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FrostedFlake -> RE: A rational discussion on the merits of various ship designs in Sci Fi (3/23/2014 1:06:07 AM)
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A few thought on what it would take to make it.
Eddington noted during the eclipse of '19 that starlight is bent as it passes close to the Sun.
Photons have no mass. But they do have energy. And this energy is the equivalent of mass, in terms of being susceptible to the influence of gravity. At the same time, reciprocally and much less surprisingly, if exactly as mysteriously, the mass of the Sun showed by bending the light that it exerted energy. Some might say it is one, but really it is two different observations of the same effect. Mass exerts energy and energy shows itself to be equivalent to mass.
There is more to be drawn from this observation. The absence of mass in the photons coupled with the presence of mass-equivalent energy shows that a moving object has mass over and above and separate from it's rest mass. That is to say, adding speed to an object equates to adding mass. But, how do you add speed to a photon?
In '60, the Pound-Rebka experiment looked at this. The idea was fairly simple. An atom in an excited state that transits to its' base state emits a photon. When the same (kind of) atom in the same base state encounters a photon the same frequency and energy, the atom will absorb the photon and become excited. If the photon is even slightly off, it won't fit. This is the observation that led to Quantum Mechanics. Pound and Rebka exploited this fact in their experiment.
Atop their building they placed a loudspeaker and in it placed a sample of Iron 57. In the basement, 73.8 feet below, they placed another sample and under it a scintillation meter. A gamma ray emitted above that struck the basement sample and was absorbed would not trigger the scintillation counter. A gamma ray that was not absorbed, would. In theory, the iron 57 in the basement should absorb every gamma ray emitted by the sample upstairs. Unless gravity changes something. And it did. Falling toward Earth added energy to the photon, but not speed. The energy added frequency instead. It's totally legal. Frequency is vibration. Vibration is motion. Motion is speed. Gravity blue-shifted the photons and they went right through the sample, triggering the counter.
Clearly, those photons headed up instead of down were red shifted instead of blue shifted. Taken to extreme, the redshift goes all the way to flat. A photon of zero frequency doesn't actually exist. Anymore. This reveals the photon to be something other than an object. That is my original contribution, and differs from particle/wave duality. I think it contradicts, but we'll see.
Getting back to the experiment, they turned on the sig-gen and started applying vibration to the loudspeaker. This moved the sample. They were able to tune the apparatus to cancel the effect of gravity, when the sample was on the upstroke. They read the gear, did the math, wrote the paper got a pat on the back and everything was great. But this experiment does not bode well for high speed space travel. Because it says that flying through space real fast Doppler shifts the radiation encountered on the way. Go fast enough, and the photon flying at you from in front will Doppler shift all the way up to hard X-rays. And that'll keep you coffee hot.
This is why I doubt Earth has ever been or ever will be visited by extraterrestrials. Forget about the energy requirements, I can't see how they could get here alive. A starship built to appropriate safety standards would probably be indestructible, short of striking a star. And, naturally, leaning on it with pride of ownership beaming off his face, would be God himself. Or maybe Gods' kid. depending on how rich God is.
So, turning back to 'practical starship design', I'd have to say it should probably be pretty outlandish. And maybe not actually travel through space, physically, at all. Conveniently, that would likely moot artificial gravity, so is not as expensive as might seem.
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