Contents 1 Seconds 2 See also 3 Years 4 See also 5 Footnotes 6 External links

[edit] Seconds

Orders of magnitude (time)

Factor (s)	Multiple	Symbol	Definition	Comparative examples & common units	Orders of magnitude
10−44		tP	Planck time is the unit of time of the natural units system known as Planck units.	Planck time = .	10−44 s
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.[2][3][a] 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 sixtillionth of one second (short scale).	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[4]	1 zs, 10 zs, 100 zs
10−18	1 attosecond	as	One quintillionth of one second	12 attoseconds: shortest measured period of time.[5]	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 50–80 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.[6] 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)[7] 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			1012 s, 1013 s, 1014 s
1015	1 petasecond (32 million years)	Ps		7.1–7.9 Ps: 1 galactic year[8] 143 Ps: the age of the Earth[9][10][11] 144 Ps: the approximate age of the Solar system[12] and the Sun.[13] 430 Ps: the approximate age of the Universe	1015 s, 1016 s, 1017 s
1018	1 exasecond (32 billion years)	Es			1018 s, 1019 s, 1020 s
1021	1 zettasecond (32 trillion years)	Zs			1021 s, 1022 s, 1023 s
1024	1 yottasecond (32 quadrillion years)	Ys			1024 s, 1025 s, 1026 s and more

[edit] 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
• Graphical timeline of the Stelliferous Era
• 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.
• Timeline of the Big Bang
• Graphical timeline of the Big Bang
• 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.

[edit] 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 log₁₀ year to log₁₀ second is approximately log₁₀ year + 7.50. Example conversion; 1 year = 10⁰ year = 10^{0 + 7.50} seconds = 10^{0.50 + 7}s = 3.16 * 10⁷s.

[edit] 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

[edit] Footnotes

1. ^ The American Heritage Dictionary of the English Language: Fourth Edition. 2000. Available at: http://www.bartleby.com/61/21/Y0022100.html. Accessed December 19, 2007. note: abbr. ys or ysec
2. ^ C. Amsler et al. (2009): Particle listings – W boson
3. ^ C. Amsler et al. (2009): Particle listings – Z boson
4. ^ esciencenews (2010)
5. ^ "12 attoseconds is the world record for shortest controllable time". http://www.physorg.com/news192909576.html. 
6. ^ http://tycho.usno.navy.mil/leapsec.html
7. ^ CIA - The World Factbook -- Rank Order - Life expectancy at birth
8. ^ Leong, Stacy (2002). "Period of the Sun's Orbit around the Galaxy (Cosmic Year)". The Physics Factbook. http://hypertextbook.com/facts/2002/StacyLeong.shtml. 
9. ^ "Age of the Earth". U.S. Geological Survey. 1997. http://pubs.usgs.gov/gip/geotime/age.html. Retrieved 2006-01-10. 
10. ^ Dalrymple, G. Brent (2001). "The age of the Earth in the twentieth century: a problem (mostly) solved". Special Publications, Geological Society of London 190 (1): 205–221. doi:10.1144/GSL.SP.2001.190.01.14. 
11. ^ Manhesa, Gérard; Allègrea, Claude J.; Dupréa, Bernard; and Hamelin, Bruno (1980). "Lead isotope study of basic-ultrabasic layered complexes: Speculations about the age of the earth and primitive mantle characteristics". Earth and Planetary Science Letters, Elsevier B.V. 47 (3): 370–382. doi:10.1016/0012-821X(80)90024-2. 
12. ^ Bouvier, Audrey and Meenakshi Wadhwa, “The age of the solar system redefined by the oldest Pb-Pb age of a meteoritic inclusion”. Nature Geoscience, Nature Publishing Group, a division of Macmillan Publishers Limited. Published online 2010-08-22, retrieved 2010-08-26, doi: 10.1038/NGEO941.
13. ^ Bonanno, A.; Schlattl, H.; Paternò, L. (2008). "The age of the Sun and the relativistic corrections in the EOS". Astronomy and Astrophysics 390 (3): 1115–1118. arXiv:astro-ph/0204331. Bibcode 2002A&A...390.1115B. doi:10.1051/0004-6361:20020749. 

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

[edit] External links

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

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