Energy and Human Ambitions on a Finite Planet, 2021a

422
Glossary
AC
alternating current. 77, 215
AER
Annual <strong>Energy</strong> Review. 102, 103, 105–107, 109, 170
alpha decay
4
(α) happens when a nucleus emits an alpha particle, otherwise known as a He nucleus. 243,
422, 435
alpha particle
4
(α) isa He (helium) nucleus, ejected from a larger nucleus in an alpha decay It therefore
consists of two protons <strong>and</strong> two neutrons. 243, 245, 422
Amp
(A) is short for Ampere. 77, 293, 422, 425
Ampere
(A, or Amp)istheSI unit of current, defined such that one Ampere is the same as one Coulomb
per second (1 A 1C/s). 77, 422
a.m.u.
atomic mass unit. 241, 246–248, 253, 254, 265, 376, 422, 432, 433, 435
Annual <strong>Energy</strong> Review
is compiled by the U.S. EIA, capturing energy use <strong>and</strong> trends for all sources <strong>and</strong> sectors [34].
102, 170, 422
Astronomical Unit
(AU) is a unit of distance, equal to the average Earth–Sun distance of 149.6 million kilometers
(1.496 × 10 11 m). 56, 422
asymmetric risk
describes a condition where given the choice to pursue action B for fear of some future condition
instead of the normal action A, the downside of being correct about the threat <strong>and</strong> not taking
action B is far more disastrous than being wrong about the threat <strong>and</strong> pursuing route B
unnecessarily. 345, 351
atomic mass unit
(a.m.u.) is defined so that a single neutral carbon atom, consisting of 6 protons, 6neutrons, <strong>and</strong>
6 electrons has exactly 12.00000 a.m.u. In other units, it is 931.4941 MeV or 1.66054 × 10 −27 kg.
This unit sometimes goes by the name: Dalton. 241, 376, 422, 433
AU
Astronomical Unit. 56, 206, 420, 422
Avogadro’s number
is N A 6.022 × 10 23 , pertaining to one mole of particles (e.g., atoms, molecules). 375, 376, 381,
433
b<strong>and</strong> gap
is the energy difference between the conduction b<strong>and</strong> <strong>and</strong> the valance b<strong>and</strong>, determining how
much energy is needed to promote an electron out of an atom <strong>and</strong> into conduction. 203, 204, 223
© 2021 T. W. Murphy, Jr.; Creative Commons Attribution-NonCommercial 4.0 International Lic.; Freely available at:
https://escholarship.org/uc/energy_ambitions.