This is assuming they are as smart or smarter then us and are mainly peaceful.

1. Church

   Lets say we go and find ET or ET comes and find us how will the Church react. It would completely murder any hope of the creation story being a history lesson(Most Christians think it’s a metaphor… fair enough). Would the Churches of the world change their teachings saying their God, gods, or deities created the ET’s also or would they say the ET’s are beings from the Devil(or whatever the negative evil being is in their religion)

2. Physics

   The doors that would be opened up in Physics would be astounding. ET would probably come from a planet many many light years away that would mean that the ET’s who find us mastered some crazy currently theoretical physics such as faster then light travel(which could potentially mess with Time itself), or maybe wormholes. Also they don’t know anything about Einstein they could have entire other laws of physics that conflict with our Quantum Theory and our Theory of Relativity. Maybe they have just 1 theory for everything … A theory of everything kind of like what Dr. Michio Kaku is trying to do with String Theory.

3. Read more in Life

   « What Do Teenagers Want?

   10 Reasons for Failing Phys Ed »

   Chemistry

   Would Alien Chemistry be the same as ours? Will they even have the same elements making them up? Maybe the aliens wouldn’t even be solids maybe they would be gaseous beings. Will their Periodic Table be massively different then ours? Maybe they don’t even classify elements by Protons and Neutrons maybe they do it by subatomic particles, Maybe they even have found particles smaller then subatomic particles.

4. Lifestyles

   How would our lifestyles change? Think of it now we would have a massive amount of new learning and popular opinion changing. Would some humans be afraid of the Aliens and attack them starting a crazy war? Would Aliens be allowed to assimilate into our society and live in our world? Would we be allowed to live in theirs? We might even get cool new luxuries from them maybe they created a room temperature super conductive material and now we have the ability to do almost anything energy wise. What would happen to education? We would need to rewrite almost every text book even written also think of how hard it will be to communicate with them they might not even use words to speak they might speak telepathically. Also what if they try to take us over … A lot of lifestyle problems could happen but it could also be very beneficial.

5. Technology

   How would our technology change? Maybe they use “Quantum Computers” computers that use atoms to compute instead of 1’s and 0’s. Will we have any ways of connecting their home world to our Internet? What if they have an Internet will they be able to connect to ours? Think of how awesome that could be an alien Internet with an alien youtube. Do they rely on satellites to communicate or do they do something else, something we would consider crazy.

6. Government

   What would happen with our government? Would the entire Earth from that point on be ruled by a single ruler or would we still have our nations? What kind of system of government would the aliens use? I have a feeling if they find us their entire planet would be united and they probably don’t fight with each other and have wars because war is extremely counter productive. If we keep our government system now that would be weak to any planetary alien government. They could easily divide our planet maybe they would strike a deal with the United States that if we help them wage war on the rest of our planet that we would be The master race and leaders of the world. In return we would share all of our knowledge with them.