Heavy elements such as the uranium used in generating nuclear power are extremely concentrated sources of energy. ... Space rockets require not just energy, but also mass , matter ejected backwards, of which nuclear fuel provides very little. The limiting factor in the operation of rockets is not a shortage of energy but the high temperature at which they operate. ... One possible loophole remains. ... Test model of "Orion," pro- . ... Next Stop: #32 Far-out Pathways to Space: Solar Sails . ...

... 32a. Solar Early Warning . Heavy elements such as the uranium used in generating nuclear power are extremely concentrated sources of energy. ... Space rockets require not just energy, but also mass , matter ejected backwards, of which nuclear fuel provides very little. ... One possible loophole remains. ... And yet... the "Orion" propulsion method could one day be the only practical way of protecting Earth from asteroid impact. ... Next Stop: #32 Far-out Pathways to Space: Solar Sails . ...

Sixty-five million years ago, about 70 percent of all species then living on Earth disappeared within a very short period. ... Paleontologists speculated and theorized for many years about what could have caused this mass extinction, known as the K-T event (Cretaceous-Tertiary Mass Extinction event). ... The Alvarez team suggested that the enhancement was the product of a huge asteroid impact. ... Sulfuric acid aerosols may have cooled Earth for years. ... Appendix C ...

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,