We rely on our 5 senses.... What if there are more senses than we could fathom???? What if the alians are already among us and we are just not aware of their existence due to our limited amount of senses???
What if there is/are other parallel dimensions that we are oblivious of???

The same questions can be asked about alians ability to detect and interact with us....

As per Einstein we have E=mc2
Is it possible that existence is also possible in pure energy state apart from matter...

We human are made of matter, so is it possible that there is some existence made completely of energy???

We human are trying to look beyond the door through a key hole... I don't know if the our existing laws are sufficient to explain every thing... We really don't know anathing beyond the relm that we know of!!!

We even are not close to solving the "Millinium Problems{1 is solved by far} ...