Psalm 19: 1 – 3: To the chief Musician, A Psalm of David. The heavens declare the glory of God; and the firmament sheweth his handywork. Day unto day uttereth speech, and night unto night sheweth knowledge. There is no speech nor language, where their voice is not heard.
A man can go to an observatory and look at the vast expanse of Space through a powerful telescope, and in his curiosity, he may wonder to himself if intelligent life exists on planets similar to ours in other galaxies within a universe so large and incomprehensible as ours is. The question is settled by looking at the purpose of God in His creating the universe in which we live.
Before the creation, Elohim dwelt alone with His thoughts, His attributes and characteristics unexpressed. In Him was Jehovah, Adonai, El Shaddai, Emmanuel etcetera. When the Logos came out of Elohim, that Pillar of Fire which was Christ created the universe (John 1: 3; Colossians 1: 16 – 17; Hebrews 11: 3), and from the vastness of the universe, God chose planet Earth as the place to express His attributes upon.
If God placed intelligent life on a planet in another galaxy, then why not a third planet and a fourth etcetera? If God did that, then He would have to reveal the plan of redemption in those places where He could be known as the Savior, the Redeemer, the Healer etcetera. But God chose one planet to place His name (Isaiah 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.).
In Revelation 5: 3, no man in heaven, nor in earth, neither under the earth was able to open the Book nor look upon the Book. A search was made of the entire universe, and God was looking for a man, a being with a soul. The angels could not redeem because they have no blood, and a man could not redeem because he was fallen, so if human life could exist in another galaxy, it would still be in a fallen state because the plan of redemption would need to apply there as well.
In Revelation 5: 9 – 10, when the new song is sung, man was redeemed out of every kindred, tongue, people and nation on the earth and was going to reign on the earth, not someplace else. In Daniel 12 and Revelation 10, Michael is coming down to the earth to deliver the names written in the Book, because the names in the Book are on one planet in the universe. It is therefore plain to see that the whole purpose of God behind the creation of the universe was to show forth His great plan of redemption, and the place He chose to express His redemptive attributes upon was this planet Earth.