Terrifying you mean!!! In that circumstance, I would thing the "turtle" defense would be in order, no radio signals or anything leaving the planet, so the victors would just keep on keeping on after the fight. Any two civilizations that could come all the way here to fight each other could easily kill us all, just one of them could. What a thought!!! I was watching on a show that we spotted a large explosion several hundred light years away that has no cause, there was no star there or anything else, just a big boom that lasted a few days and was gone. Makes me think we may have seen the end of a large alien star ship, or star base, that went boom in a big way.