i guess people are not relating to my 'why not radar?' question, because somehow by just bringing this up, is demonstrated a lack of even basic understanding of how astronomical equipment is used for that goal. But yet can anyone please try and explain in simple words, how far away is current technology from being able to detect by radar at least 2 months ahead, an asteroid coming at an angle that optical and infra-red means are unable to detect ? Or are optical and infra-red means still a better possibility and if so, what improvements are needed to be able to do that in a case such as with 'Oumuamua? i mean, people are talking here about nukes and other very late time to impact options, but why does no one discusses ways to make it an earlier detection case? Is much earlier detection such an impossibility?