Orders of magnitude (mass)

To help compare different orders of magnitude, the following list describes various mass levels between 10−36kg and 1060 kg.

Contents

Units of mass

SI multiples for gram (g)
Submultiples Multiples
Value Symbol Name Value Symbol Name
10−1 g dg decigram 101 g dag decagram
10−2 g cg centigram 102 g hg hectogram
10−3 g mg milligram 103 g kg kilogram
10−6 g µg microgram (mcg) 106 g Mg megagram (tonne)
10−9 g ng nanogram 109 g Gg gigagram
10−12 g pg picogram 1012 g Tg teragram
10−15 g fg femtogram 1015 g Pg petagram
10−18 g ag attogram 1018 g Eg exagram
10−21 g zg zeptogram 1021 g Zg zettagram
10−24 g yg yoctogram 1024 g Yg yottagram
Common prefixes are in bold face.[1]

The table below is based on the kilogram (kg), the base unit of mass in the International System of Units (SI). The kilogram is the only standard unit to include an SI prefix (kilo-) as part of its name. The gram (10−3 kg) is an SI derived unit of mass. However, the names of all SI mass units are based on gram, rather than on kilogram; thus 103 kg is a megagram (106 g), not a "kilokilogram".

The tonne (t) is a SI-compatible unit of mass equal to a megagram, or 103 kg. The unit is in common use for masses above about 103 kg and is often used with SI prefixes.

Other units

Other units of mass are in use. Historical units include the stone, the pound, the carat and the grain.

For subatomic particles, physicists use the mass equivalent to the energy represented by an electron Volt (eV). at the atomic level, chemists use the mass of one-twelfth of a carbon-12 atom (the Dalton). Astronomers use the mass of the sun (\begin{smallmatrix}M_\odot\end{smallmatrix}).

below 10−24 kg

Unlike other physical quantities, mass-energy does not have an a priori expected minimal quantity, as is the case with time or length, or an observed basic quantum as in the case of electric charge. Planck's law allows for the existence of photons with arbitrarily low energies. Consequently, there can only ever be an experimental lower bound on the mass of a supposedly massless particle; in the case of the photon, this confirmed lower bound is of the order of 3×10−27 eV = 10-62 kg.

Factor (kg) Value Item
10−40 4.2×10−40 kg Mass equivalent of the energy of a photon at the peak of the spectrum of the cosmic microwave background radiation (0.235 meV/c2)
10−36 1.8×10−36 kg One eV/c2, the mass equivalent of one electronvolt[2]
3.6×10−36 kg Electron neutrino, upper limit on mass (2 eV/c2)[3]
10−31 9.11×10−31 kg Electron (511 keV/c2), the lightest elementary particle with a measured nonzero rest mass[4]
10−28 1.9×10−28 kg Muon (106 MeV/c2)[5]
10−27
yoctogram (yg)
1.661×10−27 kg Atomic mass unit (u) or dalton (Da)
1.673×10−27 kg Proton (938.3 MeV/c2)[6][7]
1.674×10−27 kg Hydrogen atom, the lightest atom
1.675×10−27 kg Neutron (939.6 MeV/c2)[8][9]
10−26 1.2×10−26 kg Lithium atom (6.941 u)
3.0×10−26 kg Water molecule (18.015 u)
8.0×10−26 kg Titanium atom (47.867 u)
10−25 1.6×10−25 kg Z boson (91.2 GeV/c2)[10]
1.8×10−25 kg Silver atom (107.8682 u)
3.1×10−25 kg Top quark (173 GeV/c2)[11], the heaviest known elementary particle
3.2×10−25 kg Caffeine molecule (194 u)
3.5×10−25 kg Lead-208 atom, the heaviest stable isotope known

