Sidereal time

DAY (d). A unit of time, the exact definition of which is dependent upon which system of time measurement Is referred to, i.e., apparent solar time, mean solar time, universal time, apparent sidereal time, ephemera time, or atomic time. See Time. With exception of atomic time, the time base is referenced to rotation of the Earth. For general purposes, a day is considered tire period taken for 1 revolution of the Earth about its axis... 

The body s internal molecular timekeeper, known as the circadian clock, regulates cycles of sleep and wakefulness. When it is out of sync, it can cause disorders such as jet lag and depression. Conventional time-of-day measurements are based on the changing position of the Sun in the sky, but shifts in the positions of stars can also be used to define a kind of time known as sidereal time. One sidereal day lasts a few minutes less than one solar day. 

The nominal GPS constellation is composed of 24 satellites in six orbital planes, (four sateUites in each plane). The satellites operate in circular 20,200-km altitude (26,570 km radius) orbits at an inclination angle of 55° and with a 12-h period. The position is therefore the same at the same sidereal time each day, that is, the satellites appear four minutes earUer each day. 

The earth spins around its instantaneous spin axis at a more or less constant angular velocity of once per sidereal day —sidereal time scale is taken with respect to fixed stars, which is different from the solar time scale, taken with respect to the sun. This spin gives rise to a centrifugal force that acts on each and every particle within or bound with the earth. A particle, or a body, which is not bound with the earth, such as an earth satellite, is not subject to the centrifugal force. This force is given by the following equation ... 

Shutdowns, as well as startups, require eare and attention. Shutdown of a unit, whieh has been operating in a humid atmosphere, ean result in eon-siderable eondensation and subsequent rusting of the gears, shaft journals, and housing in a very short time. When water eontaets elean steel, it begins to eteh the steel immediately. When shutdowns in sueh eonditions are neeessary, provisions to prevent eondensation must be furnished. 

The putrefaction of metallic seed must, like that of animal and vegetable seed, take place through the cooperation of the four elements. I have already explained that the elements themselves are not the seed. But it ought by this time to be clear to you that the metallic seed which was produced by the combined operation of heavenly, sidereal, and elementary essences, and reduced into bodily form, must, in due course, be corrupted and putrefied by means of the elements. 

Think most diligently about this often bear in mind, observe and comprehend, that all minerals and metals together, in the same time, and after the same fashion, and of one and the same principal matter, are produced and generated. That matter is no other than a mere vapour, which is extracted from the elementary earth by the superior stars, or by a sidereal distillation of the macrocosm which sidereal hot infusion, with an airy sulphurous property, descending upon inferiors, so acts and operates as that there is implanted, spiritually and invisibly, a certain power and virtue in those metals and minerals which fume, moreover, resolves in the earth into a certain water, wherefrom all metals are thenceforth generated... 

In calculating the pressure at the point, at Xi < the time interval t, S i < i, should be consi-sidered. 

Men can do nothing without the make-believe of a beginning. Even Science, the strict measurer, is obliged to start with a make-believe unit, and must fix on a point in the stars unceasing journey when his sidereal clock shall pretend that time is Nought. 

Abstract. Following a suggestion of Kostelecky et al. we have evaluated a test of CPT and Lorentz invariance from the microwave spectrosopy of muonium. Precise measurements have been reported for the transition frequencies U12 and 1/34 for ground state muonium in a magnetic field H of 1.7 T, both of which involve principally muon spin flip. These frequencies depend on both the hyperfine interaction and Zeeman effect. Hamiltonian terms beyond the standard model which violate CPT and Lorentz invariance would contribute shifts <5 12 and <5 34. The nonstandard theory indicates that P12 and 34 should oscillate with the earth s sidereal frequency and that 5v 2 and <5 34 would be anticorrelated. We find no time dependence in m2 — vza at the level of 20 Hz, which is used to set an upper limit on the size of CPT and Lorentz violating parameters. 

However, the theory with CPT and Lorentz violation involves spatial components in a celestial frame of reference, and since the laboratory rotates with the earth, these spatial components vary with time, and consequently the experimentally observed 1/42 and P34 may oscillate about a mean value at the earth s sidereal frequency fi = 27t/23 hr 56 rn with amplitudes 81/42 and 81/34. No such signal would be obtained from the standard model. In the non-rotating celestial frame of reference with equatorial axes x, Y,Z where Z is oriented along the earth s rotational North Pole, an experimental constraint on 81/12 implies [4]... 

The result from muonium can be compared with some other tests of CPT violation based on this theory (Table 1). Another type of experiment listed in Table 1 is the search for a time variation during a sidereal day of a nuclear magnetic resonance signal[9]. The first such experiment was done on 7Li in which the... 

There is a comprehensive sense in this coincidence (with the accuracy of coefficients) of expressions that derive the quantities of entropy and information The entropy of a system and the information on the system are interrelated. One can consider the information to be identical to that difference between the maximal possible entropy of the system and the entropy actually inherent in the system at the moment of time under con sideration, or vice versa, entropy is identical to the information missing for the full system description. The latter becomes clear after the information on the system has been received. 

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