NWT Isa. 45:18
For this is what Jehovah says, The Creator of the heavens, the true God, The One who formed the earth, its Maker who firmly established it, Who did not create it simply for nothing, but formed it to be inhabited: “I am Jehovah, and there is no one else.
Contemporary English Version
The LORD alone is God! He created the heavens and made a world where people can live, instead of creating an empty desert. The LORD alone is God; there are no others.
Good News Translation
The LORD created the heavens--he is the one who is God! He formed and made the earth--he made it firm and lasting. He did not make it a desolate waste, but a place for people to live. It is he who says, "I am the LORD, and there is no other god.
Smith's Literal Translation
For thus said Jehovah creating the heavens, He the God forming the earth, and he made it; he prepared it, be created it not in vain, he formed it to be dwelt in: I Jehovah and none besides.
New American Bible
For thus says the LORD, The creator of the heavens, who is God, The designer and maker of the earth who established it, Not as an empty waste did he create it, but designing it to be lived in: I am the LORD, and there is no other.
Psalm 115:16
“As for the heavens, they belong to Jehovah, But the earth he has given to the sons of men.” [Not earth plus another planet…yet].
Although God created the earth first, He created the earth for humans not humans for the earth. That shows a purpose in the creation of the planet earth AND especially humans.
What is the purpose of trillions of galaxies and planets in the physical realm of existence well beyond our vision to appreciate? Only humans in the physical realm will be able to eventually achieve immortality and everlasting life. Therefore, we will travel beyond our tiny planet someday. Eternity is a long time. And likely there is life but not intelligent life with free will of choice. The free will of choice to choose to worship the creator must exist on only one planet thus far because of the element of choice and the issue of obedience and disobedience of intelligent creation. The issue must be settled before we can settle other planets, or other intelligent life may be created elsewhere someday.