| It's not all that difficult (from a theoretical perspective) to get very close to the speed of light. On the other hand, it's another matter entirely to circumvent it.
I imagine that any other intelligent species that can circumvent the "light barrier" (if it can be done at all) will be so far ahead of us in every other way as to render communication nearly meaningless. Their motivations (among other things) would be practically incomprehensible to us.
Relativistic civilizations are the ones to worry about. Especially if they are nearby. It could be that they aren't here yet, but they're on their way soon. And they wouldn't be bringing a peace offering.
- Rob |