--------------------------------- Scales of Measurement Version 1.7 --------------------------------- This is a copy of the scales of measurement list that I have been making. Thanks to the many people who gave me suggestions about earlier versions. I would be grateful for factual and grammar corrections. I would also like to know if people have specific objects that they think should be included in these scales. I am interested in objects which do the following things: A. Illustrate a physical principle (for example, the Compton length as a basic quantum "fuzziness" length) B. Are particularly fantastic (for example, the LIGO project wants to look for length fluctuations smaller than a nuclear diameter) C. Fill in holes in my order-of-magnitude scale D. Are especially interesting for some other reason I would be grateful for suggestions as to how to better word specific entries so as to make them maximally illuminating in the available space. Please send any comments/suggestions/corrections to me via email. An XMOSAIC page has been created for my timelines and scales of measurement list. The URL is the following: http://xalph.ast.cam.ac.uk/niel/scales.html If you are not able to obtain one of my lists via XMOSAIC or usenet, please send me an email request and I will email you the list you want. Please specify desired format (ASCII or TEX). Thank you, Niel Brandt niel@ast.cam.ac.uk This document is copyright Niel Brandt 1994. You are allowed to copy, distribute, and edit this document at will without any obligation as long as you do not remove the above header. Reproduction and distribution for personal profit is not permitted. --------------------------------------------------------------------- SCALES OF MEASUREMENT VERSION 1.7 William Nielsen Brandt --- niel@ast.cam.ac.uk 3 x 10^{-6} arcseconds Angular size of a 10^8 solar mass Schwarzschild black hole in M31 0.0002 arcseconds Typical VLBA resolution at 43 GHz 0.0005 arcseconds Person on the Moon 0.001 arcseconds Typical VLBI resolution 0.0015 arcseconds Hipparcos satellite astrometric positional accuracy 0.04 arcseconds Hubble Space Telescope FOC optical angular resolution 0.1 arcseconds VLA largest configuration resolution at 23 GHz 0.1 arcseconds Hubble Space Telescope WFC optical angular resolution 0.15 arcseconds 1 meter optical reflector yellow light diffraction limit 0.5 arcseconds WHT MARTINI guide star system resolution 0.6 arcseconds Rough optical telescope atmospheric seeing limit 0.8 arcseconds Angular diameter of Europa 1 arcseconds AXAF X-ray satellite angular resolution goal 1.32 arcseconds Yearly proper motion of Sirius 1.75 arcseconds Gravitational deflection of a light ray which grazes the Sun 2.9 arcseconds Angular diameter of a M31 sized galaxy at z=0.5 in optical light 5 arcseconds ROSAT X-ray satellite HRI angular resolution 8 arcseconds Angular separation of the gravitationally lensed quasar 0957+561 25 arcseconds ROSAT X-ray satellite PSPC angular resolution 36 arcseconds Angular diameter of Jupiter 120 arcseconds Human eye resolution 120 arcseconds Typical optical telescope field of view 150 arcseconds Rough Crab Nebula radius 210 arcseconds Rough Cir X-1 radio nebula radius 400 arcseconds Cluster imprint on the cosmic microwave background radiation 480 arcseconds OVRO 5.5 meter 32 GHz telescope resolution 700 arcseconds Jodrell bank 250 foot 1420.4 MHz telescope resolution 1200 arcseconds ROSAT X-ray satellite HRI field of view radius 1500 arcseconds ASCA X-ray satellite GIS field of view radius 1865 arcseconds Angular diameter of the Moon at its mean distance 1800 arcseconds 100 Mpc structure imprint on the cosmic microwave background radiation 1922 arcseconds Angular diameter of the Sun at its mean distance 3100 arcseconds Maximum angular scale of causal connection on the cosmic microwave background radiation 3600 arcseconds ROSAT X-ray satellite PSPC field of view radius 7500 arcseconds Angular diameter of W50 10800 arcseconds Angular diameter of the LMC 14400 arcseconds Angular diameter of M31 in optical light 19800 arcseconds Palomar Optical Sky Survey plate field of view 25200 arcseconds COBE DMR resolution limit 5 x 10^{-44} seconds Planck-Wheeler time 4 x 10^{-24} seconds Typical lifetime of strong interaction resonance 8 x 10^{-21} seconds Electron light crossing time 1 x 10^{-13} seconds Typical period of vibration of an atom in a solid 1 x 10^{-13} seconds Typical X-ray line electric dipole radiative transition time 1.6 x 10^{-9} seconds Typical hydrogen 2p ---> 1s radiative transition time (electric dipole one photon process) 8 x 10^{-4} seconds Mass shedding minimum spin period for a neutron star 1.6 x 10^{-3} seconds Spin period of PSR 1957+20 0.12 seconds Typical hydrogen 2s ---> 1s radiative transition time (strictly forbidden two photon process) 10 seconds Median duration of a classical gamma-ray burst 2 000 seconds Sun dynamic time scale 8.6 x 10^{4} seconds Earth rotation time 3.2 x 