[Madidus_Scientia]

How does the energy in a vacuum have to do with the fact that as you produce energy from a nuclear reactor you lose mass? You told me I was incorrect

[Mr. Scientist]

you where. You stated with a related compliance with litespeed that:

''Madidus_Scientia - You wrote: "You'd be creating mass by losing mass. The energy comes from the mass of the nuclear material." 

Very good, grasshopper! Energy can neither be created nor destroyed, it only changes form.''

You had obviously agreed on this no? Because if you are still doing to deny your mistake, i will cut myself from this conversation all-together.

[litespeed (OP)]

MS

I make no claim to understand the laws and exceptions to conservation of energy.  I simply point out I can create energy from mass in a reactor, consolidate some of that energy into electricity for my electro/magnetic linear accelerator.  The accelerator will then convert some of the electo/magnetic energy into 1) kinetic energy out the back of my starship as it expells protons; and 2) add some mass to the particles accelerated.

Even a small nuclear reactor could provide enough energy to propell my starship. The trick is to use as little mass as possible at the highest velocity possible out the back of the linear accelerator. We are talking very small amounts of accelerated mass needed for very long trips. As pointed out elsewhere, a single cosmic ray (mostly protons) traveling close to the speed of light arrive at earth with the same energy as a tennis ball at 100 mph.

IMH, a good enough reactor and a good enough accelerator could be operated for years by the number of protons in a single pack of cigarettes. Its not a matter of taking enough fuel with me; I have already chosen the size of my reactor. I just need to transfer the energy from the fuel in my reactor mass to kinetic energy out of my linear accelerator. The protons inserted into the accelerator are not fuel. 

A simple analog: the protons work just like bullets fired from a gun. You get rercoil. A very small bullet can give one HELL of a recoil if it is pushed out the barrel fast enough.

[hcm1955]

Maybe this question has already been answered but: Assuming two particles (X1 and X2) moving at relativistic velocities relative to each other.

      X1 --->
      |
      d
      |
<---X2


Is there some distance d and some velocity less than c where X1 and X2 will orbit each other?

The closer the bodies approach speed of light then the larger the force due to gravity (or the more space-time bends) hence the two bodies will move closer to each other.

Cheers,
Bert

[Atomic-S]

That is a remarkable concept: that as the speed of 2 bodies that normally would be thrown apart increases, eventually a point is reached where the mass increases overcome the centrifugal tendency and the bodies start drawing together again. (Nasa had better watch out: launchng a spacecraft to fast might cause it to be attracted back to the Earth and crash). Well, this remarkable hypothesis might possibly be true under some extreme conditions, although I still have a bit of a problem believing that the rate of mass increase could ever overtake the tendency toward centrifugal separation. Maybe there is an expert opinion?