat Death. This timeline uses the loglog scale for comparison with the graphical timeline included in this article.
• Graphical timeline of our universe. This timeline uses the more intuitive linear time, for comparison with this article.
• Graphical timeline of the Stelliferous Era
• The Last Question, a short story by Isaac Asimov which considers the inevitable outcome of heat death in the universe and how it may be reversed.
• Orders of magnitude (frequency)

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 annum	1 average year = 1 annum (= 365.24219 SI days) 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	---	1012 a, 1013 a, 1014 a
1015	1 petaannum	---	1015 a, 1016 a, 1017 a
1018	1 exaannum	--	1018 a, 1019 a, 1020 a
1021	1 zettaannum	--	1021 a, 1022 a, 1023 a
1024	1 yottaannum	--	1024 a, 1025 a, 1026 and more

The pages linked in the right-hand column contain lists of times that are of the same order of magnitude (power of ten). Rows in the table represent increasing powers of a thousand (3 orders of magnitude).

Conversion from year to second is year × 31 557 600 using the Julian year. Conversion from log ₁₀ year to log ₁₀ second is approximately log ₁₀ year + 7.50. Example conversion; 1 year = 10⁰ year = 10^{0 + 7.50} seconds = 10^{0.50 + 7}s = 3.16 * 10⁷s.

See also

• Annum
• Geologic timescale
• Human timescales
• Logarithmic timeline
• Natural history
• Physical unit

• Planck units
• Second
• Temporal resolution
• Timeline of evolution
• Timeline of the Big Bang

Footnotes

^[a] ^ PDG reports the resonance width (Γ). Here the conversion τ = ^ħ⁄_Γ is given instead.

External links

• Exploring Time from Planck time to the lifespan of the universe