10^{7} seconds Earth orbit time around the Sun 1.6 x 10^{9} seconds Typical time between Milky Way supernovae 1.9 x 10^{11} seconds Carbon-14 half-life 3 x 10^{12} seconds Rough lifetime of a supernova remnant 1.5 x 10^{13} seconds Typical HMXB evolution time 3 x 10^{13} seconds Rough time for evolution of a biological species 1.6 x 10^{14} seconds Main sequence lifetime for a 30 solar mass star 3 x 10^{14} seconds Hydrogen 21 cm spin flip time 3 x 10^{14} seconds Rough Lyapunov time of the solar system 6.3 x 10^{14} seconds Sun thermal time scale 1.3 x 10^{15} seconds E-folding time for a black hole accreting at the Eddington rate with an efficiency of 0.1 1.9 x 10^{15} seconds Main sequence lifetime for a 5 solar mass star 2 x 10^{15} seconds Timescale for Los Angeles to pass San Francisco via continental drift 2.4 x 10^{15} seconds Typical LMXB evolution time 7.3 x 10^{15} seconds Orbit time for sun around galaxy center 1.1 x 10^{16} seconds PSR 1913+16 orbital gravitational radiation coalescence timescale 2 x 10^{16} seconds Rough supernova biological extinction time 6 x 10^{16} seconds Minimum age of PSR J0437-4715 6 x 10^{16} seconds Time for galaxy to cross a cluster 1.1 x 10^{17} seconds Primeval slime to man time 1.5 x 10^{17} seconds Age of Earth and Sun 1.5 x 10^{17} seconds Uranium-238 half-life 2.7 x 10^{17} seconds Look back time to z=1 3 x 10^{17} seconds Main sequence lifetime for a 1 solar mass star 3.3 x 10^{17} seconds Look back time to z=2 3.3 x 10^{17} seconds Sun nuclear time scale 3.7 x 10^{17} seconds Look back time to z=4 3.8 x 10^{17} seconds Rough age of the Milky Way 3.8 x 10^{17} seconds Look back time to the z=4.897 quasar PC 1247+3406 4 x 10^{17} seconds Rough age of 47 Tucanae (an old globular cluster) 4.1 x 10^{17} seconds Age of the universe 2.5 x 10^{18} seconds Globular cluster evaporation time 3 x 10^{25} seconds Galaxy dynamical relaxation timescale 3 x 10^{27} seconds Earth/Sun orbital gravitational radiation coalescence timescale 1 x 10^{39} seconds Lower limit on the proton lifetime 4.7 x 10^{73} seconds 1 solar mass black hole Hawking evaporation time 1.6 x 10^{-35} meters Planck-Wheeler length 2 x 10^{-35} meters Rough postulated superstring size 1 x 10^{-24} meters Effective 1 MeV neutrino radius 1.6 x 10^{-22} meters Radius of a 10 solar mass star squeezed down to the Planck-Wheeler density 1.5 x 10^{-18} meters Classical proton radius 1.6 x 10^{-17} meters W +/- Compton wavelength = rough weak force length 4 x 10^{-17} meters LIGO 4 km gravity-wave detector needed sensitivity 1.3 x 10^{-15} meters Proton Compton wavelength = rough proton fuzziness length 1.44 x 10^{-15} meters Rough nuclear radius 2.8 x 10^{-15} meters Classical electron radius 8.8 x 10^{-15} meters Pi-meson Compton wavelength = attractive strong force length 1.2 x 10^{-12} meters 1 MeV gamma-ray wavelength 2.4 x 10^{-12} meters Electron Compton wavelength = rough electron fuzziness length 5.3 x 10^{-11} meters Bohr radius 2.6 x 10^{-10} meters Copper atom spacing in solid copper 3.5 x 10^{-10} meters H2O molecular diameter 4 x 10^{-10} meters ROSAT X-ray satellite mirror rms surface error 1.2 x 10^{-9} meters 1 keV X-ray wavelength 3 x 10^{-9} meters Typical mean nucleon spacing during primordial nucleosynthesis 3.4 x 10^{-9} meters DNA double helix turn length 6 x 10^{-8} meters Typical rms surface error of a Keck telescope mirror 7.0 x 10^{-8} meters Molecular mean free path in the atmosphere 1 x 10^{-7} meters Typical size of a virus 3 x 10^{-7} meters Interstellar dust grain size 5 x 10^{-7} meters Optical photon wavelength 4 x 10^{-6} meters Typical size of a cell 2 x 10^{-4} meters Small dust particle size 0.03 meters Lunar laser ranging accuracy (Science 265, 482) 0.068 meters Unraveled human DNA strand length 1.8 meters Man 30 meters Blue Whale 3700 meters Mean ocean depth 4000 meters Error in our knowledge of the distance to Jupiter 5500 meters Rough radius of Halley's comet 8847 meters Height of Mount Everest 10000 meters Neutron star radius 10000 meters Typical asteroid radius 10000 meters Typical comet radius 11032 meters Depth of the Mariana Trench 12000 meters Height of troposphere 12000 meters Typical airliner cruising altitute 30000 meters Typical thickness of the Earth's crust 5.5 x 10^{5} meters Height of the ASCA X-ray satellite orbit 9 x 10^{5} meters Height of the COBE satellite orbit 3.2 x 10^{6} meters Length of the Great Wall of China 6.3 x 10^{6} meters Radius of the Earth 4.2 x 10^{7} meters Geostationary satellite orbit height 7.1 x 10^{7} meters Radius of Jupiter 9 x 10^{7} meters Distance to the Earth's solar wind bow shock 3.8 x 10^{8} meters Distance to the Moon 7.0 x 10^{8} meters Radius of the Sun 1 x 10^{9} meters Typical X-ray binary accretion disk circularization radius 1.7 x 10^{9} meters 5 solar mass star main sequence radius 7 x 10^{9} meters Typical standoff radius of Jupiter's solar wind bow shock 1.47 x 10^{11} meters Event horizon