> We do not have any other way to accelerate a body to very high speeds, except by using forces that ultimately are based on electromagnetic interactions (this

> We do not have any other way to accelerate a body to very high speeds, except by using forces that ultimately are based on electromagnetic interactions (this includes the pressure of a hot gas that creates a high speed rocket jet). On the other hand, we can detect neutrinos which are the product of beta decay, which is due to the weak force and not electromagnetic interactions. (We can also make neutrinos as part of an artificial nuclear reaction, like a nuclear power plant.) They are slightly slower than the speed of light. This shows we don't need to have the ability to accelerate a body to very high speeds to be able to detect non-electromagnetic bodies at high speed, even if that detection is only indirect, eg, by noticing how energy apparently isn't conserved. > There is a possibility to describe the apparent mass increase of a fast-moving body, which limits the acceleration, as a consequence of the reduced effectiveness of the electromagnetic interactions when the relative speed of the interacting bodies approaches the speed of light. If that were so, wouldn't the neutrinos produced in a particle accelerator (starting from particles going at near light speed) have different observable properties than neutrinos produced from a non-relativistic source like a nuclear reactor or the Sun? Since neutrinos aren't affected by electromagnetic interactions, they should not be affected by this reduction of effectiveness, right? And this should be easily measurable, right? In fact, we should be seeing them already in neutrino detection experiments, yes?