... One of the most obvious features of the plasma state is the rich variety of wave motions which plasmas can support. ... Some important wave parameters in general are: . ... The way the dispersion relation is calculated depends on the adopted plasma theory , which also determines the available wave modes. ... the more complicated the medium is, the more wave modes it support (we cannot have, e.g., ion plasma waves if ion motion is neglected in the first place, no matter how hot plasma is considered!)...

... One useful consequence of Newton's 3rd law is the conservation of momentum, as is shown by analyzing the recoil of a cannon. The example shows that while the gun and shell get equal amounts of momentum, by far most of the energy is given to the shell. Here mechanical energy is not conserved--some ends up as heat. ... We have discussed so far mass, velocity, acceleration, force and energy, and the way Newton's laws tie them together. ... momentum P = mass times velocity . ... Total mass . ...

Phoebe . Saturn IX . Phoebe [FEE-bee] is the last of the known satellites of Saturn, at a distance of 12.952 million kilometers (8 million miles). Phoebe orbits Saturn in a retrograde direction (opposite to the direction of the other satellites' orbits) in a plane much closer to the ecliptic than to Saturn's equatorial plane. ... Scientists believe that Phoebe may be a captured asteroid with a composition unmodified since the time it was formed in the outer Solar System . ...

Cosmic Research, Vol. 42, No. 5, 2004, pp. 435­488. Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 5, 2004, pp. 453­508. Original Russian Text Copyright © 2004 by Veselovsky, Panasyuk, Avdyushin, Bazilevskaya, Belov, Bogachev, Bogod, Bogomolov, Bothmer, Boyarchuk, Vashenyuk, Vlasov, Gnezdilov, Gorgutsa, Grechnev, Denisov, Dmitriev, Dryer, Yermolaev, Eroshenko, Zherebtsov, Zhitnik, Zhukov, Zastenker, Zelenyi, Zeldovich, Ivanov-Kholodnyi, Ignat'ev, Ishkov, Kolomiytsev, Krasheninnikov, Kudela,