A search for correlation between Kpand the lunar phase

One of the first scientific activities seems to date from prehistory, namely, the search for correlation between the motion of heavenly bodies and almost any other observable phenomenon, ranging from political events to biological functions. This active field of endeavor has continued up to the present [e.g., Bigg, 1963]. This note differs somewhat, perhaps, from the genre in being an account of an unsuccessful search ; we report it here in the hopes of diverting attention and effort into more productive channels in accord with Bartels' [1963] recent analysis. Since it is now known that a solar wind of charged particles flows essentially radially outward from the sun and is apparently related to observed geomagnetic activity [Snyder et al., 1963], it might be thought that when a body is at or near inferior conjunction the solar wind flow will be disturbed and will, thereby, affect the geomagnetic observations. Whether the effect will be sensible or not is an entirely different matter. Figure 1 shows to scale the relative size and position of parameters expected to be important to any geomagnetic effects from the moon. Note that even though the moon's orbit is inclined to the plane of ecliptic, its wake, if any, should always sweep across the magnetosphere at new moon. Figure 1 suggests that any wake from the moon may be too weak by the time it reaches the magnetosphere to produce a perturbation sufficient to cause a significant geomagnetic effect. By means of a modified form of the superposed epoch analysis [Chree, 1912; Chapman and Bartels, 1940] based on the synodic lunar month, we are able to place quantitative limits on this intuitive argument.