I do not find myself depressed about how little I know of this wonderful world. Rather, I am optimistic.
Should I discover that I indeed will live forever, then I have an eternity of discovery to anticipate. If not I but my species lives forever, then we have an eternity of discovery to anticipate. If neither I nor my species is eternal, then there is still more Universe to know than we have time to discover. However it falls out, there will be no end to new learning. For all the time we have, the Universe is ample. If we are mindful, then we will not be bored.
I first gained this insight from the Old Testament Book of Isaiah, Chapter 6, Verses 1-4:
In the year that King Uzziah died, I saw the Lord, high and exalted, seated on a throne; and the train of his robe filled the temple. Above him were seraphim, each with six wings: With two wings they covered their faces, with two they covered their feet, and with two they were flying. And they were calling to one another:
“Holy, holy, holy is the LORD Almighty;
the whole earth is full of his glory.”
At the sound of their voices the doorposts and thresholds shook and the temple was filled with smoke.
Whether one gives this a religious or a poetic interpretation, it seems clear to me that Isaiah is suggesting that the reality of the Universe is rich, complex, and varied enough to sustain the eternal contemplation of such advanced intellects as seraphim. It will more than sustain the investigation of humanity.
This is indeed very good news.
You have to stop somewhere — the middle seems best.