Which is why I asked for clarification on what you mean. You asked "And we know this... how?" in response to me asking what you meant.
That was in response to "I'm not sure entirely what you mean. We know for a fact there's other planets, the sun, etc, and those are all in space." That kind if implies you don't believe in those things at all since you didn't answer the question, but rather challenged my view that we know things like the sun or planets exist.