The Face of Immortality?

Hello there.

    Over the past few days, I have had the pleasure of stopping for a moment to watch the first Alien film and Prometheus. As I did do, I could not escape a single question that continuously nagged at the back of my thoughts: is the Alien a timeless creature? Is it truly immortal? If so, does the Alien represent the lengths to which one would need to alter his or her physiology in order to achieve everlasting life? We all know a certain someone in Prometheus who was very interested in obtaining immortality. I can not help but wonder: if his wish had been granted, would he have been made the host to a facehugger-like organism? Is immortality within the scope of the universe the continuance of one's genetics within the ever-living shell of a nightmarish and utterly inhuman creature? As always, your thoughts and conjecture concerning this topic are greatly appreciated, even if you choose to keep them to yourself. :)