Do UFOs/ETs exist, are they real?

I am confident that life exists elsewhere in the universe, and especially in our galaxy. Some of this life has created civilizations. I am surprised that the Search for Extraterrestrial Intelligence has not detected radio waves from extraterrestrial civilizations.

Nevertheless, in his Theory of Relativity Albert Einstein asserted that nothing could travel faster than the speed of light. Correct me if I am mistaken, but I believe that whenever an assertion of Albert Einstein has been tested it has been verified.

This barrier on space travel means that if intelligent beings have traveled to earth they have made major sacrifices. By the time they get back to their home planet their species may have become extinct, or it may have evolved into something else. If they come here I doubt they will look around and return to their home planet. I think they will identify themselves.

 

Who knows but if they are here they would have colonized us by now.

 

The distances are just too great. There could well be intelligent life elsewhere in the universe but we will never encounter it. Travel between us and alpha centauri - our nearest neighbor star (actually a cluster of 3 stars) would require over 30,000 years with current technology and there is no evidence of any planets there that might support life as we know it.

There is no proof at all that we have been visited by interstellar aliens, all hope and wishes aside.