Infinite number of planets with life

[Hovik]

When we know something in a scientific sense, there is a lot of good evidence to back it up. Things that we "knew" in the past that have been since changed weren't based on scientific reasoning, and are therefore meaningless. For example, we know that the Earth orbits the sun, and we know that because of a more advanced understanding the cosmos. We're not going to determine in the future that this is incorrect because the fact of the matter is, the Earth does orbit the sun. We know this.

Science adjusts its views based on new evidence from observation.

yeah, in the future the earth is not going to turn up to be a cube... we know that, but we don't know if the universe is infinite, if before there was something, we suppose that there was anything, but no one was there, no one saw the universe from another universe, or found a wall or edge.

However, that isn't to say that we won't one day find out the answers to these questions. That's the beauty of science: it's pretty darn good at finding answers to big questions. Just like we determined the Earth orbits the Sun, we can and will one day determine the rest of the nature. Even now we have very compelling observations and experiments that suggest profound insights into the nature of the universe, and our understanding can only get better.