It was pointed out here that the speed of light is a huge issue for any government that spans multiple stellar systems. The consensus seemed to be that it is very difficult to make large empires work.

However, I don't think that anyone said that such empires are impossible. . .

So, I figured I'd ask about galactic empires, a common sci-fi trope. There are some issues that stem from the speed-of-light problem:

• Communication
• Shuttling troops to battle
• Sending diplomats/envoys to different star systems
• Ensuring that civilizations survive long enough for any of the above to be remotely possible
• Biological/sociological/technological diversity among different species.

These are but a few of the many problems that a galactic empire would face. There are, of course, many others.

So, how could a galactic empire stay stable for any significant amount of time (i.e. millions of years)?

It was pointed out here that the speed of light is a huge issue for any government that spans multiple stellar systems. The consensus seemed to be that it is very difficult to make large empires work.

However, I don't think that anyone said that such empires are impossible. . .

So, I figured I'd ask about galactic empires, a common sci-fi trope. There are some issues that stem from the speed-of-light problem:

• Communication
• Shuttling troops to battle
• Sending diplomats/envoys to different star systems
• Ensuring that civilizations survive long enough for any of the above to be remotely possible
• Biological/sociological/technological diversity among different species.

These are but a few of the many problems that a galactic empire would face. There are, of course, many others.

So, how could a galactic empire stay stable for any significant amount of time (i.e. millions of years)?