4.6% of the universe is visible to us. The observable universe is regular matter—stars, galaxies and other cosmic things that emit or reflect light. But most of the universe is dark matter (27%) and dark energy (68%). Dark matter doesn’t emit light and interacts weakly with electromagnetic radiation so it’s invisible to us. Dark energy is even more mysterious and its properties are still unknown.
The universe is bigger than what we can see. It’s infinite or at least much bigger than what we can see because of the speed of light and the expansion of space.
So the observable universe, what we can see with our telescopes and instruments, is just a tiny part of the whole universe. The rest is dark matter, dark energy and possibly other regions and phenomena beyond our understanding and detection.
