Twistors in TGD UniverseThis article was inspired by a longer paper "TGD view about McKay Correspondence, ADE Hierarchy, Inclusions of Hyperfinite Factors, and Twistors". I found it convenient to isolate the part of paper related to twistors. In twistor Grassmannian approach to N=4 SYM twistors are replaced with supertwistors and the extreme elegance of the description of various helicity states using twistor space wave functions suggests that supertwistors are realized at the level of M^{8} geometry. These supertwistors are realized at the level of momentum space. In TGD framework M^{8}H duality allows to geometrize the notion of supertwistor in the sense that different components of superfield correspond to components of superoctonion each of which corresponds to a spacetime surfaces satisfying minimal surface equations with string world sheets as singularities  this is geometric counterpart for masslessness. In TGD particles are massless in 8D sense and in general massive in 4D sense but 4D twistors are needed also now so that a modification of twistor approach is needed. The incidence relation for twistors suggests the replacement of the usual twistors with either noncommutative quantum twistors or with octotwistors. Quantum twistors could be associated with the spacetime level description of massive particles and octotwistors with the description at imbedding space level. A possible alternative interpretation of quantum spinors is in terms of quantum measurement theory with finite measurement resolution in which precise eigenstates as measurement outcomes are replaced with universal probability distributions defined by quantum group. This has also application in TGD inspired theory of consciousness. The outcome of octotwistor approach together with M^{8}H duality leads to a nice picture view about twistorial description of massive states based on quaternionic generalization of twistor (super)Grassmannian approach. A radically new view is that descriptions in terms of massive and massless states are alternative options, and correspond to two different alternative twistorial descriptions and leads to the interpretation of padic thermodynamics as completely universal massivation mechanism having nothing to do with dynamics. The basic problem of the ordinary twistor approach is that the states must be massless in 4D sense. In TGD framework particles would be massless in 8D sense. The meaning of 8D twistorialization at spacetime level is relatively well understood but at the level of momentum space the situation is not at all so clear.
