Extraterrestrial
Dictionary Definition
1: originating, existing, or occurring outside the earth or its
atmosphere
2: a being from another world extraterrestrial being
Extra when used as a prefix means outside or beyond and terrestrial is relating to the earth so it just means something outside of or beyond the earth.
Similar to the word "supernatural," the word refers to anything outside of the earth. Angels and demons are definitely extraterrestrial and they are real. Whether they exist in another dimension or we just can't see them, they did not originate on earth.
In most people's thinking, when they hear or talk about extraterrestrials they think about aliens from another planet and typically are related to UFOs or flying saucers.
Do aliens from another planet exist? We have no proof but it is highly unlikely. We have enough knowledge of the planets in our own solar system to know there are no intelligent beings there. That is out. So they would have to be from a planet around another star. The nearest star is 4.25 light years away or 9.461 x 1012 km (5.88 x 1012 miles). The fasted vehicle we ever sent into space was the Parer Solar Probe that achieved a speed of 153,454 MPH. That probe would take 38,317,671 years to reach the nearest star. Obviously it would take something well beyond our capability or known scientific method to reach that star in a reasonable time. That is why science fiction had to invent "warp drive" or "FTL drive" because there is nothing we know of that can travel fast enough. Worm holes or space warping has been proposed as a possibility but the reality is that those are extremely unlikely possibilities.
There is a much more likely explanation for extraterrestrials and that is what we already know about extraterrestrials. They could be demons. This of course requires a lot more explanation which I don't have time to go into right now but Satan has an agenda and UFOs and extraterrestrials fit very nicely into it When the rapture occurs and millions of people suddenly disappear, there will need to be an explanation for it. Aliens! We have been being inundated with evidence, conjectures, science fiction, and observations so that explanation will be perfectly plausible to the vast majority of people left on earth.
Much more to come.