Back to the subject,
I'm in agreement with those saying that the Bible simply doesn't speak to the issue of what else might be out there.
Let's face it, life most certainly, according to the Bible, exists elsewhere besides this earth.
The Bible speaks of the different creatures that are in heaven. Some of them sound pretty weird. There are the seraphim, the cherubim and Revelation 4 speaks of four living creatures.
Since we know that living creatures can inhabit that place known as heaven, then obviously there is life outside of earth.
God's creation is vast... unimaginably huge... that He might have placed life on other planets is very plausible. As for who would be their Redeemer? Jesus is the Redeemer. John tells us that Jesus did many things, so many that the earth itself couldn't contain the books. As others have said, perhaps the beings on other planets haven't sinned... we have no way of knowing any of this, but it is just as speculative to say that there isn't life on other planets as it is to say there is...
That said, I reject the notion that aliens have been visiting our planet.