10-24 to 10-19 kg

Factor (kg) Value Item
10−24
zeptogram (zg)
1.2×10−24 kg Buckyball molecule (720 u)
10−23 1.4×10−23 kg Ubiquitin, a small protein (8.6 kDa)[12]
5.5×10−23 kg A typical protein (median size of roughly 300 amino acids ~= 33 kDa)[13]
10−22 1.1×10−22 kg Haemoglobin A molecule in blood (64.5 kDa)[14]
10−21
attogram (ag)
1.65×10−21 kg Double-stranded DNA molecule consisting of 1,578 base pairs (995,000 daltons)[15]
4.3×10−21 kg Prokaryotic ribosome (2.6 MDa)[16]
7.1×10−21 kg Eukaryotic ribosome (4.3 MDa)[16]
7.6×10−21 kg Brome mosaic virus, a small virus (4.6 MDa)[17]
10−20 3×10−20 kg Synaptic vesicle in rats (16.1 ± 3.8 MDa)[18]
6.8×10−20 kg Tobacco mosaic virus (41 MDa)[19]
10−19 1.1×10−19 kg Nuclear pore complex in yeast (66 MDa)[20]
2.5×10−19 kg Human adenovirus (150 MDa)[21]

10-18 to 10-13 kg

Factor (kg) Value Item
10−18
femtogram (fg)
1×10−18 kg HIV-1 virus[22][23]
4.7×10−18 kg DNA sequence of length 4.6 Mbp, the length of the E. coli genome[24]
10−17 ~1×10−17 kg Vaccinia virus, a large virus[25]
1.1×10−17 kg Mass equivalent of 1 joule[26]
10−16 3×10−16 kg Prochlorococcus cyanobacteria, the smallest (and possibly most plentiful)[27] photosynthetic organism on Earth[28][29]
10−15
picogram (pg)
1×10−15 kg E. coli bacterium (wet weight)[30]
6×10−15 kg DNA in a typical diploid human cell (approximate)[31]
10−14 2.2×10−14 kg Human sperm cell[32][29]
6×10−14 kg Yeast cell (quite variable)[33][34]
10−13 1.5×10−13 kg Dunaliella salina, a green algae (dry weight)[35]

10-12 to 10-7 kg

Factor (kg) Value Item
10−12
nanogram (ng)
1×10−12 kg Average human cell (1 nanogram)
2-3×10−12 kg HeLa human cell[36][37]
10−11    
10−10 3.5×10−10 kg Small grain of sand (0.063 mm diameter, 350 nanograms)
10−9
microgram (µg)
3.6×10−9 kg Human ovum[38][29]
2.4×10−9 kg US RDA for vitamin B12 for adults[39]
10−8 1.5×10−8 kg US RDA for vitamin D for adults[40]
~2×10−8 kg Uncertainty in the mass of the International Prototype Kilogram (IPK) (±~20 µg)
2.2×10−8 kg Planck mass[41]
~7×10−8 kg One eyebrow hair (approximate)[42]
10−7 1.5×10−7 kg US RDA for iodine for adults[43]
2-3×10−7 kg Fruit fly (dry weight)[44][45]

10-6 to one kg

Factor (kg) Value Item
10−6
milligram (mg)
2.5×10−6 kg Mosquitoes, common smaller species (about 2.5 milligrams)[46]
10−5
centigram (cg)
1.1×10−5 kg Small granule of quartz (2 mm diameter, 11 milligrams)[47]
2×10−5 kg Adult housefly (Musca domestica, 21.4 milligrams)[48]
10−4
decigram (dg)
0.27–2.0×10−4 kg Range of amounts of caffeine in one cup of coffee (27-200 milligrams)[49]
2×10−4 kg Metric carat (200 milligrams)[50]
10−3
gram (g)
1×10−3 kg One cubic centimeter of water (1 gram)[51]
1×10−3 kg US dollar bill (1 gram)[52]
~1×10−3 kg Two raisins (approximately 1 gram)[53]
8×10−3 kg Coins of one Euro (7.5 grams) and one U.S. dollar (8.1 grams)[54]
10−2
decagram (dag)
2–4×10−2 kg Adult mouse (Mus musculus, 20–40 grams)[55]
1.4×10−2 kg Amount of ethanol defined as one standard drink in the U.S. (13.7 grams)[56]
2.8×10−2 kg Ounce (avoirdupois) (28.35 grams)[50]
4.7×10−2 kg Mass equivalent of the energy that is called 1 megaton of TNT equivalent[50][57]
10−1
hectogram   (hg)
0.1-0.2 kg An orange (100-200 grams)[58]
0.454 kg Pound (avoirdupois) (454 grams)[50]

