Let's explore this from both a reasonable and scientific perspective.
Currently, the state of our knowledge indicates that energy cannot be created nor destroyed.
http://en.wikipedia.org/wiki/EnergySo what does that speak to a reasonable mind? Well, despite the fact that energy cannot be created, it nonetheless exists. So the big question is:
Q: How could something exist if could never be created?
There is only one possible answer:
A: It always existed, eternally.
Since energy cannot be created nor destroyed, then it is infinite, eternal, and exists forever. It existed before measured time and will continue to exist afterwards. It has no timeline, for it is eternal.
Energy exist all through the universe, so what does that tells us? Well, since we have determined that energy is infinite and eternal, then it knows no boundaries such as a measurable universe. What this tells us is that the universe has no size, and it in itself must be infinite and eternal, otherwise energy could not be infinite and eternal. In other words, if the universe could be measured according to height, width, length, weight, then energy would be restricted and subjected to those dimensions of the universe. But that is not possible because energy is infinite, meaning it cannot be contained by any dimensional forces such as height, width, length, and weight.
In short, what this means is that the universe itself is infinite and eternal. Throughout the universe, energy is constantly being converted to matter, and matter converted back to energy. It is a never-ending cycle of transformation, with new matter constantly being formed out of eternal and infinite energy. This process also knows no dimensional boundaries, and continues forever.
So what does this have to do with alien life existing on other planets? Well, mathematically it demonstrates that it is 100% impossible for life to not exist elsewhere in the universe. Since energy and the universe are infinite and eternal, then the possibly of life existing elsewhere is 100% because the possibility itself is infnite, and cannot be measured or contained.
Mathematically, it is impossible for life to not exist elsewhere in the infinite universe for the simple fact that the possibility itself cannot be restricted to a mere possibility, and therefore must be a fact. In other words, an endless and eternal universe produces an endless and eternal possibility, and since we have evidence that life does exist in the universe (ourselves), then the infinite possibility of life existing elsewhere is far more than a mere probability, but a mathematical fact.
Energy is what creates life, because life is matter, and energy converts to matter. Since energy exists infinitely throughout an infinite universe, then energy is busy creating life all through the universe. It always has, and because of this, life itself is eternal.
Eternal life? On the larger universal scale, yes. And it exists everywhere in the universe.
Topic: Are we the Aliens of the universe?