So, the way your question is worded, those who believe in alien life outside of our planet need no facts, only belief? That's good, because they have no facts.
I do NOT believe in alien life outside our planet, and the facts on why are biblical.
First, God is just:
Deu 32:4 He is the Rock, his work is perfect: for all his ways are judgment: a God of truth and without iniquity, just and right is he.
Isa 45:21 Tell ye, and bring them near; yea, let them take counsel together: who hath declared this from ancient time? Who hath told it from that time? Have not I the LORD? And there is no God else beside me; a just God and a Savior; there is none beside me.
Furthermore, ALL OF CREATION GROANS AND TRAVAILS because of sin:
Rom 8:22 For we know that the whole creation groaneth and travaileth in pain together until now.
Christ DIED ONCE for the sins of mankind:
Heb 9:28 So Christ was once offered to bear the sins of many; and unto them that look for him shall he appear the second time without sin unto salvation.
Heb 10:10 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.
1Pe 3:18 For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit:
Finally, the Bible speaks of earth, sun, stars, heavens, and even names specific stars (see Job 9:9 and 38:31) but the EARTH is the only location mentioned in scripture which was CREATED to be INHABITED:
Isa 45:18 For thus saith the LORD that created the heavens; God himself that formed the earth and made it; he hath established it, he created it not in vain, he formed it to be inhabited: I am the LORD; and there is none else.
Come now, let us reason together in accordance with what we have just read. If there WERE life on other planets, they would be under the condemnation of sin in accordance with Romans 8:22, but without the hope of a Savior, because of the words ONCE and MANY in Hebrews and 1 Peter, which were written to MEN, NOT SPACE ALIENS...
These actions DO NOT FIT the profile of a JUST GOD...Therefore; scripture does NOT support the idea of extraterrestrial life. It is my personal conviction that the search for life on other planets is an expensive and vain attempt to validate evolution.