Pink Noise - Leonid Korogodski [64]
parsec
A unit of length in astronomy equal to about 30.857 trillion kilometers (approximately, 19 trillion miles), or 3.26 light years.
peacock tail
A kind of mast on magsail ships of almost any class.
See also magnetic sail.
phase transition
A change in the state of matter; for example, from liquid to solid or gas.
photonic network
A network in which signals are passed not by electric current in conducting wires but by photons (light) in waveguides. Photonic crystals, a kind of metamaterial, are used to control the motion of photons.
See also metamaterial and waveguide.
place cells
See hippocampus.
plasmatail
The part of a cosmic body’s plasmasphere where it extends away from the Sun, blown by the solar wind. Also known as magnetotail, somewhat inaccurately, since it is also possessed by planets that don’t generate their own magnetic field, not to mention comets.
plasmoid
A toroidal or round plasma structure that remains coherent over a substantial period of time; ball lightning, for example. Plasmoids are found in the planetary magnetospheres and are likely to exist at the centers of galaxies (in lieu of hypothetical black holes). Plasmoids are unstable, decaying into plasma jets.
polariton
A quasi-particle representing the coupling of a photon with an excited quantum state. The states in question are called plasmon, exciton, or phonon, depending on the frequency of photons they can couple with. Polaritons are used in photonics to capture and guide light.
See also photonic network, polaritonic cloak, and waveguide.
polaritonic cloak
A surface of metamaterial that can capture light and guide it (as polaritons) around the protected body to release the photons at the opposite side, thus turning it invisible. Note, however, that the invisibility effect cannot be achieved on all frequencies at the same time, nor from all directions.
Although it is usually referred to in popular science as plasmonic cloak, the excited quantum states that can couple with the photons (see the entry on polariton, above) needn’t necessarily be plasmons. Because the common term in all cases is polariton, the choice was made to call this device a polaritonic cloak in Pink Noise.
See also metamaterial and polariton.
pontine reticular formation
A part of the brain involved in regulating the sleep/awake cycle.
power needle
A kind of power generator in Pink Noise that draws power from the solar wind and also from dust devils drawn to it by the attractive force between parallel electric currents. Although extremely tall (but not as tall as a “space elevator”), they don’t have to be built on the equator, because their stability is strengthened by this force.
See also dust devil, flywheel, and solar wind.
prana [SANSKRIT: ]
Literally, “breath.” In Hinduism, prana is the vital energy, permeating the cosmos and sustaining all living beings.
prayer flags
In the Tibetan Buddhist worship, these are colorful pieces of fabric often found hanging on lines stretched along mountain trails.
prayer wheels
An element of Tibetan Buddhist worship. Spinning a prayer wheel is considered the equivalent of uttering a prayer.
pyramidal tract
A neuronal pathway that connects the neocortex and the spinal cord. Also known as the corticospinal tract.
Q
qhuqhumbela [Zulu]
A rhythmic, energetic Zulu dance with drums and handclaps as accompaniment.
R
raudram [SANSKRIT: ]
The rasa of fury in Indian art and aesthetics. A rasa is the emotional response evoked in the audience by the artist.
relativistic time dilation
The phenomenon of time passing differently to different observers in special relativity. The faster one moves relative to another, the slower is the passage of time to the former. At the speed of light in vacuum, time stops.
Rényi entropies
A family of physical quantities that generalize the concept of entropy, a measure of disorder in a system.
revenant
In folklore, an undead returning from the grave to seek revenge.
right-hand rule
If the palm is the plane of the