Physics and Astronomical Constants and Errata
Physics Constants and Errata | Astronomical Constants and Errata
Written: 1998.08.01
Last Revised: 1998.08.29
Physics Constants and Errata
SI Units (fundamental)
|
Length |
m (metre) |
|
Mass |
kg (kilogram) |
|
Time |
s (second) |
|
Electrical Current |
A (ampere) |
|
Thermodynamic Temperature |
K (kelvin) |
|
Amount of matter |
mol (mole) |
SI Units (derived)
|
Area |
m² |
|
Volume |
m³ |
|
Frequency |
Hz (hertz, 1/s) |
|
Density |
kg/m³ |
|
Speed, Velocity |
v (m/s) |
|
Angular Velocity |
v (rad/s) |
|
Acceleration |
a (m/s²) |
|
Angular Acceleration |
a (rad/s²) |
|
Force |
N (newton, kg·m/s²) |
|
Pressure |
Pa (pascal, N/m²) |
|
Work, Energy |
J (joule, N·m) |
|
Power |
W (watt, N·m/s) |
|
Specific Heat Capacity |
cp (J/(kg·K)) |
|
Thermal Conductivity |
k (W/(m·K)) |
|
Electrical potential difference |
V (volt, W/A) |
|
Magnetic flux |
Wb (weber, V·s) |
|
Magnetic flux density |
T (tesla, Wb/m²) |
|
Unified Atomic Mass Unit |
u (1.660565E-27 kg) |
|
Electron-volt |
eV (1.602E-19 J) |
SI Prefixes
|
E (exa) |
1018 |
|
P (peta) |
1015 |
|
T (tera) |
1012 |
|
G (giga) |
109 |
|
M (mega) |
106 |
|
k (kilo) |
103 |
|
iso |
100 |
|
m (milli) |
10-3 |
|
m (micro) |
10-6 |
|
n (nano) |
10-9 |
|
p (pico) |
10-12 |
|
f (femto) |
10-15 |
|
a (atto) |
10-18 |
- Physics Constants
- Speed of light in vacuum c = 3E8 m/s
- Electron rest mass me = 5.49E-4 u
- Neutron rest mass mn = 1.0087 u
- Proton rest mass mp = 1.0072 u
- Hydrogen atom rest mass m1H = 1.0078 u
- Deuterium atom rest mass m2H = 2.0141 u
- Carbon atom rest mass m1C = 12.0000 u (exact; 1u is defined as 1/12 the mass of Carbon-12)
- Universal gas constant R = 8.31 J/mol·K
- Avogadro constant NA = 6.02E23 atoms/mol
- Stefan-Boltzmann constant s = 5.67E-8 W/(m²·K4)
- Gravitational constant G = 6.6726E-11 m³/(s²·kg)
- Bohr radius rB (hydrogen atom radius) = 5.29E-11 m
- Proton radius = 1.2E-15 m
- Proton magnetic moment mp = 1.41E-26 J/T
- Light-year = 9.46E15 m
- Planck constant = 6.626E-34 J·s
- Mass Density
- White dwarf star core ~ 1010 kg/m³
- Uranium nucleus ~ 3·1017 kg/m³
- Neutron star core ~ 1017 to 1018 kg/m³
- Black hole ~ 1019 kg/m³
- Energy Density (at 100% efficiency)
- Matter/antimatter annihilation = 9E16 J/kg
- Deuterium fusion = 6.2E14 J/kg
- Uranium-235 fission = 8.9E13 J/kg
- Hydrogen burning = 1.2E8 J/kg
- Methane gas burning = 5.0E7 J/kg
- Coal burning ~ 2.3E7 J/kg (depending on grade of coal)
- TNT detonation = 4.2E6 J/kg
- Power Intensities
- Power intensity at surface of Sun ~ 6E7 W/m²
- Power intensity of oxy-acetylene torch ~ 1E7 W/m²
- Power intensity of largest modern lasers built to date ~ 1E19 W/m²
- Temperatures
- Laboratory or fusion reactor plasma = 5E7 K
- Shock wave in atmosphere at Mach 20 = 2.5E4 K
- Luminous nebulae = 1E4 K
- Freezing temperature of water (0°C) = 273.15 K
- Specific Heats
- Aluminum = 960 J/kg·K
- Carbon (graphite) = 710 J/kg·K
- Iron = 420 J/kg·K
- Air = 994 J/kg·K
- Hydrogen = 14200 J/kg·K
- Pure water = 4180 J/kg·K
- Miscellaneous
- Energy required to ionize hydrogen = 13.58 eV/atom (1.3 GJ/kg)
- Energy required to split deuterium nuclei into neutrons and protons = 2.2 MeV/atom (105 TJ/kg)
Astronomical Constants and Errata
- The Milky Way Galaxy
- Mass ~ 2.2E41 kg
- Radius ~ 50,000 light years
- Number of stars ~ 100 billion
- Density of interstellar space ~ 1E-18 to 1E-21 kg/m³
- The Sun (Sol)
- Radius = 6.96E8 m
- Mass = 1.989E30 kg
- Surface temp = 5800 K
- Surface temp = 3800 K in sunspots
- Core density = 1.6E5 kg/m³
- Core temp = 15.6 million
- Corona temp ~ 1 million K
- Power output = 3.827E26 W
- Orbital radius around the centre of the galaxy ~ 3E20 m
- The Earth
- Radius = 6.371E6 m
- Depth of crust = 40 km
- Depth of mantle = 2700 km
- Mass = 5.974E24 kg
- Core density = 9.5E3 kg/m³
- Crust density = 2.8E3 kg/m³
- Mass of ocean water ~ 1.4E21 kg
- Orbital radius around Sol = 149.6 million km (1 AU)
- The Moon
- Radius = 1.738E6 m
- Mass = 7.348E22 kg
- Orbital radius around Earth = 382,000 km