Who has seen the aliens except the aliens themselves? Where are they seen except in movies? However some people time to time claim to have encountered with them which is nothing more than a business stunt.
Some scientists, after all, have somehow made the possible sketch of the aliens which is controversial and full of illusion. Suppose we agree some people have seen the aliens.  Let's agree for a while they have been seen by scientists. But how can they determine the actual face of an alien without having their physical presence?

Let me clarify this. Suppose our spacecraft with astronomers unknowingly reached near the planet of aliens and they saw the astronomers. But they did not find them. Then what type of sketch will they make for our shape and face? Definitely they will think all humans like an astronomers. But they don't know the real body shape and face of a human which is covered in the space suits.

If the aliens had been seen on the earth, they are also astronomers and are seen in space suits. Can we estimate the real face and shape of them without getting their physical presence? Obviously not.
Discovered by +Don Prince