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
3 x 10^{53} joules Total AGN outburst energy of RBS 797
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
1 x 10^{55} joules Total Energy released in MS 0735.6+7421 Cluster
AGN outburst
5 x 10^{57} joules Typical gravitational binding energy of
a cluster of galaxies
1 x 10^{58} joules Total Mass Energy of Milky Way's Luminous mass
1 x 10^{68} joules Total Mass-energy content of our Observable Universe
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 x 10^{38} watts Rough luminosity of the quasar 3C273
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
2 x 10^{39} watts Rough luminosity of the z=2.286 ultraluminous IRAS galaxy IRAS F10214+4724
3 x 10^{39} watts 3C 454.3 Peak True luminosity
1 x 10^{40} watts Typical quasar luminosity
1 x 10^{42} watts Rough luminosity of a typical Long gamma-ray burst
1 x 10^{43} watts Rough luminosity of GRB 990123 or GRB 990123
1 x 10^{44} watts Rough luminosity of GRB 090926A or GRB 070125 or GRB 080721
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)
-33.0 M_B of the quasar BR1202-07
-31.7 M_B of the quasar S5 0014+81
-30.0 M_B of the quasar SDSS J085543.40-001517.7
-30.5 M_B of the quasar APM 08279+5255
-26.4 M_B 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
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
3 x 10^{53} joules Total AGN outburst energy of RBS 797
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
1 x 10^{55} joules Total Energy released in MS 0735.6+7421 Cluster
AGN outburst
5 x 10^{57} joules Typical gravitational binding energy of
a cluster of galaxies
1 x 10^{58} joules Total Mass Energy of Milky Way's Luminous mass
1 x 10^{68} joules Total Mass-energy content of our Observable Universe
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 x 10^{38} watts Rough luminosity of the quasar 3C273
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
2 x 10^{39} watts Rough luminosity of the z=2.286 ultraluminous IRAS galaxy IRAS F10214+4724
3 x 10^{39} watts 3C 454.3 Peak True luminosity
1 x 10^{40} watts Typical quasar luminosity
1 x 10^{42} watts Rough luminosity of a typical Long gamma-ray burst
1 x 10^{43} watts Rough luminosity of GRB 990123 or GRB 990123
1 x 10^{44} watts Rough luminosity of GRB 090926A or GRB 070125 or GRB 080721
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)
-33.0 M_B of the quasar BR1202-07
-31.7 M_B of the quasar S5 0014+81
-30.0 M_B of the quasar SDSS J085543.40-001517.7
-30.5 M_B of the quasar APM 08279+5255
-26.4 M_B 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
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