radius for a 10^8 solar mass maximally rotating Kerr black hole 1.50 x 10^{11} meters Earth/Sun mean distance 1.5 x 10^{11} meters Radius of the red giant Mira at minimum light 3 x 10^{11} meters Radius of the red giant Mira at maximum light 5 x 10^{11} meters Radius of the 20 solar mass red supergiant Betelgeuse at maximum light 5.91 x 10^{12} meters Pluto/Sun mean distance 1.5 x 10^{13} meters Expected distance to the solar wind termination shock 2 x 10^{14} meters Rough stellar separation in the central parsec of the Milky Way 4 x 10^{14} meters Rough stellar separation in a globular cluster 2 x 10^{15} meters Rough Oort Cloud/Sun distance 3 x 10^{15} meters Seyfert galaxy characteristic broad line region radius 9.46 x 10^{15} meters 1 light-year 3.08 x 10^{16} meters 1 parsec 4 x 10^{16} meters Nearest nonsolar star to Earth 4.5 x 10^{16} meters Rough Crab Nebula radius 3 x 10^{17} meters Rough Cir X-1 radio nebula radius 3 x 10^{17} meters Rough supernova biological extinction distance 5 x 10^{17} meters Typical interstellar medium cloud size 1.4 x 10^{18} meters Hyades open cluster distance 1.5 x 10^{18} meters Trigonometric parallax distance determination limit 1.5 x 10^{18} meters Typical globular cluster radius 2 x 10^{18} meters Rough radius of the local interstellar hot gas bubble 5 x 10^{18} meters Seyfert galaxy characteristic narrow line region radius 5 x 10^{18} meters Diameter of W50 5.2 x 10^{18} meters Distance to the 20 solar mass red supergiant Betelgeuse (will go supernova within 10000 years) 6 x 10^{19} meters Typical dwarf galaxy radius 6.6 x 10^{19} meters Distance to the Crab Nebula 1.2 x 10^{20} meters Milky Way characteristic thickness 2 x 10^{20} meters Estimated distance to Cir X-1 2.4 x 10^{20} meters Distance from Sun to galactic center 3.9 x 10^{20} meters Milky Way disk radius 1.5 x 10^{21} meters Distance to the LMC 2 x 10^{21} meters Rough Milky Way dark matter halo radius 1 x 10^{22} meters Typical active galaxy jet length 1 x 10^{22} meters Length of the ``superantennae'' of IRAS 19254-7245 1.9 x 10^{22} meters Distance to M31 3 x 10^{22} meters Radius of the core of the Virgo cluster of galaxies 4 x 10^{22} meters Rough Local Group radius 9.2 x 10^{22} meters Cepheid variable distance determination limit (via ground observations) 1.2 x 10^{23} meters Distance to the Circinus galaxy 5 x 10^{23} meters Rough boundary between the nonlinear and linear gravitational collapse regimes 7 x 10^{23} meters Distance to NGC 1068 7 x 10^{23} meters Distance to the center of the Virgo cluster of galaxies 2.3 x 10^{24} meters Shapley supercluster radius 3 x 10^{24} meters Typical length scale probed by the Harvard/Smithsonian CfA redshift survey 4.1 x 10^{24} meters Luminosity distance to the z=0.022 Coma cluster of galaxies 1.5 x 10^{25} meters Typical length scale probed by the Lick survey 3.0 x 10^{25} meters Luminosity distance to the z=0.158 quasar 3C273 3 x 10^{25} meters Typical length scale probed by the 4C radio galaxy survey 3 x 10^{25} meters Schwarzschild radius of a singularity with the mass of a critical density universe 5.5 x 10^{26} meters Luminosity distance to the z=2.286 ultraluminous IRAS galaxy IRAS F10214+4724 1.3 x 10^{27} meters Luminosity distance to the z=4.897 quasar PC 1247+3406 1 x 10^{-9} m s^{-1} Sea floor spreading rate 1.6 x 10^{-9} m s^{-1} Average slip rate of the San Andreas fault 1 x 10^{-8} m s^{-1} Typical rainfall rate in a semi-arid climate 2 x 10^{-8} m s^{-1} Grass growth rate 3 x 10^{-6} m s^{-1} Typical glacial advance rate 1 x 10^{-3} m s^{-1} Equivalent radial velocity resolution of pulsar pulse arrival time analysis 1.3 m s^{-1} Human walking speed 10 m s^{-1} Speed of the motion induced on the Sun by Jupiter 10 m s^{-1} Radial velocity resolution of high precision Doppler spectroscopy 25 m s^{-1} Car speed 100 m s^{-1} Typical speed of an electric pulse in the nervous system 330 m s^{-1} Sound speed in air 480 m s^{-1} Earth's atmosphere molecular rms velocity 600 m s^{-1} Fighter jet speed 2380 m s^{-1} Escape velocity from Moon's surface 10000 m s^{-1} Typical longitudinal seismic wave velocity in the Earth's mantle 11000 m s^{-1} Escape velocity from the Earth's surface 20000 m s^{-1} Globular cluster stellar velocity dispersion 29000 m s^{-1} Earth's motion around the Sun 40000 m s^{-1} Globular cluster stellar escape velocity 1 x 10^{5} m s^{-1} Typical Galactic pulsar vertical velocity component 1 x 10^{5} m s^{-1} Average speed of the initial stroke of a lightning flash 2.2 x 10^{5} m s^{-1} Rotational velocity of the Sun around the Milky Way's center 3 x 10^{5} m s^{-1} Orbital speed of PSR 1913+16 3 x 10^{5} m s^{-1} Rough velocity of Geminga's proper motion 3.1 x 10^{5} m s^{-1} Escape velocity from the Milky Way for objects in the solar neighborhood 3.65 x 10^{5} m s^{-1} Motion of the solar system barycenter relative to the cosmic microwave background 4.1 x 10^{5} m s^{-1} Orbital speed of Cen X-3 6.2 x 