Space aliens and UFOs to me are fallen angels as mentioned in the Holy Scriptures. "Woe to the earth, because your adversary the devil has come down to you." Read a little Bible Scripture and find wisdom. Revelation 12:9 kjv
"And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him." Verses 10-12 "And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of His Christ: for the accuser of our brethren is cast down, which accused them before our God day and night. And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death. Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knows that he has but a short time." One thing the devil does is that he teaches many ways to make war. His purpose is to kill, steal and destroy. How does the devil know his time is short? Because he knows God's word and the Devil (Satan) believes in God, not like some unlearned men of today.