While exchemist's #147 gives the proper clues, once again danshawen you exemplify the truth of the eternal equation SF = perpetual Groundhog Day.
A refresher for what is an off-topic subject but who cares that is standard for this forum anyway:
http://www.sciforums.com/threads/all-photons-move-at-300-000km-s-but-dont.149931/
Start at post #6.
That's because we got sidetracked into a discussion of inertia, which I don't believe has been properly digested by the current physics, particularly the particle physics community. Gravitational mass = inertial mass. That's a fact, and to a high degree of accuracy, but what does having inertia REALLY mean, apart from Galileo's ideas and Newton's first? If the Higgs mechanism is going to impart inertial mass, it isn't going to be able to do that without simultaneously imparting gravitational mass, because of the equivalence principle and various and sundry other names for what is basically the SAME principle of pedestrian physics.
Does a beam of photons bouncing between two mirrors aboard a spaceship have "inertia"? YES, evidently, it does, or else you would not be able to bounce a beam between two mirrors RIGHT HERE, on SPACESHIP EARTH, without the beam wandering all over the place instead of staying in one spot, the way it manifestly does, for example in the current LIGO replay of Michaelson-Morley. The bouncing beam of light shares the inertia of the mirrors and beam splitters it is reflected from, as explained in my responses to exchemist.
Or else, the derivation of E=mc^2 used by particle physicists EACH AND EVERY DAY at the LHC must be in error, because a emitted and re-absorbed massless photon is at the very foundation of it, no question about that whatsoever. Relativity itself is about time, bound, and unbound energy, the exact measure of which is always relative to an observer's state of motion. This much is simple and reasonable to ANYONE, even someone without the extensive training in physics folks like us have enjoyed.
Relative states of motion are easy enough to measure, unless it is your wish to measure a state of motion of something with respect to inertialess space. That is impossible, since 1905. The speed of light is the same in every reference frame, and THAT would be impossible too unless the instant of "now" were the same everywhere (and it IS). There's your entanglement. Absolute space is dead. Absolute time has only an origin; the instant of "now". Everywhere else, time proceeds at different rates. Any given interval of time is of a different duration everywhere, which is to say, only an instant, in terms of events, has even a possibility of simultaneity, and this is limited to something that is either the same event viewed from different perspectives, or is derived from events that are entangled (and which always involves the instant of "now" in terms of simultaneity). This is also why it makes perfect sense for the Higgs to be the only kind of boson that is entangled EVERYWHERE.
I did manage to work a bit about Gravity Waves in there. You won't be seeing any of those measured locally either. Since 1905, because Gravity Waves would manifest exactly the same as an "aether wind", and "No problem may be solved by the same kind of thinking as that which created it." -- A.E.