10^{5} m s^{-1} Escape velocity from the Sun's surface 6.22 x 10^{5} m s^{-1} Motion of the Local Group relative to the cosmic microwave background 8 x 10^{5} m s^{-1} Typical galaxy cluster galaxy velocity dispersion 2 x 10^{6} m s^{-1} Speed of n=1 hydrogen electron 5 x 10^{6} m s^{-1} Young (months old) supernova ejecta 1.2 x 10^{7} m s^{-1} Velocity of the wind streaming out from H1413+117 ``Cloverleaf'' (Nature 371, 559) 7.8 x 10^{7} m s^{-1} SS433 jet speed 1.4 x 10^{8} m s^{-1} Keplerian orbital velocity at the surface of a neutron star 2 x 10^{8} m s^{-1} Escape velocity from neutron star surface 2.998 x 10^{8} m s^{-1} Light in a vacuum 4.2 x 10^{-36} kilograms Mass equivalent of a green light photon 1.4 x 10^{-35} kilograms Electron antineutrino upper mass limit 4.4 x 10^{-31} kilograms Muon neutrino upper mass limit 9.11 x 10^{-31} kilograms Electron mass 6.2 x 10^{-29} kilograms Tauon neutrino upper mass limit 1.67 x 10^{-27} kilograms Proton mass 9 x 10^{-27} kilograms Bottom quark mass 4.8 x 10^{-26} kilograms Mean mass of atmosphere molecule 1.4 x 10^{-25} kilograms W +/- mass (82 GeV) 1.6 x 10^{-25} kilograms Z^0 mass (93 GeV) 2 x 10^{-25} kilograms Favored Higgs boson mass 3 x 10^{-25} kilograms Most probable top quark mass 4 x 10^{-25} kilograms DNA nucleotide 1 x 10^{-22} kilograms Typical protein molecule mass 5 x 10^{-21} kilograms E. Coli ribosome 1 x 10^{-16} kilograms Interstellar dust grain mass 8 x 10^{-15} kilograms Rough mass of a human DNA molecule 7 x 10^{-13} kilograms Typical mass of a cell 2.2 x 10^{-8} kilograms Planck-Wheeler mass 1 x 10^{-5} kilograms Typical mosquito mass 0.02 kilograms Typical goldfish mass 70 kilograms Typical human mass 70 kilograms Lower limit to the allowed mass for a Sumo wrestler 100 kilograms Meteorite mass before entry into Earth's atmosphere 420 kilograms ASCA X-ray satellite mass 900 kilograms Compton Gamma-Ray Observatory satellite mass 1000 kilograms Car 2200 kilograms ISO infrared satellite mass at launch 10000 kilograms Tyrannosaurus Rex 5 x 10^{11} kilograms Initial mass of a primordial black hole with evaporation time equal to the universe's age 1 x 10^{13} kilograms Typical comet mass 3 x 10^{14} kilograms Typical mountain mass 1.1 x 10^{16} kilograms Superterranean biomass of Earth (ocean organisms are included) 5.3 x 10^{18} kilograms Total mass of Earth's atmosphere 3 x 10^{19} kilograms Typical asteroid mass 1.4 x 10^{21} kilograms Total mass of Earth's oceans 4.8 x 10^{22} kilograms Mass of Europa 7.3 x 10^{22} kilograms Mass of the Moon 2 x 10^{24} kilograms Rough Oort cloud mass 5.98 x 10^{24} kilograms Mass of the Earth 1.9 x 10^{27} kilograms Mass of Jupiter 1.6 x 10^{29} kilograms Minimum mass to fusion burn hydrogen 4 x 10^{29} kilograms Rough mass of MACHO and EROS microlensing objects 1.99 x 10^{30} kilograms Mass of the Sun 2.8 x 10^{30} kilograms Chandrasekhar mass (maximum mass for a white dwarf) 6.0 x 10^{30} kilograms Oppenheimer-Volkoff mass (maximum mass for a neutron star) 1.2 x 10^{31} kilograms Minimum mass of the unseen object in GS2023+338/V404 Cygni 4 x 10^{31} kilograms Rough stellar mass above which the evolutionary endpoint is a black hole 1.0 x 10^{32} kilograms Mass of the most massive member of Plaskett's star 1.2 x 10^{32} kilograms Rough mass at which a star becomes unstable to pulsations 2 x 10^{33} kilograms Typical interstellar cloud mass 1 x 10^{36} kilograms Typical mass of a globular cluster 6 x 10^{36} kilograms Best guess for the mass of a possible Milky Way central black hole 1 x 10^{37} kilograms Rough baryonic Jeans mass immediately after decoupling 4 x 10^{39} kilograms Rough mass of the SMC 2 x 10^{40} kilograms Rough mass of the LMC 7 x 10^{41} kilograms Rough mass of the Milky Way (visible and dark matter) 1.3 x 10^{44} kilograms Rough mass of the stars in the Coma galaxy cluster 6.4 x 10^{44} kilograms Rough mass of the X-ray gas in the Coma galaxy cluster 2.7 x 10^{45} kilograms Rough virial mass of the Coma galaxy cluster 6 x 10^{45} kilograms Rough virial mass of the Abell 2163 galaxy cluster 2 x 10^{48} kilograms Rough baryonic Jeans mass immediately before decoupling 1.4 x 10^{49} kilograms Rough total mass in spiral galaxies 2 x 10^{49} kilograms Rough total (baryonic and nonbaryonic) mass in galaxy clusters 3 x 10^{49} kilograms Rough total mass in elliptical and spheroidal galaxies 8 x 10^{49} kilograms Rough total mass of visible matter in the universe 1 x 10^{51} kilograms Rough total baryon mass predicted by primordial nucleosynthesis 2 x 10^{52} kilograms Rough total mass of a critical density universe 2 x 10^{-38} kg m^{-3} Effective density of the 100-300 MHz radio background 1 x 10^{-35} kg m^{-3} Effective density of the 1--10 MeV gamma-ray background 8 x 10^{-35} kg m^{-3} Effective density of the 2--100 keV X-ray background 1.1 x 10^{-33} kg m^{-3} Upper limit to the effective density of the gravitational wave background 1 x 10^{-32} kg m^{-3} Effective