Exa-




This article is about the SI prefix. For other uses, see Exa (disambiguation).





Exa is a decimal unit prefix in the metric system denoting 1018 or 1000000000000000000. It was added as an SI prefix to the International System of Units (SI) in 1975,[1] and has the unit symbol E.


Exa comes from the Ancient Greek ἕξ héx, used as a prefix ἑξά- hexá-, meaning six (like hexa-), because it is equal to 10006.


Examples:



  • The total storage needed by Google Mail as of April 2012, ignoring backups and compression, is more than an exabyte (10,240 megabytes of storage per user multiplied by an estimated 260 million users).

  • 1 EeV = 1018electronvolts = 0.1602 joule


  • United States electric energy consumption is about 15 exajoule per year.

  • 1 exasecond is approximately 32 billion years


  • 1 exametre is approximately 110 light years

  • 0.43 Es ≈ the approximate age of the Universe

  • 1.6 Em—172 ± 12.5 light years—Diameter of Omega Centauri (one of the largest known globular clusters, perhaps containing over a million stars)[2][3]

  • 23.6 exahashes/s is the calculation rate of the Bitcoin network ≈ 23600000000000000000 hashes per second (Mar 2018)[4]







SI prefixes

  • v

  • t

  • e




























































































































































































































Prefix
 Base 1000
 Base 10
Decimal
 English word
 Adoption[nb 1]
Name
 Symbol
Short scale
Long scale

yotta
 Y
  10008
  1024
1000000000000000000000000
  septillion
  quadrillion
 1991

zetta
 Z
  10007
  1021
1000000000000000000000
  sextillion
  trilliard
 1991

exa
 E
  10006
  1018
1000000000000000000
  quintillion
  trillion
 1975

peta
 P
  10005
  1015
1000000000000000
  quadrillion
  billiard
 1975

tera
 T
  10004
  1012
1000000000000
  trillion
  billion
 1960

giga
 G
  10003
  109
1000000000
  billion
  milliard
 1960

mega
 M
  10002
  106
1000000
  million
 1873

kilo
 k
  10001
  103
1000
  thousand
 1795

hecto
 h
  10002/3
  102
 100
  hundred
 1795

deca
 da
  10001/3
  101
 10
  ten
 1795

 10000
  100
 1
  one
 –

deci
 d
  1000−1/3
  10−1
 0.1
  tenth
 1795

centi
 c
  1000−2/3 
  10−2
 0.01
  hundredth
 1795

milli
 m
  1000−1
  10−3
 0.001
  thousandth
 1795

micro
 µ
  1000−2
  10−6
0.000001
  millionth
 1873

nano
 n
  1000−3
  10−9
0.000000001
  billionth
  milliardth
 1960

pico
 p
  1000−4
  10−12
0.000000000001
  trillionth
  billionth
 1960

femto
 f
  1000−5
  10−15
0.000000000000001
  quadrillionth
  billiardth
 1964

atto
 a
  1000−6
  10−18
0.000000000000000001
  quintillionth
  trillionth
 1964

zepto
 z
  1000−7
  10−21
0.000000000000000000001
  sextillionth
  trilliardth
 1991

yocto
 y
  1000−8
  10−24 
0.000000000000000000000001
  septillionth
  quadrillionth
 1991





  1. ^ Prefixes adopted before 1960 already existed before SI. 1873 was the introduction of the CGS system.



See also



  • Exametre

  • Exabyte

  • Exasecond

  • Orders of magnitude (numbers)

  • Metric prefix

  • Binary prefix



References





  1. ^ "Resolution 10 of the 15th meeting of the CGPM (1975)". International Bureau of Weights and Measures. Retrieved 2012-04-18..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}


  2. ^ distance × sin( diameter_angle ), using distance of 5 kpc (15.8 ± 1.1 kly) and angle 36.3', = 172 ± 12.5 ly.


  3. ^ van de Ven, G.; van den Bosch, R. C. E.; Verolme, E. K.; de Zeeuw, P. T. (January II 2006). "The dynamical distance and intrinsic structure of the globular cluster ω Centauri". Astronomy and Astrophysics. 445 (2): 513–543. arXiv:astro-ph/0509228. Bibcode:2006A&A...445..513V. doi:10.1051/0004-6361:20053061. best-fit dynamical distance D=4.8±0.3 kpc ... consistent with the canonical value 5.0±0.2 kpc obtained by photometric methods Check date values in: |date= (help)CS1 maint: Multiple names: authors list (link)


  4. ^ "Bitcoinity.org". data.bitcoinity.org. Retrieved 2017-12-06.




  • International Bureau of Weights and Measures (2006), The International System of Units (SI) (PDF) (8th ed.), ISBN 92-822-2213-6, archived (PDF) from the original on 2017-08-14


External links







  • BIPM website

  • Exa Corporation

  • Exa Proxy Test




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