If you travelled at exactly the speed of light, what would the stars look like behind you? was closed as off topic, reasons include
I think that it's clearly not relevant to space exploration (if Alcubierre 'drives' are possible at all, they're not possible for us).
We have a couple of hundred posts on the Physics stack on the Alcubierre drive that you might like to browse. As you can see, such questions have a fairly high probability of getting closed.
Of the 10 questions tagged alcubierre-drive this was the only closed for being off-topic. The previous nine can at least be inferred to show that the community has decided that faster-than-light alcubierre-drive questions are not off topic simply for that reason.
Of the 7 questions tagged ftl or "faster than light" three were closed as off-topic, two of which for more fundamental reasons than topicality.
- What objects travel at the speed of light? not a good question
- How does Santa travel to other galaxies? bah! Humbug?
Question: While the first nine Alcubierre drive questions were on-topic, why is what an astronaut would see gazing out the back window be off-topic?
We have dozens of questions about what astronauts see out windows of capsules, lunar landers, shuttles and space stations, why can't we allow further answers to a question about what an astronaut would see out the window of this on-topic spacecraft?