Gravitational redshift was the decrease in the frequency and energy and the increase in the wavelength of electromagnetic waves or photons travelling out of a gravitational well.
It was also an optical illusion that occurred as an object fell into a black hole. As the speed of the falling object exceeded the frequency of the light it emitted, to an outside observer it would appear to have stopped just outside the black hole. (SNW: "Memento Mori")
In the real world, the term "gravitational redshift" does not have this second definition. Gravitational redshift is not an optical illusion and does not fit the phrase "it (the object falling into a black hole) would appear to have stopped just outside the black hole" in this second definition. The phenomenon that does fit this phrase is called
gravitational time dilation, but it too is not an illusion.
Speed and frequency are
dimensionally different. So, these two physical quantities cannot be compared directly.
If the object falls into the black hole and subsequently travels away faster than light, then the optical illusion is neither gravitational redshift nor gravitational time dilation, but the object appearing to be stopped just outside the black hole to an observer far from the black hole, when the object has actually already escaped the black hole by traveling faster than light. However, on the one hand, due to gravitational redshift, any
electromagnetic radiation going from the object to the observer will have frequency and energy approaching zero and wavelength approaching infinity such that the observer probably will not be able to see the object, and the illusion will be unseen. On the other hand,
faster-than-light radiation can also escape the black hole, and any such radiation going from the object to the observer will give away the trick.
In 2259, Captain Christopher Pike took advantage of gravitational redshift to deceive a Gorn destroyer into believing that the USS Enterprise had been destroyed, by accelerating toward the central black hole of the Finibus system while detonating an AP 350 atmospheric processor behind it. Lieutenant Erica Ortegas termed this the "Pike Maneuver". (SNW: "Memento Mori")
In the real world, the Pike Maneuver can be described in the following manner: Pike took advantage of a combination of the block hole, gravitational time dilation, light (electromagnetic radiation), and
warp drive to deceive the Gorn destroyer. He would not have wanted to take advantage of gravitational redshift for the reason that at the black hole, this gravitational phenomenon would have redshifted the electromagnetic radiation to undetectability, rendering the illusion unobservable. He would have had to offset it. To do this, he would have had to exploit electromagnetic radiation with frequency and energy approaching infinity and wavelength approaching zero. And because
subspace radiation could travel faster than light, escape the black hole, and reach and alert the Gorn, he would have had to order
subspace silence.
Furthermore, in exploiting this optical illusion, Pike would only have allowed the ship to linger close to the black hole just long enough for the ship to emit light to any observer far from the black hole. Because of gravitational time dilation, the longer the ship lingered, the further into the future - up to the end of the
Universe - the ship would have traveled when it warped back to a distance far from the black hole.
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