Christianity IS Geocentrism.

[Lek]

It's all in Genesis 1:28 which says:

"God blessed them and said to them, "Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground.""

Man is God's greatest creation, even greater than the angels. Why? Because the angels have no choice but to obey God. Man has free will. He has a choice of either obeying or disobeying God, and when he chooses, out of his own free will, to obey God, he is greater than the angels. The Qur'an confirms this in Surat At-Tīn [95:4] which says:

"We have certainly created man in the best of stature;"

The best of molds. And in Surat Al-'A`rāf [7:11]:

"And We have certainly created you, [O Mankind], and given you [human] form. Then We said to the angels, "Prostrate to Adam"; so they prostrated, except for Iblees. He was not of those who prostrated."

Both the Bible and the Qur'an say that man was God's greatest creation. Who says it wasn't? Lek.

It is also mentioned in Ephesians 2:10 as "work of art" or masterpiece. "For we are God’s handiwork, created in Christ Jesus to do good works, which God prepared in advance for us to do."

Yes he created man in his image and to rule over the earth and created him lower than the angels. Psalm 8:4-5
4 what is mankind that you are mindful of them,
human beings that you care for them?[a]
5 You have made them[b] a little lower than the angels[c]
and crowned them[d] with glory and honor.
I don't know about the quran, but the bible never mentions that mankind was the greatest creation in the universe or was to rule over the entire universe.

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Before the discovery that the Earth was indeed a planet, floating in space, it was believed the Earth was the only place you could really "be". It only made sense to say that the Earth is everything in "our world", most likely due to the spread of religion. A God or Gods, in the imperceptible Heavens, looking down upon the Earth. Pretty standard stuff for theism. Then, with the invention and improvement of the telescope, we were able to determine there are other worlds out there, orbiting our sun. Then, we found out that the Sun is just a star, and there are countless other solar systems out there. And then, we learned that all these billions stars form a galaxy. Then, we even learned that that there are as many galaxies in the universe as there are stars in a galaxy!

And throughout all of this discovery, the religious side's reaction was always:

"Okay, so maybe there are other planets, but there aren't other solar systems! Why would God do that?"

"Okay, so maybe there are other solar systems, but there aren't other galaxies! Why would God do that?"

And now we have "Okay, so maybe there are other galaxies, but there aren't other universes! Why would God do that?"

It is clear that these beliefs were created using the knowledge of the time, and that as more and more information comes our way, religious people will need to do more and more mental gymnastics in order to comply with popular science, just as they have done for the last 2000 years.


Moving on to the possibility of more of God's creations throughout the cosmos.

Were they created before or after us? What happens if they sin/fall from grace? Are they damned for all eternity the same as we were? Would/could God deliver his son/another son to their world to pay for their sins, even though the Bible says Jesus was his only son?

Questions like this are why outlandish speculations like these usually have no general consensus amongst Christians.

I really don't need to do any mental gymnastics here. The bible doesn't talk about creatures on others planets or multiple universes. Your question concerning whether or not creatures on other planets would sin and how they would be saved are things to ponder, but that's all we can do. I think that God, who is almighty and omnipotent, can surely figure that out. If we ever run into some aliens, then we can discuss that with them at that time.