Perhaps this is one of those subjects where everyone should have an opinion on.  

This is mine: 

NO

We shouldn’t fear aliens invading our wonderful little planet.  

And here’s why, in my most humble opinion, I think we shouldn’t sweat it…

  1. Aliens are coming over and they will take all our water!

A lot of people would say we are the only planet -we know of- that has abundant liquid water…and that is what they want to take from us!  So let’s think about this for a second…it’s been years now since we found out that, even though we are the most visible (to us) water rich planet in our “region”…there is tons of water out there in space!  Scientists have found water clouds containing trillions of times more water than all the seas on Earth combined. 

Moreover, why would you ever want to transport liquid water?  If you are going to move massive amounts of water from one place in the universe to the other, you would much rather do it in its solid form.  Way before reaching Earth, any alien beings would surely identify the millions of water rich floating objects orbiting in the Kuiper Belt.  Already packed, and ready for transport.  So no, aliens are not likely to come looking for our liquid water.

  1. OK, if it’s not water, then, they are coming to take something else!

Like what?  There’s nothing that we have in such vast quantities that would spark the interest of anyone to make such an effort to extract it.

Approximately 95% of Earth is made of silicates, these are minerals made from silicon and oxygen.  Hardly exotic.  Sorry to disappoint, but we are not as attractive as some think we are.  

  1. Aliens are coming to take us and make us their slaves

Let’s see if this checks out…  We have no proof there is intelligent life in the Solar System or anywhere near us (as in light years away).  So let’s go with that for a second.  This would mean that aliens would have to travel many light years to reach us.  It is very unlikely they would send organic beings for such a journey.  Even if they do, they will most probably be aided by very advanced technology.  Advanced enough to travel these unfathomable distances.  We are generations away from that.  But today, we can already find robots to replace us in pretty much every job we’ve wanted to be taken over by a robot.  If at this stage, where we are so far away from interstellar travel we already have robots to do our manual work…what do you think these aliens have?  Do you think they will need our relatively weak bodies which are extremely high maintenance, and extremely fragile?   It’s flattering, but no.   

  1. Aliens are going to use us as power sources, like in the Matrix

Again, these aliens would have mastered interstellar travel.  According to the movie, human bodies generate more electricity than a 120 volt battery.  Aliens crossing the universe to use us as batteries would be like you going to Antarctica to nab a coal stove.