Ok basically most people here have been talking about aliens being… advanced, intelligent etc…
But first you must consider this…
In order for life to exist on a planet, we would assume that the planet sustains liquid water, because water is the only element used by all organisms on earth so therefore is a key factor in sustaining life.
For this to occur, we must find a planet that is orbiting a star similar to the distance of earth from our sun with similar heat, luminosity, radiation emission etc.
We must find an earth like planet…
We assume this because out of the 300 or so stars that have been examined, there specs don’t match our suns specs and some of the planets found around them do not have detected liquid water.
Another key element is carbon, which all living things are mad out of YES EVEN YOU! This is because carbon can make very very very stable bonds and lots of them.
Oxygen, Nitrogen and Hydrogen are also the main scaffolding for living things because of there stability and bonding properties. If we were made up of anything else then we could possibly explode due to instability.
So IF we encounter an alien the chance of them being made out of what we’re made out of is pretty high.
IF NONE OF THIS MADE SENSE then at least think about this…
If “aliens” exist, this doesn’t mean they are more advanced than us. YOU KNOW WHY??
Because they may simply be microscopic organisms or plants or some sort of creature that shits, eats and has sex all day that hasn’t had enough time to evolve and walk out of the water like us animals have!! Or they just don’t give a shit.
But seriously an alien doesn’t mean a creature with 2 arms, 2 legs, 3 tits haha, and big green round eyes. It could just be something as simple as bacteria.