**Chapter 31. List of symbols**

18th December 2017 by Dr Helen Klus

**31.0.1 Numerical Constants**

c |
Speed of light = 299,792,458 m/s (first used in Chapter 7) |

e |
Elementary charge = 1.602×10^{-19} C (to 3dp) (first used in Chapter 13) |

G |
Gravitational constant = 6.674×10^{-11} m^{3} kg^{-1} s^{-2} (to 3dp) (first used in Chapter 5) |

H_{0} |
Hubble parameter = 67.8 km s^{-1} Mpc^{-1} (to 1dp) (first used in Chapter 9) |

h |
Planck’s constant = 6.626×10^{-34} Js (to 3 dp) (first used in Chapter 7) |

ħ |
ħ = h2π, where h is Planck’s constant (first used in Chapter 13) |

m_{e} |
Electron mass = 9.109×10^{-31} kg (to 3dp) (first used in Chapter 13) |

π |
π = CD = 3.142 (to 3 dp), where C is the circumference of a circle, C = 2πr, and D is the diameter of a circle, D = 2r (first used in Chapter 2) |

**31.0.2 Other symbols**

A |
Surface area (first used in Chapter 4) |

a |
Acceleration (first used in Chapter 3) |

a_{c} |
Centripetal acceleration (first used in Chapter 3) |

B |
Magnetic field (first used in Chapter 13) |

C |
Circumference (first used in Chapter 3) |

D |
Diameter (first used in Chapter 7) |

d |
Distance (first used in Chapter 3) |

E |
Total energy (first used in Chapter 4) |

e_{rel} |
Relativistic energy (first used in Chapter 7) |

e_{0} |
Rest energy (first used in Chapter 7) |

E_{cyc} |
Cyclotron energy (first used in Chapter 13) |

F |
Force (first used in Chapter 4) |

F_{c} |
Centripetal force (first used in Chapter 5) |

GPE |
Gravitational potential energy (first used in Chapter 4) |

G_{μν} |
Einstein tensor (first used in Chapter 8) |

g_{μν} |
Metric tensor for Minkowski space (first used in Chapter 8) |

g |
Acceleration due to gravity (first used in Chapter 2) |

HV |
Heating value (first used in Chapter 6) |

h |
Height (first used in Chapter 4) |

KE |
Kinetic energy (first used in Chapter 4) |

L |
Angular momentum (first used in Chapter 4) |

L |
Luminosity (first used in Chapter 6) |

ℓ |
Length (first used in Chapter 2) |

ℓ_{rel} |
Relativistic length (first used in Chapter 7) |

m |
Mass (first used in Chapter 4) |

m_{1} |
Mass of the less massive object (first used in Chapter 5) |

m_{2} |
Mass of the more massive object (first used in Chapter 5) |

n |
Shell number (first used in Chapter 13) |

P |
Period (first used in Chapter 2) |

P_{r} |
Pressure (first used in Chapter 4) |

p |
Momentum (first used in Chapter 4) |

R_{com} |
Rate of combustion (first used in Chapter 6) |

R_{μν} |
Ricci tensor (first used in Chapter 8) |

r |
Radius (first used in Chapter 3) |

r_{Sch} |
Schwarzschild radius (first used in Chapter 14) |

T_{μν} |
Energy-momentum tensor (first used in Chapter 8) |

t |
Time (first used in Chapter 3) |

t_{rel} |
Relativistic time (first used in Chapter 7) |

V |
Volume (first used in Chapter 4) |

v |
Velocity (first used in Chapter 3) |

v_{esc} |
Escape velocity (first used in Chapter 14) |

W |
Work (first used in Chapter 4) |

x |
Position (first used in Chapter 3) |

γ |
Lorentz factor (first used in Chapter 7) |

Δ | ‘Change in’ (first used in Chapter 3) |

θ |
Angular size (first used in Chapter 30) |

λ |
Wavelength (first used in Chapter 7) |

ν |
Frequency (first used in Chapter 7) |

ρ |
Density (first used in Chapter 4) |

τ |
Torque (first used in Chapter 4) |

Ω | Energy density (first used in Chapter 9) |

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### How We Came to Know the Cosmos: Space & Time

**I Pre 20th Century theories**

4. Force, Momentum, and Energy

**II 20th Century discoveries**

7. Einstein’s theory of Special Relativity

8. Einstein’s theory of General Relativity

12. Red Giants and White Dwarfs

13. Supergiants, Supernova, and Neutron Stars

**III Missions to planets**

**IV Beyond the planets**

26. The Kuiper Belt and the Oort Cloud

27. The Pioneer and Voyager Missions

29. The Search for Alien Life in the Universe

**V List of symbols**