http://en.wikipedia.org/wiki/Bussard_ramjet
The *Bussard ramjet* is a theoretical method of spacecraft propulsion<http://en.wikipedia.org/wiki/Spacecraft_propulsion>proposed in 1960 by the physicist Robert W. Bussard <http://en.wikipedia.org/wiki/Robert_W._Bussard>, popularized by Poul Anderson <http://en.wikipedia.org/wiki/Poul_Anderson>'s novel *Tau Zero <http://en.wikipedia.org/wiki/Tau_Zero>*, Larry Niven<http://en.wikipedia.org/wiki/Larry_Niven>in his Known Space <http://en.wikipedia.org/wiki/Known_Space> series of books, Vernor Vinge <http://en.wikipedia.org/wiki/Vernor_Vinge> in his Zones of Thought<http://en.wikipedia.org/wiki/Zones_of_Thought>series, and referred to by Carl Sagan <http://en.wikipedia.org/wiki/Carl_Sagan> in the television<http://en.wikipedia.org/wiki/Television>series and book <http://en.wikipedia.org/wiki/Cosmos_(book)> *Cosmos <http://en.wikipedia.org/wiki/Cosmos:_A_Personal_Voyage>*. Bussard proposed a ramjet <http://en.wikipedia.org/wiki/Ramjet> variant of a fusion rocket <http://en.wikipedia.org/wiki/Fusion_rocket> capable of reasonable interstellar spaceflight, using enormous electromagnetic fields (ranging from kilometers to many thousands of kilometers in diameter) as a ram scoop to collect and compress hydrogen<http://en.wikipedia.org/wiki/Hydrogen>from the interstellar medium <http://en.wikipedia.org/wiki/Interstellar_medium>. High speeds force the reactive mass into a progressively constricted magnetic field, compressing it until thermonuclear fusion occurs. The magnetic field then directs the energy as rocket <http://en.wikipedia.org/wiki/Rocket> exhaust opposite to the intended direction of travel, thereby accelerating the vessel. When this hydrogen collection strategy is integrated with cold fusion, there is no limitation on the amount of energy that that be applied to a Ram Jet propulsion ship. The conceptual implications of magnetically induced cold fusion is currently beyond the imaginations of most people at this early juncture. On Sat, Jan 11, 2014 at 7:20 PM, David L Babcock <[email protected]> wrote: > The bad news negates itself: > > Considering C of E, a miss-aimed craft could not apply more energy to a > planet than was originally applied to the craft to bring it up to speed. A > continent-melting crash requires that more than a continent-melting supply > of fuel has been applied to/used by the craft. > > Another consideration: The craft has to carry with it a similar amount of > energy, stored, to use for deceleration. And twice that again, to come home. > > If you account for different depths of gravity wells, it comes out > different, but not much. We were talking about speeds up towards light, no? > > So conservation of energy, having obliterated CF (a little gratuitous > snark), now moves on to ruin our dreams of visiting other stars. > > Dave B. > > > On 1/10/2014 5:14 PM, David Roberson wrote: > > That is amazing! -snip- > > I have never considered how much damage a space craft traveling near light > speed would inflict, but apparently it would be bad news. > > Dave > > > >
