The trapping of particles by magnetic fields was first studied by Kristian Birkeland in Norway, starting around 1895. ... Poincare managed to solve the motion of charged particles near an isolated magnetic pole, showing that they spiraled around field lines and that they were repelled from regions of strong field. ... A more realistic problem, of more interest to Birkeland, was particle motion near a compact bar magnet or "dipole", which better approximated the field of the Earth or of his terrella. ...

... Listed below are questions submitted by users of "The Exploration of the Earth's Magnetosphere" and the answers given to them. ... The ones included below are either of the sort that keeps coming up again and again--the danger of solar eruptions, the reversal of the Earth's magnetic field, etc.-- or else the answers make a special point, going into extra details which might interest other users. ... Radiation Belts and Manned Space Flight . ... Capturing the Energy of the Solar Wind . ...

Comets necessarily obey the same physical laws as every other object. ... If one considers only two bodies -- either the Sun and a planet, or the Sun and a comet -- the smaller body appears to follow an elliptical path or orbit about the Sun, which is at one focus of the ellipse. ... Another quantity that is conserved is called angular momentum. ... Comets simply are bodies which in general have more angular momentum per unit mass than do planets and therefore move in more elongated orbits. ...