density of the starlight released in a Hubble time 4.6 x 10^{-31} kg m^{-3} Effective density of the cosmic microwave background radiation 2 x 10^{-29} kg m^{-3} Smoothed density of visible galactic material throughout universe 2 x 10^{-28} kg m^{-3} Smoothed baryon density predicted by primordial nucleosynthesis 4.7 x 10^{-27} kg m^{-3} Critical density of the universe 2 x 10^{-24} kg m^{-3} Typical gas in a cluster of galaxies 3 x 10^{-21} kg m^{-3} Typical gas in the interstellar medium of the Milky Way 7 x 10^{-21} kg m^{-3} Dynamically inferred Milky Way disk density 5 x 10^{-20} kg m^{-3} Typical density of the gas in the central kiloparsec of an interacting or starburst galaxy 1 x 10^{-9} kg m^{-3} Best room temperature vacuum achieved on Earth 1.7 x 10^{-4} kg m^{-3} Mean density of Antares (19 solar masses) 1.3 kg m^{-3} Density of air 700 kg m^{-3} Mean density of Saturn 1000 kg m^{-3} Density of water 1300 kg m^{-3} Mean density of Jupiter 1400 kg m^{-3} Mean density of the Sun 3300 kg m^{-3} Mean density of the Moon 5500 kg m^{-3} Mean density of the Earth 7860 kg m^{-3} Density of iron 19300 kg m^{-3} Density of gold 5 x 10^{7} kg m^{-3} Typical white dwarf mean density 3 x 10^{10} kg m^{-3} Typical white dwarf central density 1.1 x 10^{12} kg m^{-3} Inverse beta decay threshold 4.3 x 10^{14} kg m^{-3} Neutron drip density 6 x 10^{17} kg m^{-3} Nuclear density 1 x 10^{18} kg m^{-3} Typical neutron star central density 5 x 10^{96} kg m^{-3} Planck-Wheeler density, at which quantum gravitational effects become important 6 x 10^{-25} joules Lamb-Retherford shift 9.5 x 10^{-25} joules 21.049 cm photon---hyperfine shift 4 x 10^{-22} joules Molecular rotation transition 4 x 10^{-21} joules kT_room = translational kinetic energy of atmosphere gas molecule 7 x 10^{-21} joules Donor level/conduction band gap in a doped semiconductor 3 x 10^{-20} joules Molecular vibration transition 1.6 x 10^{-19} joules Valence band/conduction band gap in a semiconductor 2.2 x 10^{-19} joules Bond energy of an organic substance with half-life 30000 years 3.8 x 10^{-19} joules Green light photon 9 x 10^{-19} joules Valence band/conduction band gap in an insulator 1.1 x 10^{-18} joules Fermi energy in copper = depth of Fermi sea 1.1 x 10^{-18} joules Positronium ionization energy 2.2 x 10^{-18} joules Hydrogen n=1 binding energy 1.6 x 10^{-16} joules 1 keV X-ray 1.5 x 10^{-15} joules Hydrogenic iron n=1 binding energy 8.18 x 10^{-14} joules Electron rest mass 1.6 x 10^{-13} joules 1 MeV gamma-ray 1.6 x 10^{-13} (Z_1 x Z_2) joules Coulomb barrier height 1.3 x 10^{-12} joules Nucleon binding energy 4.3 x 10^{-12} joules Energy from 4 x ^1 H ---> ^4 He 1.50 x 10^{-10} joules Proton rest mass 1.6 x 10^{-7} joules Particle kinetic energy in a 1 TeV accelerator 10 joules Well hit tennis ball 51 joules Fly's Eye most energetic cosmic ray event 2 x 10^{5} joules Energy from a light bulb burning for 1 hour 4.2 x 10^{9} joules Explosion energy of 1 ton of TNT 2 x 10^{10} joules Rough energy of a lightning flash 2 x 10^{11} joules Rough human total energy output in a lifetime 1.5 x 10^{14} joules Typical atomic bomb explosion energy 6 x 10^{16} joules Tunguska 50 m diameter meteorite impact energy 1 x 10^{17} joules Powerful H-bomb explosion energy 3 x 10^{17} joules Elastic wave energy release from a large (M=8.5) earthquake 5 x 10^{17} joules Explosion energy of Krakatoa 3 x 10^{18} joules Superman flying at 70 per cent of light speed 9 x 10^{18} joules USA electricity usage in 1986 5 x 10^{19} joules Rough explosion energy of the Lake Toba eruption in Sumatra 4 x 10^{23} joules K-T 10 km diameter meteorite impact energy 2.5 x 10^{22} joules Energy from the comet Shoemaker-Levy 9 fragment G impact on Jupiter 1 x 10^{24} joules Power released by an evaporating black hole during the last second of its life 2.1 x 10^{29} joules The Earth's rotational energy 3 x 10^{31} joules The Earth's total heat content 7 x 10^{34} joules Total rotational energy of the planets 2.5 x 10^{35} joules Rotational energy of the Sun 3 x 10^{36} joules Gravitational internal binding energy of Jupiter 6 x 10^{37} joules Nova Persei outburst 3 x 10^{41} joules A 450 km s^{-1} neutron star kick 3 x 10^{43} joules Energy needed to make the local superbubble 1.3 x 10^{44} joules Total radiant energy from the Sun 3 x 10^{44} joules Energy in photons from a type II supernova explosion 3 x 10^{46} joules Energy in neutrinos from a type II supernova explosion 2 x 10^{53} joules Typical gravitational binding energy of a galaxy 2 x 10^{54} joules Typical magnetic and kinetic energy in a large radio lobe (Shu 311) 5.2 x 10^{54} joules Rotational energy of a 10^8 solar mass maximal Kerr black hole 5 x 10^{57} joules Typical gravitational binding energy of a cluster of galaxies 2 x 10^{7} joules kg^{-1} Efficiency of the metabolism of food 1.3 x 10^{13} joules kg^{-1} Efficiency of dropping matter onto a white dwarf 6.3 x 10^{14} joules