A question explored by BioLogos President Deb Haarsma.
There are 5 subquestions, but let me focus on one: “Would meeting aliens change our understanding of the cross?” (“At the core of Christianity is the death of the incarnate Christ on a Roman cross, bringing redemption for humans. Is redemption unique to Earth?”)
Haarsma identifies 4 theories:
1. Aliens are not fallen, and thus have no need for redemption….
2. Aliens are fallen, and they have their own relationship with God that is different from ours….
3. Aliens are fallen, but included in Christ’s redemptive work on Earth….
4. Aliens are fallen, but Christ’s incarnation and redemptive work are repeated on their own worlds….
The difficulty of all 4 of these options might drive you to avoid the question by choosing one of the 2 other options. The truth of Christianity implies the nonexistence of aliens. Or: If aliens exist, Christianity is not true.