one kg to 105 kg

Factor (kg) Value Item
1 kg
kilogram (kg)
1 kg One litre (0.001 m3) of water[59]
1-3 kg Smallest breed of dog (Chihuahua)[60]
1-3 kg Typical laptop computer, 2010[61]
2.5-4 kg Newborn human baby[62]
4.0 kg Women's shot put[63]
4–5 kg Housecat
7.26 kg Men's shot put[63]
101 10–30 kg A CRT computer monitor or television set
15–20 kg Medium-sized dog
70 kg Adult human[64]
70 kg Large dog
102 125–180 kg Mature lion, female (125 kg) and male (180 kg)
240-450 kg Grand piano[65][66]
5×102-5×105 kg A teaspoon (5 ml) of white dwarf material (0.5-500 tonnes)[67][68]
400-900 kg Dairy cow[69]
907.2 kg 1 short ton (2000 pounds - U.S.)[50]
103
megagram (Mg)
1000 kg Metric ton/tonne[50]
1000 kg 1 cubic metre of water[59]
1016.05 kg Ton (British) / 1 long ton (2240 pounds - U.S.)[50]
800–1600 kg Typical passenger cars
3000–7000 kg Adult elephant
104 1.1×104 kg Hubble Space Telescope (11 tonnes)[70]
1.2×104 kg Largest elephant on record (12 tonnes)
1.4×104 kg Big Ben (bell) (14 tonnes)[71]
4×104 kg Maximum gross mass (truck + load combined) of a semi-trailer truck in the EU (40-44 tonnes)[72]
6.0×104 kg Largest single-piece meteorite, Hoba West Meteorite (60 tonnes)[73]
7.3×104 kg Largest dinosaur, Argentinosaurus (73 tonnes)[74]
105 1.8×105 kg Largest animal ever, a blue whale (180 tonnes)[75]
4.2×105 kg International Space Station (417 tonnes)[76]
6×105 kg World's heaviest aircraft: Antonov An-225 (maximum take-off mass: 600 tonnes, payload: 250 tonnes)[77]

106 to 1011 kg

Factor (kg) Value Item
106
gigagram (Gg)
1×106 kg Trunk of the giant sequoia tree named General Sherman, largest living tree by trunk volume (1121 tonnes)[78]
2.0×106 kg Launch mass of the Space Shuttle (2041 tonnes)[79]
6×106 kg Largest clonal colony, the quaking aspen named Pando (largest living organism) (6000 tonnes)[80]
7.8×106 kg Virginia-class nuclear submarine (submerged weight)[81]
107 1×107 kg Annual production of Darjeeling tea[82]
5.2×107 kg RMS Titanic when fully loaded (52,000 tonnes)[83]
9.97×107 kg Heaviest train ever: Australia's BHP Iron Ore, 2001 record (99,700 tonnes)[84]
108 6.6×108 kg Largest ship and largest mobile man-made object, Seawise Giant, when fully loaded (660,000 tonnes)[85]
109
teragram (Tg)
4.3×109 kg Amount of matter converted into energy by the Sun each second[86]
6×109 kg Great Pyramid of Giza[87]
1010
6×1010 kg Amount of concrete in the Three Gorges Dam, the world's largest concrete structure[88][89]
1011 ~1×1011 kg The mass of a primordial black hole with an evaporation time equal to the age of the universe[90]
2×1011 kg Amount of water stored in London storage reservoirs (0.2 km3)[91]
4×1011 kg Total mass of the human world population[92][93][94]
5×1011 kg Total biomass of Antarctic krill, probably the most plentiful animal species on the planet[95]

1012 to 1017 kg

Factor (kg) Value Item
1012
petagram (Pg)
0.8-2.1×1012 kg Global biomass of fish[96]
4×1012 kg World crude oil production in 2009 (3,843 Mt)[97]
5.5×1012 kg A teaspoon (5 ml) of neutron star material (5000 million tonnes)[98]
1013 1-100×1013 kg A 1km-5km tall mountain (very approximate)[99]
1014 1.05×1014 kg Global net primary production – the total mass of carbon fixed in organic compounds by photosynthesis each year on Earth[100]
7.2×1014 kg Total carbon stored in Earth's atmosphere[101]
1015
exagram (Eg)
2.0×1015 kg Total carbon stored in the terrestrial biosphere[102]
3.5×1015 kg Total carbon stored in coal deposits worldwide[103]
1016 1×1016 kg 951 Gaspra, the first asteroid ever to be closely approached by a spacecraft (rough estimate)[104]
3.8×1016 kg Total carbon stored in the oceans[105]
1017 1.6×1017 kg Prometheus, a shepherd satellite for the inner edge of Saturn's F Ring[106]

