I have a crazy idea that will not go away. So I after much resistance I have decided to post it here to see if my house of cards can stand up to sensible scrutiny. I have watched a lot of the Hollywood alien invasion movies. All of which seem to assume that the Aliens have terrible tactics. They all end up getting killed in hand to hand fighting. Why? To my mind, if an Alien race wanted to attack us, then they would have to commit huge resources to the venture. Assuming no faster than light travel, then the Aliens will have to get here the hard way. Taking hundreds of years. So the gains have to be worth it. They also have an enormous supply train problem. They have to bring everything they will need with them, or know that it is available here. So here comes assumption number 1. Any alien invasion will first have scouted us out. There is simply no point sending in a significant invasion force blind. Assumption 2. If a scout gets here and sees that we have potential, then it will send a signal home and stay here. Continuing to monitor us. Because it is sensible to have up to date intelligence on your enemy, and because the scout may have additional resources that you may need. Assumption 3. We are more vulnerable to alien attack at our current stage of development that we ever have been before or will be in the near future. This requires a bit more explanation, and some considerable speculation. Any alien race capable of sending an interstellar invasion force must be highly developed technically. Will have expanded throughout their own system, and will have mined and extracted and used all the minerals that they can. If they continue to expand then sooner or latter they will want to look outside their own system for the resources. Say these are the Rare Earth elements. Now would it be easier to go to a neighbouring system and try to look for these elements and then mine them, or to go to a planet that has already mined them and has them readily available. At our current stage of development we are heavily dependent on technology, on mass farming and mass distribution. We are also only just putting a toe into space. So any invasion force, having taken a hundred or so years to get here, will not mind taking its time destroying us. Just sit in high orbit. Throw rocks at anything likely to be a potential risk to it (airport, missile launch facility, etc) throw a few more rocks to destroy all bridges, power stations, dams, power distribution grids, and all sea ships. Then drop a enough rocks to simulate a nuclear winter and sit back and wait for disease, famine and cold to kill off the vast majority of us. After a few years they could demand whatever they want from us. It would make a poor movie, but good tactically. Assumption 4. The invasion force will try and sneak up on us. The element of surprise is a good one. If we see them coming, decelerating into the solar system, then we can have a few months preparing. If however they timed their approach so that we were on the far side of the sun we wound not see them until they were much closer. The scout, presumably still here, would also be much closer. Perhaps on the far side of the moon, or at one of the trojan points. It could be used as an advance guard to take out any initial potential threat we could put up. So there it is. A possible invasion plan. I apologise for being cheeky and for this being my first post, but what do you think?