Belief is either something I want to be true, or seems true although I don't have solid evidence. I believe that in the universe there will be many worlds with living beings that eventually evolve to be comparable to humans in mental capacity and the ability to create, but that due to how space time works we will never directly interact with them. They won't be close enough, or our time periods of existence won't match up if either of us attempt interstellar travel. Millions of years is a blink of an eye in the scope of the universe, but it is so vast that the odds are high that another planet will have similar conditions for carbon based life, not to mention other possible forms of life.

Knowledge is supported by evidence. It might not be a perfect explanation or understanding, but it is what is known based on the current information. We now know planets exist around other stars, but before we could observe them it would be a belief to say they existed. The difference is supporting evidence.