1018 to 1023 kg

Factor (kg) Value Item
1018
zettagram (Zg)
5.1×1018 kg Earth's atmosphere[107]
5.6×1018 kg Hyperion, a moon of Saturn[106]
1019 3×1019 kg 3 Juno, one of the larger asteroids in the main asteroid belt[108]
3×1019 kg The rings of Saturn[109]
1020 9.4×1020 kg Ceres, dwarf planet within the asteroid belt[110]
1021
yottagram (Yg)
1.4×1021 kg Earth's oceans[111]
1.5×1021 kg Charon, the largest moon of Pluto[112]
2.9-3.7×1021 kg The asteroid belt[113]
1022 1.3×1022 kg Pluto[114]
2.1×1022 kg Triton, largest moon of Neptune[115]
7.3×1022 kg Earth's Moon[116]
1023 1.3×1023 kg Titan, largest moon of Saturn[117]
1.5×1023 kg Ganymede, largest moon of Jupiter[118]
3.3×1023 kg Mercury[119]
6.4×1023 kg Mars[120]

1024 to 1029 kg

Factor (kg) Value Item
1024 4.9×1024 kg Venus[121]
6.0×1024 kg The Earth[122]
1025 3×1025 kg Oort cloud[123]
8.7×1025 kg Uranus[124]
1026 1.0×1026 kg Neptune[125]
5.7×1026 kg Saturn[126]
1027 1.9×1027 kg Jupiter[127]
1028 2–14×1028 kg Brown dwarf stars (approximate)[128]
1029 3×1029 kg Barnard's Star, a nearby red dwarf star[129]

1030 to 1035 kg

Factor (kg) Value Item
1030 2×1030 kg The Sun[130] (one solar mass or M = 1.989×1030 kg)
2.8×1030 kg Chandrasekhar limit (1.4 M)[131][132]
1031 4×1031 kg Betelgeuse, a red supergiant star (20 M)[133]
1032 2–3×1032 kg Pistol Star, one of the most massive known stars (100[134] to 150[135] M)
6–8×1032 kg Hyades star cluster (300 to 400 M)[136]
1033 1.6×1033 kg Pleiades star cluster (800 M)[137]
1034
1035 ~1035 kg Typical globular cluster in the Milky Way (overall range: 3×103 to 3×106 M)[138]
2×1035 kg Low end of mass range for giant molecular clouds (1×105 to 1×107 M)[139][140]
7.3×1035 kg Jeans mass of a giant molecular cloud at 100K and density 30 atoms per cc;[141]
possible example: Orion Molecular Cloud Complex

1036 to 1041 kg

Factor (kg) Value Item
1036 2.4×1036 kg The Gould Belt of stars, including the Sun (1.2×106 M)[142]
7-8×1036 kg The supermassive black hole at the center of the Milky Way, associated with the radio source Sagittarius A* (3.7±0.2×106 M)[143]
1037    
1038    
1039    
1040 3.6×1040 kg OJ287, the largest measured supermassive black hole (1.8×1010 M)[144]
1041 4×1041 kg Visible mass of the Milky Way galaxy[145]

1042 kg and greater

Factor (kg) Value Item
1042 1.2×1042 kg Milky Way galaxy (5.8×1011 M)[146]
2-3×1042 kg Local Group of galaxies, including the Milky Way (1.29±0.14×1012 M)[146]
1043    
1044    
1045 1-2×1045 kg Local or Virgo Supercluster of galaxies, including the Local Group (1×1015 M)[147]
1046    
1047    
1048    
1049    
1050 3×1050 kg Low end of the range for the estimated mass of the universe[148]
1051    
1052 3×1052 kg Mass of the observable universe
1060 2×1060 kg High end of the range for the estimated mass of the universe[148]