kg^{-1} Efficiency of fusion burning hydrogen 5.1 x 10^{15} joules kg^{-1} Slowly spiraling accretion onto a Schwarzschild black hole 7.5 x 10^{15} joules kg^{-1} Shakura-Sunyaev efficiency for accretion onto a Newtonian ``black hole'' 8 x 10^{15} joules kg^{-1} Efficiency of dropping matter onto a neutron star 2.6 x 10^{16} joules kg^{-1} Slowly spiraling prograde accretion onto a realistically maximally rotating Kerr black hole 3.8 x 10^{16} joules kg^{-1} Slowly spiraling prograde accretion onto a theoretically maximally rotating Kerr black hole 8.99 x 10^{16} joules kg^{-1} Efficiency of matter-antimatter annihilation 4 x 10^{-6} watts Average energy output from 1 kilogram of the Milky Way 1 x 10^{-3} watts Optical disc player laser 6 watts Amateur short wave radio transmitter 60 watts Light bulb 100 watts Gravitational wave power from the Earth-Sun system 150 watts Human being under normal conditions 750 watts Maximum long duration horse output 1500 watts Typical fireplace fire 20000 watts Car 1 x 10^{5} watts Running Tyrannosaurus Rex 3 x 10^{8} watts Nuclear power reactor 3 x 10^{8} watts Moderate thunderstorm electrical power generation rate 1.3 x 10^{9} watts Hoover dam 3 x 10^{11} watts USA average electricity usage rate in 1986 1 x 10^{13} watts Solar radio luminosity 8 x 10^{13} watts Powerful nanosecond pulse laser 1.7 x 10^{17} watts Insolation of Earth 1 x 10^{23} watts Typical white dwarf luminosity 8 x 10^{24} watts Gravitational wave radiation from PSR 1913+16 3.9 x 10^{26} watts Solar luminosity 5 x 10^{26} watts The 2--10 keV flux of the cataclysmic variable FO Aquarii 1 x 10^{28} watts Typical X-ray luminosity of an X-ray pulsar 1 x 10^{28} watts X-ray luminosity associated with Sgr A* 3.5 x 10^{28} watts Rotational energy loss rate from the Geminga pulsar 2.4 x 10^{29} watts 5 solar mass star on main sequence 4 x 10^{30} watts Cygnus X-1 X-ray luminosity 5.5 x 10^{30} watts Luminosity of the 20 solar mass red supergiant Betelgeuse at maximum light 1 x 10^{31} watts Crab Nebula energy output 2 x 10^{31} watts Eddington limit for a 1.4 solar mass neutron star 3 x 10^{31} watts Typical luminosity of Cir X-1 in zero phase 1 x 10^{33} watts Rough luminosity of Eta Carinae in April 1843 5 x 10^{35} watts Type II supernova peak photon luminosity 3 x 10^{36} watts Milky Way 1.5 x 10^{38} watts Coma cluster X-ray gas luminosity 1 x 10^{39} watts 10^8 solar mass black hole accreting at 1/10 of the Eddington limit 1 x 10^{39} watts Typical quasar luminosity 1 x 10^{40} watts Rough luminosity of the quasar 3C273 2 x 10^{41} watts Rough luminosity of the z=2.286 ultraluminous IRAS galaxy IRAS F10214+4724 1 x 10^{42} watts Rough luminosity of a cosmological gamma-ray burst 7 x 10^{-7} kelvins Laser cooling of cesium atoms 1.3 x 10^{-5} kelvins Cosmic microwave background quadrupole anisotropy 5 x 10^{-4} kelvins Typical Sunyaev-Zel'dovich cosmic microwave background decrement 3.3 x 10^{-3} kelvins Cosmic microwave background dipole anisotropy 0.01 kelvins Typical limit of liquid helium dilution cooling 0.3 kelvins Typical limit of liquid helium evaporation cooling 2.17 kelvins Liquid ^4 He superfluid transition temperature 2.726 kelvins Cosmic microwave background temperature today 3.20 kelvins Liquid ^3 He boiling point 4 kelvins Typical limit of Joule-Thomson effect cooling 4.18 kelvins Liquid ^4 He boiling point 6 kelvins Typical noise temperature of a HEMT receiver at 30 GHz 12 kelvins Lanthanum (under pressure) superconductivity critical temperature (highest for a pure element) 20 kelvins Liquid H_2 boiling temperature 77 kelvins Liquid N_2 boiling temperature 133 kelvins Mercury-barium-calcium-copper oxide compound superconductivity critical temperature 273 kelvins Water freezing temperature 311 kelvins Human surface temperature 373 kelvins Water boiling temperature 388 kelvins Brimstone melting temperature---upper limit to the temperature of Hell 506 kelvins Paper burning temperature 740 kelvins Typical surface temperature of Venus 1811 kelvins Melting temperature of iron 3000 kelvins Cosmic microwave background temperature at decoupling 5770 kelvins Solar effective temperature 5 x 10^{5} kelvins Surface temperature of the Geminga pulsar 3 x 10^{6} kelvins Polar cap temperature of the Geminga pulsar 3 x 10^{6} kelvins Typical fusion experiment 1.4 x 10^{7} kelvins Center of the Sun 1.5 x 10^{7} kelvins Changeover temperature from the proton-proton chain to the CNO cycle 2.7 x 10^{7} kelvins Center of a 5 solar mass star 5 x 10^{7} kelvins Typical gas temperature in a cluster of galaxies 1 x 10^{8} kelvins Typical cataclysmic variable accretion column shock temperature 3 x 10^{8} kelvins Center of a supernova 4 x 10^{8} kelvins Characteristic temperature for electron-positron pair production 4 x 10^{8} kelvins Minimum primordial nucleosynthesis temperature 5 x 10^{8} kelvins Inner accretion disc temperature of Cyg X-1 7 x 10^{8} kelvins Thermal electrons become relativistic 