Aliens - random thoughts

One day in dream I had these crazy thoughts. What if aliens are living among us and we can't see them thorough our eyes just like GOD(There is another post where we will debate on this). Take for example bacteria or virus or any microscopic organisms we can't see with our naked eye nor can we feel their presence in our environment. So spacecrafts or missions to check presence of water and life on mars or other planets, are they doing something else apart from taking photographs with various kind of cameras? Are they checking for Microscopic organisms in other planet ? Do they conclude NO life just by seeing the images taken from satellites. Do microscopic organisms have life? May be our definition of LIFE needs to be modified. According to me everything in nature has life. Including the mountains, plants, rivers, rain, etc.

So what if aliens (so called creatures that assumed to coming outside from Earth). We know that we(humans) can live on land. What if they(aliens) can live only on or above water/Ocean. Say they if they have to come to land they have to use flying saucers(Assumption).  It could be very well possible. ;-)
          All our understanding of the earth universe, how life originated, etc are not true. I mean to say we have only theories NO proof till now(LHCollider?). We are inside the box(Earth). We can not think anything outside of it. As of now we can't even say  how life has originated on Earth.
         One simple example. Let's take a tree. The cow sees the tree in different shape, size, of different dimension However human perceive the tree in a different manner.  So why Does the earth that is looking(actually for us) like a spherical to should be in spherical shape for others too.  
So why the hell I am crapping all the one above..Ya there may be aliens on other planet also microscopic / Nanoscopic / Picoscopic ;-) but we are only checking for existence of humanlike or human known (animal/plants) in the planetary missions.   There are few things only GOD knows it. Even if we humans try to know or understand we won't get it. That's it!