This series on orders of magnitude does not have a range of larger masses

Notes

  1. ^ Criterion: A combined total of at least 250,000 Google hits on both the modern spelling (‑gram) and the traditional British spelling (‑gramme). 
  2. ^ "Conversion from eV to kg". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Convert?exp=0&num=1&From=ev&To=kg&Action=Convert+value+and+show+factor. Retrieved 2011-10-19. 
  3. ^ "The most sensitive analysis on the neutrino mass [...] is compatible with a neutrino mass of zero. Considering its uncertainties this value corresponds to an upper limit on the electron neutrino mass of m<2.2 eV/c2 (95% Confidence Level)" The Mainz Neutrino Mass Experiment
  4. ^ "CODATA Value: electron mass". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Value?me. Retrieved 2011-08-21. 
  5. ^ "CODATA Value: muon mass". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Value?mmu. Retrieved 2011-08-23. 
  6. ^ "CODATA Value: proton mass". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Value?mp. Retrieved 2011-08-23. 
  7. ^ "CODATA Value: proton mass energy equivalent in MeV". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Value?mpc2mev. Retrieved 2011-08-23. 
  8. ^ "CODATA Value: neutron mass". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Value?mn. Retrieved 2011-08-23. 
  9. ^ "CODATA Value: neutron mass energy equivalent in MeV". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Value?mnc2mev. Retrieved 2011-08-23. 
  10. ^ Amsler, C.; Doser, M.; Antonelli, M.; Asner, D.; Babu, K.; Baer, H.; Band, H.; Barnett, R. et al. (2008). "Review of Particle Physics⁎". Physics Letters B 667: 1. doi:10.1016/j.physletb.2008.07.018. http://pdglive.lbl.gov/Rsummary.brl?nodein=S044&fsizein=1.  edit
  11. ^ K. Nakamura et al. (Particle Data Group) (2011). "PDGLive Particle Summary 'Quarks (u, d, s, c, b, t, b', t', Free)'". Particle Data Group. http://pdg.lbl.gov/2011/tables/rpp2011-sum-quarks.pdf. Retrieved 2011-08-08. 
  12. ^ "Ubiquitin". Channel Proteomes. http://www.channel-proteomes.com/projects/cav2env/proteins/P62989. Retrieved 2011-10-12. 
  13. ^ Ron Milo. "How big is the “average” protein?". http://www.weizmann.ac.il/plants/Milo/images/proteinSize110623Clean.pdf. Retrieved 2011-10-13. 
  14. ^ Van Beekvelt MC, Colier WN, Wevers RA, Van Engelen BG (Feb 2001). "Performance of near-infrared spectroscopy in measuring local O2 consumption and blood flow in skeletal muscle". J Appl Physiol 90 (2): 511–519. ISSN 8750-7587. PMID 11160049. http://jap.physiology.org/cgi/pmidlookup?view=long&pmid=11160049. 
  15. ^ From attograms to Daltons: Cornell NEMS device detects the mass of a single DNA molecule [1]. Retrieved 2010-10-14
  16. ^ a b "Eukaryotic Ribosome". ETH Zurich. http://www.mol.biol.ethz.ch/groups/ban_group/Ribosome. Retrieved 2011-10-09. 
  17. ^ Bockstahler, L.; Kaesberg, P. (1962). "The Molecular Weight and Other Biophysical Properties of Bromegrass Mosaic Virus". Biophysical Journal 2 (1): 1–9. doi:10.1016/S0006-3495(62)86836-2. PMC 1366384. PMID 19431313. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1366384.  edit
  18. ^ "Atomic mass of synaptic vesicle - Rat Rattus". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?s=n&id=102736. Retrieved 2011-10-09. 
  19. ^ "Molecular weight - Tobacco mosaic virus (TMV) - BNID 105958". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?s=y&id=105958&lnsh=1. Retrieved 2011-10-09. 
  20. ^ Rout, M. P.; Blobel, G. (1993). "Isolation of the yeast nuclear pore complex". The Journal of Cell Biology 123 (4): 771–783. doi:10.1083/jcb.123.4.771. PMC 2200146. PMID 8227139. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2200146.  edit
  21. ^ Liu, H.; Jin, L.; Koh, S. B. S.; Atanasov, I.; Schein, S.; Wu, L.; Zhou, Z. H. (2010). "Atomic Structure of Human Adenovirus by Cryo-EM Reveals Interactions Among Protein Networks". Science 329 (5995): 1038–1043. doi:10.1126/science.1187433. PMID 20798312. http://virology.cornell.edu/Liu.pdf.  edit
