We only understand about 15% of the Universe, and we're probably wrong about much of that. For instance, we know dark matter is pervasive throughout the Universe, and we don't have the slightest idea of what it is.
Also, one of the leading theories of why we haven't met other intelligent alien cultures is because there is one major ancient, highly advanced race that is so devoted to being the only race on the Universe, that every time they find any evidence of another intelligent race, they travel there and extinguish them entirely.
It is already too late to save us. We have been beaming all sorts of electronic signals into the universe in every direction for decades, and sooner or later, it will reach THEM.
