How exactly do we even know what planets like Saturn or Jupiter even are? I understand Venus and Mars we have been there. But planets outside of those are just big colorful balls of gas that look like nothing else we have observed before? Sure we can look at them with telescopes but we are just assuming they are one thing without any real proof. How do we even know what the Sun is? Seems like space is just a whole bunch of guessing and taking people's word for stuff