  22. ^ "Virus diameter of HIV-1 - HIV". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?&id=101667&ver=10. Retrieved 2011-11-01. 
  23. ^ Calculated : volume = 4/3 * pi * (126e-9 m / 2)^3 = 1.05e-21 m^3. Assume density = 1 g/cm^3 => mass = 1.05e-21 m^3 * 1e3 kg/m^3 = 1.05e-18 kg
  24. ^ Frederick R. Blattner, Guy Plunkett III, et al. (1997). "The Complete Genome Sequence of Escherichia coli K-12". Science 277 (5331): 1453–1462. doi:10.1126/science.277.5331.1453. PMID 9278503. http://www.sciencemag.org/cgi/content/abstract/277/5331/1453. 
  25. ^ "Mass of virion - Virus Vaccinia". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?&id=106860&ver=2. Retrieved 2011-11-01. 
  26. ^ "Conversion from J to kg". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Convert?exp=0&num=1&From=j&To=kg&Action=Convert+value+and+show+factor. Retrieved 2011-08-23. 
  27. ^ "Prochlorococcus marinus MIT 9313 - Home". Joint Genome Institute. http://genome.jgi-psf.org/prom9/prom9.home.html. Retrieved 2011-11-01. 
  28. ^ "Size (diameter) of most abundant cyanobacteri - Prochlorococcus - BNID 101520". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?&id=101520&ver=6. Retrieved 2011-11-01. 
  29. ^ a b c Mass calculated from volume assuming density of 1 g/mL
  30. ^ "E. coli Statistics". The CyberCell Database. http://www.ccdb.ualberta.ca/CCDB/cgi-bin/STAT_NEW.cgi. Retrieved 2011-09-11. 
  31. ^ "What is the total mass of DNA in the average 65kg human body?". Quora. http://www.quora.com/What-is-the-total-mass-of-DNA-in-the-average-65kg-human-body. Retrieved 2011-08-23. 
  32. ^ "Surface area and volume of spermatozoa - Human Homo sapiens". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?&id=106852&ver=1. Retrieved 2011-11-01. 
  33. ^ Ron Milo. "How big is a yeast cell and what is it’s mass". http://www.weizmann.ac.il/plants/Milo/images/YeastSize-Feb2010.pdf. Retrieved 2011-10-09. 
  34. ^ ""Rule of thumb" for cell mass". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?s=y&id=101795&hlid=64639. Retrieved 2011-10-09. 
  35. ^ "Cell dry weight - Green algae Dunaliella salina". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?s=n&id=106042. Retrieved 2011-10-14. 
  36. ^ "Measured HeLa cell mass". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?s=n&id=103721. Retrieved 2011-10-09. 
  37. ^ "Estimated HeLa cell mass". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?s=n&id=103720. Retrieved 2011-10-09. 
  38. ^ "Volume of human oocyte - Human Homo sapiens". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?&id=101664&ver=7. Retrieved 2011-11-01. 
  39. ^ "Dietary Supplement Fact Sheet: Vitamin B12". Office of Dietary Supplements. http://ods.od.nih.gov/factsheets/VitaminB12. Retrieved 2011-10-02. 
  40. ^ "Dietary Supplement Fact Sheet: Vitamin D". Office of Dietary Supplements. http://ods.od.nih.gov/factsheets/vitamind. Retrieved 2011-10-02. 
  41. ^ "CODATA Value: Planck mass". The NIST Reference on Constants, Units, and Uncertainty. NIST. http://physics.nist.gov/cgi-bin/cuu/Value?plkm. Retrieved 2011-09-30. 
  42. ^ "Weigh An Eyelash". National Semiconductor. http://www.national.com/en/videos/MiligramScale.html. Retrieved 2011-10-02. 
  43. ^ "Dietary Supplement Fact Sheet: Iodine". Office of Dietary Supplements. http://ods.od.nih.gov/factsheets/Iodine-QuickFacts. Retrieved 2011-10-02. 
  44. ^ "Mean dry mass (male) - Fruit fly". BioNumbers. http://bionumbers.hms.harvard.edu/bionumber.aspx?id=102570. Retrieved 2011-10-14. 
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  46. ^ "Frequently Asked Questions". American Mosquito Control Association. http://www.mosquito.org/index.php?option=com_content&view=article&id=45&Itemid=122#weigh. Retrieved 2011-08-23. 
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