This isn't correct. You're falling victim to a fallacy sometimes known as privileging the hypothesis. When you look back and say, "Look at all the things people thought were impossible but are now possible!" you're ignoring all things that people thought were impossible and are still impossible. Moreover, you're looking over all the things people thought were possible but are actually impossible.

The entire frame of your questions shows the fallacy because you explicitly abandon all other notions to just come up with things that were thought impossible but are now mundane.

It's true that we don't know everything, but implying that because we don't know everything we know nothing is absolutely ridiculous. All current knowledge of physics points towards entropy, and moreover the second law of thermodynamics, as being one of the most important and consistent laws of physics. It's so important that one of the most well-known physicists in the world is so well-known because he created a theory of black holes that meshes with our existing theory of entropy, proving that the second law still holds. The idea that we should abandon this knowledge because, well, it's inconvenient strikes me as being disingenuous in the highest order.

Anyone can say, "Well, you don't know everything, so you may be wrong." That doesn't make it an informed or useful comment.