Takemehome wrote:Here is an interesting question:
You leave earth at light speed, if you can still see the earth,
the image of the earth is traveling faster than light speed to reach you.
According to Einstein, nothing can go faster than light.
Therefore, if you travel at the speed of light, everything behind you vanishes ?
It is postulated that the Doppler effect at near-luminal velocities will create a "starbow", with nothing visible in the center of the path either forward or rearward, and any EM-energy emitting objects left visible in a ring around the middle that shades from near-UV down to lowest reds, for visible light, and above and below that for the non-visible stuff.
The width of the ring narrows as the velocity gets closer to lightspeed, as it is less likely that photons will be crossing your path in an intersection course in a way that you could still intercept and "see".
At the point just below lightspeed, photons coming from the front at any angle will be at such a high energy level (relative to you) that they will be beyond the highest energy detection we can do (by current technology), and that coming from the rear will be at such a low energy level (relative to you) that they will be below the threshold for capture by our systems, being at or below the noise level of the systems.
You cannot test the theory of what would happen *at* lightspeed, because it would theoretically take infinite energy to reach that speed. Probably, you could not even come truly close; perhaps 99.99% or something like that, maybe less, because the universe would end before you could get any faster, with accelerations possible to us now (even assuming a renewable fuel source using something like a Bussard collector feeding a fusion engine--there are large inter-galactic voids out there containing so few atoms that you would be coasting thru them with virtually no acceleration for very long periods).