2. THE BIBLE
(a) Scripture does not mention ET visits.
The Bible, the revealed written Word of God, teaches that life is only possible through a process of creation. Even if there were other galaxies with planets very similar to Earth, life could only be there if the Creator had fashioned it. If God had done that, and if these beings were going to visit us one day, then He would surely not have left us unenlightened about this.
God has given us rather specific details of the future for example, the return of Jesus, and some details about the end of the world. The universe will, at some future point, be rolled up like a scroll (Isaiah 34:4, Revelation 6:14). If God had created living beings elsewhere, this would automatically destroy their dwelling place as well. Adams sin caused all of creation to be affected by the curse, so why would a race of beings, not of Adams (sinful) seed, have their part of creation affected by the Curse, and then be part of the restoration brought about by Christ, the last Adam? All of this would seem exceedingly strange.