Yes, everything's a lot sexier at >0.1c :-D

While in upper secondary school, I studied basic physics, including some theory of relativity and quantum physics. One of the last things we did was a short, individual project. Young and reckless as I was (am) I decided to put some thought into this.

I first considered talking about the prospect of using radioactive material as propulsion for a space ship, directing the radioactive emission backwards, thus creating a minuscule thrust.

I then attempted to draw a graph of the ships acceleration as a function of time, taking into account the time dilation at relativistic velocity as well as the amount of remaining radioactive material.

Then it came to me. Since the mass of an object increases as it approaches the speed of light, the mass of the unstable atoms should also increase. I assumed this change in mass would also affect the mass/energy of a gamma particle being radiated. Since the mass of a gamma particle is dependent on only its frequency and c (can't remember what the equation is called), I figured the wavelength of a particle emitted at relativistic velocity should differ from that of one emitted at nonrelativistic velocity.

If the particle emitted was unaffected by the velocity, then the decay product would have a greater mass than had it decayed before it accellerated to relativistic speeds, I thought. My physics teacher couldn't answer if I was right or not, I got my MVG (highest possible grade) for the assignment, but I'd still like to know if this is a well-known effect or if there's some flaw in my logic.

Well, hope anyone bothered reading it through; perhaps I even entertained someone with my ignorance :-D