Yes that tachyon visualization is pretty good. Here a video of a hypersonic jet flyby: https://www.youtube.com/watch?v=PQydRIxoAU0 https://www.youtube.com/watch

Yes that tachyon visualization is pretty good. Here a video of a hypersonic jet flyby: https://www.youtube.com/watch?v=PQydRIxoAU0 https://www.youtube.com/watch?v=PQydRIxoAU0 You cannot hear any sound as it approaches. When it is at the cameras location, you hear a boom as a lot of soundwaves hit you at nearly the same time. After that you hear a mix of the soundwaves that the jet produces while traveling away and the other part is the soundwaves arriving from earlier during the approach. Unfortunately we can't really distinguish between those with our ears though a machine could. With light you would see indeed the object suddenly appearing out of nowhere and then splitting into two. One traveling into the direction of time and one seemingly going backwards. What makes things a bit weird are for example time dilation and length contraction. Our equations for those would result in imaginary numbers (e.g. with "i") and at least to me it's a bit unclear as to what that would mean. It is also unclear to me if a particle traveling faster than light would still see light traveling at the speed of light from its frame of reference. FTL comes with causality issues/paradoxes, the easiest to comprehend video on that topic that I've seen is https://www.youtube.com/watch?v=an0M-wcHw5A https://www.youtube.com/watch?v=an0M-wcHw5A From the perspective of a being that can sense only sound the hypersonic traveling jet would be equally confusing - it could assume that there must be things happening in another dimension, one that it cannot sense/observe. And so one could theorize that an object being able to travel faster than light could exist in a dimension outside our 4 spacetime ones - one that we cannot observe directly.