Alien invasion?? could it REALLY happen?

if it happened,I think it would quickly change to guerrilla warfare as armies would probably be defeated in a few weeks

Someone said why would aliens want us, they are so far advanced. This would cover two theories, intelligent slaves, or human destruction before we got to far. So who's to say they are far more advanced then us... we are on the verge of some great discoveries in astro as well as quantum physics (travel/wormholes/dimensional space).. human biology (genetic, neuro, cybernetic) and computers (AI, DNA, quantum, artificial life, nano) ... Any day now any of these could become a breakthrough like we've never seen before with possibilities endless and practical application boundless. Even if it isn't "any day now" we are headed in a direction that will make life as we know it today very different and boring compared to how it may turn out in just a few more generations.