1 x 10^{9} kelvins Maximum primordial nucleosynthesis temperature 1 x 10^{9} kelvins Rough superconductivity critical temperature in a neutron star 1 x 10^{10} kelvins Rough plasma pair catastrophe temperature 3 x 10^{15} kelvins Rough electroweak unification temperature 7 x 10^{-13} N m^{-2} Typical gas pressure in a cluster of galaxies 5 x 10^{-12} N m^{-2} Pressure in the best vacuum achieved on Earth 5 x 10^{-6} N m^{-2} Solar radiation pressure at the Earth 1 x 10^{-5} N m^{-2} Pressure of a sound wave at the human threshold of hearing 0.2 N m^{-2} Solar radiation pressure at the surface of the Sun 30 N m^{-2} Pressure of a sound wave at the human threshold of pain 1 x 10^{4} N m^{-2} Mean human arterial blood overpressure 1.5 x 10^{4} N m^{-2} Standing person 1 x 10^{5} N m^{-2} Typical atmospheric pressure 1.5 x 10^{6} N m^{-2} High pressure bicycle tire 2 x 10^{7} N m^{-2} Typical scuba tank pressure 9 x 10^{7} N m^{-2} Peak pressure of a fist on concrete during a karate strike 1.1 x 10^{8} N m^{-2} Pressure at the bottom of the Marianas trench 6 x 10^{9} N m^{-2} Pressure needed for the natural crystalization of diamonds 1 x 10^{10} N m^{-2} Conventional high pressure laboratory press 2 x 10^{11} N m^{-2} Peak pressure from a diamond anvil pressure cell 5 x 10^{11} N m^{-2} Central pressure of the Earth 4 x 10^{12} N m^{-2} Central pressure of Jupiter 2 x 10^{13} N m^{-2} Radiation pressure at the center of the Sun 2.7 x 10^{16} N m^{-2} Central pressure of the Sun 1 x 10^{23} N m^{-2} Typical central pressure of a white dwarf 1 x 10^{34} N m^{-2} Typical central pressure of a neutron star 1 x 10^{-12} W m^{-2} Threshold of hearing (0 dB) 1 x 10^{-11} W m^{-2} Rustle of leaves (10 dB) 1 x 10^{-10} W m^{-2} Quiet whisper (20 dB) 1 x 10^{-9} W m^{-2} Soft music (30 dB) 3 x 10^{-8} W m^{-2} Average residence (45 dB) 1 x 10^{-6} W m^{-2} Background music (60 dB) 3 x 10^{-6} W m^{-2} Ordinary conversation at 0.5 meters (65 dB) 1 x 10^{-5} W m^{-2} Busy street traffic (70 dB) 3 x 10^{-5} W m^{-2} Typical factory (75 dB) 1 x 10^{-3} W m^{-2} Rough boundary of unsafe sound levels (90 dB) 1 x 10^{-2} W m^{-2} Lawn mower (100 dB) 1 W m^{-2} Loud rock music concert (120 dB) 10 W m^{-2} Threshold of pain (130 dB) 100 W m^{-2} Jet plane at 30 meters (140 dB) 9.128 x 10^{-35} kg m^2 s^{-1} Magnitude of the electron spin angular momentum 1.054 x 10^{-34} kg m^2 s^{-1} Planck angular momentum 3 x 10^{12} kg m^2 s^{-1} Rough angular momentum of an artificial satellite 5.9 x 10^{33} kg m^2 s^{-1} Earth rotational angular momentum 1.7 x 10^{41} kg m^2 s^{-1} Sun rotational angular momentum 3.1 x 10^{43} kg m^2 s^{-1} Total angular momentum of our solar system 2 x 10^{55} kg m^2 s^{-1} Angular momentum of the Sun around the center of the Milky Way 4 x 10^{66} kg m^2 s^{-1} Rough total angular momentum of the Milky Way 1 x 10^{-12} tesla Typical magnetic field needed for good radio reception 5 x 10^{-10} tesla Typical magnetic field strength in the local interstellar medium 1 x 10^{-9} tesla Typical magnetic field strength in a radio lobe 1 x 10^{-8} tesla Typical magnetic field strength in the central 300 parsecs of the Milky Way 5 x 10^{-8} tesla Magnetic field in the Crab Nebula 1 x 10^{-7} tesla Magnetic field in The Arc at the Milky Way center 1 x 10^{-6} tesla Typical magnetic field from a hand held cordless phone 3 x 10^{-5} tesla Magnetic field at Earth's surface 1 x 10^{-4} tesla Magnetic field near Sun's pole 4 x 10^{-4} tesla Magnetic field at Jupiter's cloud tops 0.1 tesla Ap star magnetic field 0.2 tesla Sunspot magnetic field 1 tesla Typical medical NMR magnetic field 2 tesla Magnetic field felt by the electron in a n=1 hydrogen atom 12 tesla Typical magnetic field used in high resolution NMR spectroscopy 25 tesla Powerful superconducting/normal hybrid magnet 1 x 10^{8} tesla Typical single pulsar dipole magnetic field strength 1 x 10^{4} amperes Peak lightning bolt current 5 x 10^{6} amperes Current along Io's flux tube 3 x 10^{8} volts Typical potential difference across a lightning bolt 3 x 10^{6} volts m^{-1} Electrical discharge field in air with ions 1 x 10^{12} volts m^{-1} Typical electric field at the surface of a pulsar 1 x 10^{19} volts m^{-1} QED pair production electric field limit 440 bits Spiegelman monster genome 18000 bits Q_beta virus genome 32000 bits Single spaced typed page 6.6 x 10^{5} bits Uncompressed ASCII version of _Lysistrata_ 4.36 x 10^{6} bits C. elegans nematode chromosome III --- longest contiguous piece of DNA sequenced 6 x 10^{6} bits E. Coli genome 6.3 x 10^{6} bits Uncompressed ASCII version of _A Tale of Two Cities_ 1 x 10^{9} bits Microcomputer hard drive 2.5 x 10^{9} bits Twenty volume edition of the Oxford English Dictionary on CD-ROM 7 x 10^{9} bits MACHO project data intake per night 9 x 10^{9} bits Human genome 8 x 10^{10} bits Sloan Digital Sky Survey spectral database 2 x 10^{11} bits International Halley watch database 5 x 10^{11} bits