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No. 71: Sep-Oct 1990

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WHAT'S ANOTHER DIPOLE OR TWO?

"Planetary exploration by deep space probes in recent years has shown that the dipole moment of some mag netized planets has a surprisingly large inclination angle with respect to the rotation axis. It is argued that the inclined dipole thus obtained may not be physically realistic. Applying the method we have developed for the source surface magnetic field of the sun (a spherical surface of 2.5 solar radii), it is suggested that the main dipole of the earth and the magnetized planets is actually axial (the magnetic moment is parallel or antiparallel to the rotation axis), and that two or three smaller dipoles near the core surface are responsible for the apparent inclination of the main dipole." (Akasofu, S-I., and Saito, T.; "Is the Earth"s Dipole Actually Inclined with Respect to Its Rotation Axis?" Eos, 71: 490, 1990.)

Comment. In SF#70, we see that the magnetic field of Uranus is inclined a whopping 60 to its axis of rotation. Can a few, small additional dipoles distort the main field so much? And just what are these small dipoles anyway -- physically and electrically?

From Science Frontiers #71, SEP-OCT 1990. 1990-2000 William R. Corliss