There would be many people who will have the usual "end of the world" scenario in mind. Many religious beliefs would crumble, but as history shows us, there is a good chance new age beliefs would be formed based on these events. Many humans have a tendency or need to idolize or worship things out of the normal.
Mind you this is speculation, but I also feel the governments who have knowledge of this phenomenon are simply too embarrassed to let this information out. Mostly because I feel they don't know the whole story about them either.
Btw, sorry for getting off topic.
when you as people (human kind) do not understand something we try to figure it out,,it can take 10 years 30 years 50 years and even 100 years and 1000s years,,
when we as human beings do not understand it we learn it ,,in this case some parts in the big birocracy of goverments ,,that is also what happen in usa since 40s when first craft been captured
one thing about the human race that you need to know about (happens in particular section of goverment related to military affairs) is that they like to learn things before declaire them and release them to public knowledge base,,and if the there is something that still not understood it wont be released to public knowledge because the govrmer also acting as protector of its people and its structure
when it comes to the us (specific sections of the military/goverment) operated in s4 as part of area 51 with out the need to report to president and with out constitutional law or rules,,and still to this date do though added many other locations ,,those sections of the military/goverment still to this date havent figure out how to fly the crafts and how to operate it ,,especially cant and wont figure out related date because some compounds are missing since they are extra terrestrial compounds as in not from this planet,,
element 15 is only now being stabelized and there is not supply of it on earth since it comes from what we captured and its limited,,element 15 after 50 years of advanced research STILL havent being figured and what that tell you is that the human kind is simply not ready for interaction with super advanced societies,,we are part of time,,we are part of space and we are pasrt of a bigger thing that i believe truely controled by one god ,,but we are only small tiny part of it called the human kind and we are very young in out development in relation to the ones who came here and looked over us,,
so in general ,,you may feel you are ready but in reality its a lot more than god related beliefs ,,it is more to do with the fact we cant figure out anything about them or to be exact we figured out very little in 50+ years and we have the best human researchers doing the work and risking their lives and still nothing,,why?
because we are not ready ,,yet! i believe next 100 years when we have base on mars and ofcourse sucesfully getting on the moon so we can get to mars with our vehicles,,,i believe that after this we will be more ready since new elements sources of materials wil be available for human kind
for now all you can do is know that they been here and you are not crazy,,the stuff we can get out of 50+ years of research we try to put into military machinary and it has been quite small in relation to what could have been done if we had the capability to understand all and gain a hold of the materials needed
anything i wrote above is above and beyond president of usa,,it is controlled by specific sections of the us military and goverment and has no obeidence to the constitution of the usa ,,it also happen in other countries around the world and treated and followed to the t with the code of rules that the us and ussr presented along last 50 years as the only super powers on this planet