Dude, we are talking about a culture that can to FTL jumps. They are NOT using chemical reactions to power ships of any sort. So, no huge plume of brightly burning gas to be seen by a telescope. There's probably a nice quiet ion drive back there - little reaction mass used. Cheap. Low thrust, low emissions. Gravity does most of the work for you.
This is a straw man argument. At no point did I state the use of chemical rockets. It doesn't matter how you generate the thrust, the energy used is still the same (give or take any waste energy coming off as heat) and the delta-V is still the same.
You're changing goalposts and assumptions. You're making an implict assumption that your technology of choice is stealthy on a scale of shifting a multi-billion ton asteroid. At no point have you stated this assumption or said anything to back up this argument.
Um, dude. The thing that actually killed the dinosaurs had no reaction mass at all. It just fell from the outer solar system to the inner system. Yes, it takes time. You lack patience, grasshopper?
This is a red herring fallacy - introducing irrelevancies. Of course the actual Chixulub impactor had no reaction mass - it wasn't being aimed artifically, but just happened to be on the right orbit to hit earth, so it didn't need it. The discussion is specifically about somebody artifically shifting the orbit of a dinosaur killer.
Okay, so the Earth itself is moving at about 30 km/sec. You can pop a rock out of hyperspace dead still right in its path, and have that much relative velocity. WHAMMO!
You're shifting goalposts again. Now implying that it's trivial to move a dinosaur-killer through hyperspace, a new set of arguments that wasn't brought up before. Nothing offered to substantiate it.
So, what you are saying is... you, here and now in 2020, have the computer power on your own laptop sufficient enough to do that job. So, thank you for proving that the computing power for guidance isn't a barrier....
This is another straw man argument. I never stated that computer power was an issue.
This will not be prevented by anything as simple as "where do you get the velocity" or "math is hard!" as if our aggressors are frelling Barbie. Which is why I ask why it doesn't happen.
This is a hasty generalisation, Just saying it's possible in principle and that some trivial things don't say it can't, therefore it will happen. You haven't engaged further to explain your arguement.
This is also a straw man argument. I never said it was impossible, just hard to do without being noticed and much easier to undo than to do in the first place.
I'm calling you out on this. There's almost nothing in your post that wasn't disingenuous in some way. Please don't do this sort of thing. There's no point in engaging stuff like this if you're not going to argue in good faith. You've avoided the original suggestion, which is that the large energy expenditure needed for the delta-V to shift a dinosaur killer makes it difficult to do without being noticed. Instead you've decided to poo-poo a strawman interpretation of the post with a series of rhetorical devices and introduce your own new set of assumptions without bothering to state them. You're clearly not discussing this in good faith but pulling out rhetorical tricks to win an argument. If you don't want to be dismissed as a troll I suggest you don't engage in this behaviour.
You've previously posed a question about why it wasn't going to happen and I stated a scenario, specifically that the very large energy expenditure makes it hard to do without being noticed. I may not have been clear about defence, but I'll clarify it now. If you catch it early enough, you only need a small amount of delta-v (most efficiently applied prograde or retrograde), to deflect its trajectory so it misses. That's orbital mechanics. Ergo, it's much easier to defend against such an attack than to make it, by several orders of magnitude. That's a conceit that you can put into your game without needing handwavium over and above the assumption that such an attack could be made in the first place. The same technology used to make the attack can be used to defend against it, but only needing to be deployed on a much smaller scale.
That's before one asks the question of whether the scale of this endeavour makes it cost effective anyway - given the fantastically large amount of energy involved, is it cheaper to do it some other way - perhaps just rock up with a fleet of warships and attack the planet in person?