No
the existence of extraterrestrials is a paradox
No aliens, in the sense of extraterrestrials, are known and proven to actually exist.
This theory has proven the existence of God
Their existence is not proven.
Western medicine has not proven the existence of meridians and acupoints
Their existence is not proven.
Possibly. Their existence has neither been proven or dis proven.
Crows have been proven to be the most intelligent species of bird in existence as of 2011.
Although we have no definite knowledge of any extraterrestrials, and we certainly do not know that any extraterrestrials have received any messages from us, we have sent a number of things into space, notably radio and TV broadcasts and various robotic space probes, which would convey information to extraterrestrials if the hypothetical extraterrestrials received them.
Yeti's existence has not been proven.
Barlowe's Guide to Extraterrestrials was created in 1979.
The ISBN of Barlowe's Guide to Extraterrestrials is 0894805002.