VCR tape 1 x 10^{12} bits Speed reading for 80 years with perfect memory 8.8 x 10^{12} bits HST archive size in mid-1994 9 x 10^{12} bits VLA FIRST Survey data set 2 x 10^{13} bits Digitized new Palomar sky survey 5 x 10^{13} bits Sloan Digital Sky Survey 0.4 arcsecond pixel map 8 x 10^{13} bits NSF backbone traffic in March 1994 3 x 10^{16} bits HDTV for 80 years with perfect memory 200 bits s^{-1} Typical reading and talking rate 500 bits s^{-1} Fast speed reading rate 24 000 bits s^{-1} Hipparcos satellite data acquisition rate 56 000 bits s^{-1} Typical Internet link 1 x 10^{5} bits s^{-1} High quality audio 1.4 x 10^{5} bits s^{-1} HST archive mean growth rate 1 x 10^{7} bits s^{-1} Xerox Ethernet 1 x 10^{7} bits s^{-1} HDTV bit rate after compression 4.5 x 10^{7} bits s^{-1} Internet backbone T3 link 6 x 10^{7} bits s^{-1} Sloan Digital Sky Survey data acquisition rate 3 x 10^{10} bits s^{-1} Soliton optical fiber information transmission rate 2 x 10^{15} bits s^{-1} Sexual reproduction genetic information transmission rate 2 x 10^{5} 1994 USA dollars Vancouver liquid mercury mirror telescope 1.5 x 10^{7} 1994 USA dollars Development and construction cost of the Giant Meterwave Radio Telescope near Pune, India 2.9 x 10^{7} 1994 USA dollars Total predicted cost of the Sloan Digital Sky Survey 5.5 x 10^{7} 1994 USA dollars Development, construction, and launch cost of the Clementine I spacecraft 8.5 x 10^{7} 1994 USA dollars VLBA development and construction cost 9 x 10^{7} 1994 USA dollars Development and construction cost of the Keck telescope 1 x 10^{8} 1994 USA dollars Development and construction cost of the ASCA X-ray satellite 1.5 x 10^{8} 1994 USA dollars Rough cost of a European Ariane rocket launch 2 x 10^{8} 1994 USA dollars Development and construction cost of the VLA 9 x 10^{8} 1994 USA dollars Development, construction, and launch cost of the Magellan probe 9.8 x 10^{8} 1994 USA dollars Development, construction, and launch cost of the Mars Observer spacecraft 1.5 x 10^{9} 1994 USA dollars Planned total cost of the AXAF X-ray mission 1.8 x 10^{9} 1994 USA dollars Amount of food stamp fraud in the USA in 1993 3.5 x 10^{9} 1994 USA dollars Planned total cost of the Cassini spacecraft 3.8 x 10^{9} 1994 USA dollars Microsoft revenue in 1993 1.3 x 10^{10} 1994 USA dollars Lockheed revenue in 1993 1.4 x 10^{10} 1994 USA dollars NASA planned 1995 budget 2.8 x 10^{10} 1994 USA dollars Planned cost for the space station 2.6 x 10^{11} 1994 USA dollars United States 1994 military spending 2.6 x 10^{11} 1994 USA dollars United States 1994 predicted defecit 1.3 x 10^{12} 1994 USA dollars United States 1994 tax receipts 1.5 x 10^{12} 1994 USA dollars United States 1994 federal government spending 4.4 x 10^{12} 1994 USA dollars United States 1994 national debt 0.004 Black velvet optical light albedo 0.012 Black cloth optical light albedo 0.04 Halley's comet optical light albedo 0.068 Moon optical light albedo 0.14 Mars optical light albedo 0.40 Earth optical light albedo 0.80 White paper optical light albedo 0.85 Venus optical light albedo 1 x 10^{-10} pc^{-3} Space density of X-ray binaries in the Milky Way 5 x 10^{-7} pc^{-3} Space density of pulsars in the solar neighborhood 3 x 10^{-6} pc^{-3} Space density of cataclysmic variables in the solar neighborhood 0.1 pc^{-3} Space density of main sequence stars in the solar neighborhood 1 x 10^{-9} Mpc^{-3} Ultraluminous IRAS galaxies 1 x 10^{-9} Mpc^{-3} Quasars 1 x 10^{-7} Mpc^{-3} QSOs 1 x 10^{-7} Mpc^{-3} FR II radio galaxies (edge-brightened) 5 x 10^{-6} Mpc^{-3} FR I radio galaxies (not edge-brightened) 1 x 10^{-4} Mpc^{-3} Seyfert galaxies 0.1 Mpc^{-3} Field galaxies 0.6 Mpc^{-3} Group galaxies -26.8 V apparent magnitude of the Sun -12.5 V apparent magnitude of the full Moon -1.5 V apparent magnitude of Sirius 0.1 V apparent magnitude of the LMC 0.5 V apparent magnitude of Betelgeuse 3.4 V apparent magnitude of M31 10.5 V apparent magnitude of the z=0.00363 Seyfert 2 NGC 1068 11.6 V apparent magnitude of the z=0.00170 H II region galaxy NGC 5408 12.8 V apparent magnitude of the z=0.158 quasar 3C273 13.6 V apparent magnitude of the z=0.0167 Seyfert 1 NGC 7469 15.3 V apparent magnitude of the z=0.239 quasar PG 0953+414 (ApJ 435, L12) 19.55 V apparent magnitude of the z=3.67 quasar DHM 0054-284 25.5 V apparent magnitude of a typical Cepheid in M100 (ApJ 435, L33) -27.5 M_V of the z=0.158 quasar 3C273 -24.1 M_V of the z=0.239 quasar PG 0953+414 (ApJ 435, L12) -21.1 M_V of M31 -21.0 M_V of a typical Seyfert host galaxy -19.5 M_V limit on the host galaxy of the z=0.239 quasar PG 0953+414 (ApJ 435, L12) -18.5 M_V of the LMC -6.0 M_V of Betelgeuse 4.4 M_V of the most luminous star in Alpha Centauri 4.79 M_V of the Sun Note: I assume an inflationary Omega_0=1.0 dust-filled Friedmann-Robertson-Walker universe with H_0=50 km s^{-1} Mpc^{-1} = 1.62 x 10^{-18} s^{-1} for all calculations. Space densities are given for ``here and now.''