[I]n science we have to be particularly cautious about 'why' questions. When we ask, 'Why?' we usually mean 'How?' If we can answer the latter, that … - Lawrence M. Krauss

What's going to happen in the far future? Remember a hundred years ago we thought we lived into static eternal Universe. What will the future bring? The amazing thing is, for civilizations that live in a far future, what will they see? Well, the Universe is accelerating. That means all the distant galaxies are getting carried away from us, and eventually they'll move away from us faster than the speed of light. It's allowed in General relativity. They will disappear. The longer we wait, the less we will see. In a hundred billion years any observers evolving on stars around [us]... and there will be stars just like our Sun in 100 billion years. Any observers and civilizations... evolving around those stars will see nothing except for our Galaxy, which is exactly the picture they had in 1915. All evidence of the Hubble expansion will disappear. Why? Because we won't see other galaxies moving apart from us. So they will have no evidence, in fact, of Big Bang. They won't see the Hubble expansion. They won't even know about dark energy, and I won't go into that. They won't know about the cosmic microwave background - it will disappear too. It will redshift away, and it turns out for fancy reasons: there is a plasma in our Galaxy and when the Universe is 50 times its present age the microwave background won't able to propagate in our Galaxy. All evidence of the Big Bang will have disappeared, and those scientists will discover quantum mechanics, discover relativity, discover evolution, discover all the basic principles of science that we understand today, use the best observations they can do with the best telescopes they will build and they will derive a picture of the Universe which is completely wrong. They will derive a picture of the Universe as being one Galaxy surrounded by empty space that's static and eternal. Falsifiable science will produce the wrong answer. In fact, I want to end with the good news. We live in a very special time, the only time we can observationally verify that we live in a very special time.

Five hundred years of science have liberated humanity from the shackles of enforced ignorance.

There is a maxim about the universe which I always tell my students: That which is not explicitly forbidden is guaranteed to occur.