AI 中文总结
本文通过时空图证明，超光速加速物体的滞后时间可存在多个取值，不止两个，还能出现三个影像，以USS Stargazer号的超光速机动为例说明这一效应。
AI 中文摘要
由让-吕克·皮卡德舰长指挥的USS Stargazer号与一艘费瑞吉飞船交战。为在战斗中求生，Stargazer号采取了超乎想象的行动：以超光速向费瑞吉飞船移动，在即将相撞前停下。据称费瑞吉飞船会看到Stargazer号的两个影像，最终击中了错误的那个。本注记中，作者用时空图证明，实际上费瑞吉飞船最多能看到Stargazer号的三个影像。这提供了一个简单示例，说明当物体超光速运动时， retarded time（ retarded time 可译为滞后时间）可存在多个取值，且当物体能加速时，这些多个取值并不局限于仅两个。
英文摘要
The USS Stargazer, commanded by Captain Jean-Luc Picard, battles a Ferengi vessel. In an effort to survive the battle, the Stargazer does the unthinkable: they move toward the Ferengi vessel at a faster-than-light speed, stopping just before a crash. The Ferengi vessel is said to see two images of the Stargazer, and ends up shooting the wrong one. In this note, I show with spacetime diagrams that, in fact, the Ferengi vessel sees up to three images of the Stargazer. This gives a simple example of how there can be multiple values of retarded time when an object moves faster than light, and how these multiple values are not restricted to only two when the object can accelerate.
Comments4 pages, 4 figures. To appear in Am. J. Phys
