>>80446007Imagine a railgun but bigger. Accelerate a decently large metal projectile with magnets to fast enough speeds and you can cause an extinction level event greater than the ones our planet has ever seen before. Or simple accelerate it over the extremely long distance it has to travel with more conventional methods, you don't need to slow down when you get to your destination after all. Building something like that is feasible on earth with some effort and our current level of technology. Any bystander to the attack would have to wait for that light to reach them to notice on top of noticing the extremely minute change on that little dot in a miniscule part of the night sky. Maybe after hundreds or thousands of attacks you could put together a pattern but it'd be extremely difficult to respond in any meaningful way except shooting back.
>>80446161So do the aliens just have 360 degree hyper high definition vision of the entire night sky at all times to observe all changes in light on all potential life bearing planets? Even assuming that's a relatively simple thing to do the only meaningful response you'd have to that given relativistic distance and response time is shoot them back. At which point the best option for anybody is to remain quiet in the first place.
