Category: Phenomena

A top-level category of Obscuripedia. The list below is believed complete, though membership – like everything here – is subject to revision.

• Bathybius haeckelii – A living slime said to carpet the Atlantic floor, described in 1868 from mud kept eleven years in alcohol. The alcohol had made it.
• Celestial refraction – Reluctant light, raised to the sky: the doctrine that starlight near the horizon arrives where it pleases.
• The CMB dipole – The warm side of the sky: a 3.4 millikelvin asymmetry caused entirely by our own motion, and used to calibrate the instruments that measure it.
• Curved visual space – The real finding that perceived space is not Euclidean: a fact about the observer, cited as one about the light, by papers that exempt the instrument.
• Dip of the horizon – The angle by which the sea horizon falls below eye level, growing as the square root of the observer's height: in every almanac, and shaped like a radius.
• Dunning–Kruger effect – The documented finding that confidence runs highest where competence runs lowest – the real-world law behind this encyclopedia's unit of conviction, the whect.
• Eclipse – Announced to the second, centuries ahead, on a named strip of ground. The one term that cannot be computed is how fast the Earth will be turning.
• Fata Morgana – Stacks a distant coast into towers, stretches a lighthouse into a column, hangs a ship above the sea. It cannot move any of them sideways.
• General relativity – A theory of gravitation containing no force of gravity, built out of the fact that a falling man feels nothing at all.
• Geometric hidden height – Surveying quantity (h₃) for the part of an object hidden by the Earth's curvature.
• Gravity – The weakest of the four forces and the worst-measured quantity in physics: sixteen laboratories have determined its constant and they do not agree.
• Kinematic and dynamic equivalence – Two claims about reference frames: the first true and never disputed, the second contested, the two offered as one.
• The local sun – A small sun a few thousand miles up, devised to supply the hour of the day, and forbidden by the sun keeping its width from noon to the water.
• Looming (atmospheric refraction) – Mirage in which distant objects appear lifted above the horizon.
• Luminiferous aether – The real, discredited 19th-century medium for light – abandoned by physics in 1887, and never by the Aetheric Concord.
• Min Min light – The light that follows travellers across western Queensland. Shown in 2003 to be a mirage of a car 300 km away, and still officially unexplained.
• Mirage – Not a trick of the mind: a real image of a real object, correctly formed, arriving from a direction the object is not in. It photographs, which settles it.
• Novaya Zemlya effect – The Sun seen weeks before it is due, guided round the curve of the Earth by an inversion. Recorded in 1597 and disbelieved for three centuries.
• Orbits – A fall that keeps missing. The space station drops 4.32 metres a second, and over the 7.66 km it covers meanwhile, its own orbit drops 4.32 metres.
• Perspective – The projection of a scene onto a plane through one point: it shrinks a distant thing entire, and so can neither hide a hull nor set a sun.
• The Pioneer anomaly – A sunward drift on both Pioneers that outlasted the missions and stayed unexplained for thirty years. It was waste heat: the craft were pushing themselves.
• Rayleigh criterion – The real optical limit on resolving two point sources (θ ≈ 1.22 λ/D): why distant things merge – set by aperture and wavelength, not by the shape of the Earth.
• Reluctant light – Discredited 19th-century doctrine that light arrives where it pleases.
• Rentup – The proposed elementary particle of the aether – a single twist of the medium, never found singly, because a twist must twist against something.
• The Sagnac effect – The fringe shift from sending light both ways round a rotating loop, offered as the disproof of relativity, and in fact a direct measurement of the relativity of simultaneity.
• Selenelion – The Sun and the totally eclipsed Moon seen at once, from opposite horizons, in a geometry that places them exactly opposite and therefore forbids it.
• Special relativity – Two postulates and their consequences, named after the wrong half of itself: not that everything is relative, but that the speed of light is not.
• Stellar aberration – The annual tilt of every star by the same 20.5 arcseconds, found by a man hunting parallax, and now cited against the motion that causes it.
• Stellar parallax – The annual shift demanded as proof of the Earth's motion in 1543, not found for 295 years, and there the whole time.
• Three-body problem – The problem of three bodies under mutual gravitation: no solution in closed form, and three centuries of correct predictions regardless.
• Vacuum – Defined by what is not in it, which makes it the one thing in physics described by a list. The list has been declared complete three times.
• Wave–particle duality – The finding that light and matter behave in ways the words wave and particle were built to keep apart. The difficulty is in the words.

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