Humans have a hard time contemplating large numbers and objects. And when it comes to really big things like the size of our Sun, our galaxy and the Universe, we simply lose a sense of scale. Sure, we can put a number to these beastly objects, but we can’t really contemplate the actual magnitude of their existence. For example, we know that the Earth’s diameter is ~12500 km. But that doesn’t mean that we can contemplate such a giant ball of matter with all its topology and life forms in one go. That feeling is strictly reserved for the physical and mental senses of an astronaut.