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

[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.[1]	The shortest or earliest meaningful interval of time that theoretical physics can describe and consequently the youngest the known universe can be measured, after the Big Bang went off. ≈ 5.4 × 10−44 s.	10−44 s
10−24	1 yoctosecond	ys[2]	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.[citation needed] 1 ys: time for top quark decay.[citation needed] 1 ys: time taken for a quark to emit a gluon. 91 ys: half-life of lithium-4.[citation needed]	1 ys and less, 10 ys, 100 ys
10−21	1 zeptosecond	zs	Zeptosecond, (zepto + second), is one trillionth of one billionth 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	1 zs, 10 zs, 100 zs
10−18	1 attosecond	as		100 attoseconds: shortest measured period of time.[3][4]	1 as, 10 as, 100 as
10−15	1 femtosecond	fs		cycle time for 390 nanometre light, transition from visible light to ultraviolet	1 fs, 10 fs, 100 fs
10−12	1 picosecond	ps		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		1 ns: Time to execute one machine cycle by an Intel Pentium 4 1GHz 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		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		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
10−2	1 centisecond	cs
100	1 second	s		1 s: "One Mississippi" said aloud 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.[5] 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		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 (32 years)	Gs		century = 3.16 Gs ≈ π × 109 s millennium = 31.6 Gs ≈ π × 1010 s	109 s, 1010 s, 1011 s
1012	1 terasecond (32 000 years)	Ts		eon = 31.6 Ts ≈ π × 1013 s	1012 s, 1013 s, 1014 s
1015	1 petasecond (32 million years)	Ps		aeon = 31.6 Ps ≈ π × 1016 s 430 Ps = 4.3 × 1017 s ≈ 13.7 billion years, the approximate age of the Universe	1015 s, 1016 s, 1017 s
1018	1 exasecond (32 billion years)	Es		0.43 Es ≈ the approximate age of the Universe	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

v • d • e Orders of magnitude (time), by powers of seconds Negative powers 10−44 s | ... | 10−25 s ... 10−19 s | 10−18 s ... 10−16 s | 10−15 s ... 10−13 s | 10−12 s | 10−11 s | 10−10 s | 10−9 s | 10−8 s | 10−7 s | 10−6 s | 10−5 s | 10−4 s | 10−3 s | 10−2 s | 10−1 s Positive powers 1 s | 10 s | 102 s | 103 s | 104 s | 105 s | 106 s | 107 s | 108 s | 109 s | 1010 s | 1011 s | 1012 s | 1013 s |1014 s | 1015 s | 1016 s | 1017 s | 1017 s and more

[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 (= 365.25 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] External links

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

[edit] Footnotes

1. ^ Wikipedia contributors. Planck time. Wikipedia, The Free Encyclopedia. December 7, 2007, 05:55 UTC. Available at: http://en.wikipedia.org/w/index.php?title=Planck_time&oldid=176315682. Accessed December 19, 2007.
2. ^ 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
3. ^ "Shortest time interval measured". BBC News. 25 February 2004. http://news.bbc.co.uk/2/hi/science/nature/3486160.stm. 
4. ^ "Fastest view of molecular motion". BBC News. 4 March 2006. http://news.bbc.co.uk/1/hi/sci/tech/4766842.stm. 
5. ^ http://tycho.usno.navy.mil/leapsec.html

Orders of magnitude
area	angular velocity	charge	currency	data	density	energy
frequency	length	magnetic field	mass	numbers	power	pressure
specific energy density	specific heat capacity	speed	temperature	time	volume
Conversion of units
physical unit	SI	SI base unit	SI derived unit	SI prefix	Planck units

v • d • e Time measurement and standards Major subjects Time · Chronometry · Orders of magnitude · Units of time · Metrology Time Portal International standards UTC · UT · TAI · ISO 31-1 · Second · DUT1 · Leap second · IERS Terrestrial Time · Geocentric Coordinate Time · Barycentric Coordinate Time Civil time · Minute · Hour · 12-hour clock · 24-hour clock · ISO 8601 International Date Line · Solar time · Time zone · Daylight saving time · Time offset Obsolete standards Ephemeris time · Barycentric Dynamical Time · Greenwich Mean Time · Prime Meridian Time in physics Spacetime · Chronon · Cosmological decade · Planck epoch · Planck time · T-symmetry Theory of relativity · Time dilation · Gravitational time dilation · Coordinate time · Proper time Time domain · Continuous time · Discrete time · Absolute time and space Horology Clock · Astrarium · Atomic clock · Hourglass · Marine chronometer · Radio clock · Sundial · Watch · Water clock History of timekeeping devices · Equation of time · Complication Calendar Day · Week · Month · Year · Decade · Century · Millennium Astronomical · Julian · Gregorian · Islamic · Lunisolar · Solar · Lunar · Epact · Intercalation · Leap year Tropical year · Equinox · Solstice · Seven-day week · Week-day names · Calculating the day of the week · Dominical letter Archaeology & geology International Commission on Stratigraphy · Geologic Time · Archaeological dating Astronomical chronology Nuclear time scale · Precession · Sidereal time · Galactic year Unusual units Fortnight · Jiffy · Lustrum · Saeculum · Shake · Tide Related topics Chronology · Duration · System time · Metric time · Mental chronometry · Time value of money · Timekeeper

v • d • e Orders of magnitude (time), by powers of seconds Negative powers 10−44 s | ... | 10−25 s ... 10−19 s | 10−18 s ... 10−16 s | 10−15 s ... 10−13 s | 10−12 s | 10−11 s | 10−10 s | 10−9 s | 10−8 s | 10−7 s | 10−6 s | 10−5 s | 10−4 s | 10−3 s | 10−2 s | 10−1 s Positive powers 1 s | 10 s | 102 s | 103 s | 104 s | 105 s | 106 s | 107 s | 108 s | 109 s | 1010 s | 1011 s | 1012 s | 1013 s |1014 s | 1015 s | 1016 s | 1017 s | 1017 s and more