Gaining knowledge comes hand-in-hand with knowing your own ignorance. When you think about it, when gaining knowledge about a topic, space for example, the more you know what you don't know, or can't know. Therefore, the more insight you gain in the topic, the more you become aware of your own ignorance, and thus feel less knowledgeable about said topic.
In contrast to those that are less knowledgeable, they don't know what they don't know about the topic, therefore don't feel like they know nothing. If i were to use an analogy to expand on this, I think the most appropriate would be a jigsaw puzzle. The more pieces you can fit together, the more aware you become of the gaps within the jigsaw. Therefore you are aware of your own ignorance. If one never attempts the jigsaw, they don't have enough pieces to know that there are pieces missing, therefore are less knowledgeable of their own ignorance.
I'm not sure if irony is the correct term to use here, but I believe it to be an interesting concept to think that some of the greatest thinkers the world has known, probably feel/felt more ignorant about the world and the universe than the average person. Like I suggested earlier, the more knowledge we gain, the more knowledge we know we don't know. Thanks for reading, I hope this made sense and is worthy of your time.