One of the very few philosophical contemplations I had as a kid was this: If we are to reach the end of the universe, what will we find? Will we find endless void, another "universe" -- or a colossal "frame" of sorts, that prevents us from moving forward in our exploration, simply because there is nothing to explore beyond said "frame"?
Recently, I have reached an interesting conclusion about our knowledge. It is extremely limited, regardless of how "know-it-all" someone might be. That is because there are many things in existence that have yet to be seen, let alone discovered, by anyone.
For example, we have yet to reach the full bottom of this planet's ocean. We can infer that there could be species underwater of which we are not aware, and vice versa. Likewise, topics such as extra-terrestrial life-forms remain a topic of debate, as do other issues such as the possibility of an afterlife, a spiritual layer to reality, and so on.
But the thing is, if there is no "frame" to this, i.e., if there are things in existence that are possible simply due to our great ignorance, then the possibilities for everything are theoretically endless. Infinite. If there is no "wall" or "frame" in this universe that forbids us from knowing more, then the possibility of us knowing more, is infinite. It's limitless, as long as we get to live as long as possible as a species.
There were things in existence that our ancestors believed were impossible or too unrealistic to be implemented, from air travel to submarines to the ability to converse with people instantly. Likewise, there could be things today that some of us consider to be impossible. Except when they are possible, theoretically, in some point in the future. Long-term or otherwise (usually long-term).
Who said there are no aliens that are as smart as we are, no matter how far they exist in the universe? Who said we wouldn't be able to ever teleport from one place to another at our own convenience? Who said A.I. wouldn't need the same rights as we do, simply because they might reach sentience?
In other words, as long as there is no validation of a concrete limitation of possibility, then possibility is endless in theory, regardless of our time and place in the universe. This is why I am confident today, unlike my child-self, that there are no "frames" blocking us from knowing more, should we ever reach the "edge" of the universe, assuming such an edge exists.
The thing that leads to mystery is ignorance. If we were not ignorant, but omniscient, then any form of mystery would be overrated by us. This is why ignorance is "good" if it exists within us, as it can be utilized for further knowledge, or at least, for more wondering. This could lead to the following question: Would humanity ever get rid of its total ignorance of the universe?
We already know much about the parts of it that we have already discovered, such as certain planets having rains of glass and acid (look it up), other planets being similar to Earth in terms of having water, and, possibly, another life form or forms, but as long as there is infinity in the universe, our potential to know the universe, is, in itself, infinite.
The universe isn't a video clip, or so I am inclined to believe. If I am to reach the very end of the universe, no "forcefield" will prevent me from moving forward, beyond "all there is". Who even knows what lies beyond the "end" of the universe?
In conclusion, the possibilities are endless, like existence itself. This is one of the reasons I chose to be agnostic in my beliefs; I do not know if there is divinity, but especially because I don't know. I choose to keep an open mind about it. It's because I admit that I am ignorant regardless of faith. It's on the same scale as sentient aliens.
Do we know for certain if there are other sentient life forms in this universe? We do not know. But because of our ignorance about it, it is our choice to turn it into faith, into denial, or into open-mindedness. The same should apply, I believe, to anything in existence that is not certainly known as the existence of the mundane.