If my (admittedly rough) understanding of relativity is correct, there's a problem with this weapon: From the recipient's perspective, the shell would never arrive.
Basically, as the shell accelerates to C relative to the target, time in the target's reference frame expands relative to time in the shell's reference frame. A shell traveling at C would instantaneously travel from origin to destination (from the shell's perspective) but would take infinite time (from the target's perspective).
Of course, an impact at 1% C would still make one hell of a bang.
> would take infinite time (from the target's perspective).
this doesn't sound right - the shell does arrive, and arrives exactly X light years after being launched, as measured by the alien. Its just that from the perspective of the people in the shell, heaps of time has passed on the outside.
But my knowledge of relativity is cursory at best, so im not sure if i m right.
Basically, as the shell accelerates to C relative to the target, time in the target's reference frame expands relative to time in the shell's reference frame. A shell traveling at C would instantaneously travel from origin to destination (from the shell's perspective) but would take infinite time (from the target's perspective).
Of course, an impact at 1% C would still make one hell of a bang.