Actually we can, because we have precise measurements and we can observe something as basic as a line, that's 4th grade math, practically. If you're just going to keep going to something we cannot prove scientifically as undermining science, you're fundamentally missing the point, because science is descriptive, not prescriptive, in its goals
I can understand the universe, I never claimed, nor do any honest scientists, that we can understand it perfectly, because there is pretty much always room for further investigation, which is the beauty of it (see my quote on perfection in signature for slight elaboration). It's not a matter of faith that I can derive understanding of the universe if the understanding is essentially provisional in nature, not something that would require faith, but a general trust in cogency of principles that are neutral in application with proper methodology, unlike the dogmatic doctrinal quibblings in faith and religion
And knowing the universe is not the same as understanding the universe, you're equivocating between 2 terms and thinking that because you change paragraphs I won't notice that detail, not a good sign of critical thought if you rely on people being short-sighted and being convinced by your "argument"