"fascinated but also a bit unsettled" "existentially insignificant but strangely exalted" “delightful horror” and a “sort of tranquility tinged with terror.”
from https://erraticus.co/2018/12/04/sublime-experience-kant-scho...
"When I consider the short duration of my life, swallowed up in the eternity before and after, the small space which I fill, or even can see, engulfed in the infinite immensity of spaces whereof I know nothing, and which know nothing of me, I am terrified, and wonder that I am here rather than there, for there is no reason why here rather than there, or now rather than then. Who has set me here? By whose order and design have this place and time been destined for me? The eternal silence of these infinite spaces frightens me."
Wikipedia has articles in different languages on it.
Kids have a lot of fun playing with water when they are around 3-5. Fluid dynamics is complex, and it takes our brains a long time to observe and get an intuition of it. All that observation, experimentation, (subconscious) hypothesis formulation, testing, adjustment, retesting is a rewarding experience.
After we are about 7, we pretty much finish understanding the world around us. Leaves fall from trees, but not straight, sometimes they go this way and that because of the wind -> all this would have produce a sense of wonder in someone who's only 3 years old, but when you are 7 it's just old news. We switch to learning about the human world, via school. Sometimes it's fun, sometimes not, but whatever.
But when you encounter quantum mechanics, or special relativity, or generalized relativity, or any number of topics in Physics, your intuition fails you big time. You need to go through a new learning process, just like when you were 3 years old. And that's a tremendous lot of fun.
Now, here's the sad part: a person like Frank Wilczek probably knows everything about physics. All the ins and outs of all the physical theories out there, quantum field theory, quantum chromodynamics (he's basically one of its inventors), general relativity, you name it. For him the number of times he can experience the euphoria of such an intellectual rebirth dwindles by the day. But who knows, maybe that's what it looks like from our vantage point, maybe the world at the frontiers of knowledge is still full of wonders for Frank.