The Bible tells us that "In the beginning God created the heavens and the earth" (Genesis 1:1).
This verse means a lot.
This means God created heaven (where God's throne is). He also created other heavens. In fact, the Bible tells us there are three heavens (2 Corinthians 12:2).
The first heaven is the sky (or atmosphere above earth). The second heaven is outer space where the stars and galaxies are. The third heaven is where God's throne is.
The Bible also tells us that besides creating humans, God also created angels.
Angels are ministering spirits (Hebrews 1:13-14).
They are not alien life, because they are spirits who do not depend on water or air to live.
However, they are other beings who have mighty power and they come and go, and can travel anywhere in the heavens and earth.
The fact that earth's environment is very human centric actually show the truth of the Bible. The earth was made for us and changes in weather, atmosphere, or distance from the sun can cause human life to cease completely.
So earth is very special to God and Jesus appeared on earth.
"For by Him all things were created, both in the heavens and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things have been created through Him and for Him. He is before all things, and in Him all things hold together." (Colossians 1:16-17)
Jesus is well-known among the angels too (Hebrews 1:4).
There are good angels and bad angels. Just as there are humans who purposefully decide to do evil and not follow God, there are angels who decided to be rebellious against God too.
The first angel who rebelled was Lucifer (who became Satan) and other angels followed him. There have been "alien encounters with humans". However, these encounters are bad angels disguising themselves as extraterrestrials to deceive humans into believing in false doctrines.
(If you're interested in this topic, please see more information from this video that explains how alien abductions can be halted by the name of Jesus: https://youtu.be/f4Pi90Q6vno)
Unlike humans who can be redeemed by Jesus, angels who rebel can never be forgiven. The reason is angels continually see the face of God (Matthew 18:10), and their decision to rebel is an unforgivable betrayal.
The Bible also hints that each star we see represents a good angel (Revelation 1:20).
So there is a reason why we have so many stars and galaxies.
In a way, they are a physical representation of the spiritual world.
Perhaps in the future when Jesus returns to reign on earth, He will put to use these distant galaxies and planets.
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For now, there are no intelligent life on other planets.
The Bible talks about God creating angels and humans. But the Bible does not mention God creating beings on other planets. Perhaps He will create new beings in the future. But for now, there are no extraterrestrials.
Aliens are actually bad angels who disguise themselves as ET to deceive humans into believing in false doctrines.
Their job is to hide the truth.
ET are actually bad angels or evil spirits in disguise.
"But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed!" (Galatians 1:8)
"No wonder, for even Satan disguises himself as an angel of light." (2 Corinthians 11:14)
See this article on how a researcher of "Close Encounters of the Fourth Kind" unveils the truth about abductions:
https://creation.com/en/articles/lifting-the-veil-ufo-phenomenon