English: Tachyon visualization. Since a tachyon moves faster than the speed of light, we can not see it approaching. After a tachyon has passed nearby, we'd see two images of it, appearing and departing in opposite directions. The black line is the shock wave of Cherenkov radiation, shown only at one moment of time. This double image effect is most prominent for an observer located directly in the path of an FTL object (in this example a sphere, shown in grey). The right hand bluish shape is the image formed by the blue-doppler shifted light arriving at the observer -- who is located at the apex of the black Cherenkov lines -- from the FTL sphere as it approaches. The left-hand reddish image is formed from redshifted light that leaves the sphere after it passes the observer. Since the object arrives before the light the observer sees nothing until the sphere starts to pass the observer, after which the image-as-seen-by-the-observer splits into two -- one of the arriving sphere (to the right) and one of the departing sphere (to the left).