The speaker discusses the concept of the universe and its observable universe. They explain that everything that exists is part of the universe, and anything outside the observable universe is therefore part of the universe as well. However, the observable universe is a more restricted definition of the universe, as it includes everything that humans can perceive or access in some way.
The speaker then delves into the concept of the universe's expansion, using the analogy of space stretching and moving distant objects away. They explain that galaxies are moving away from us due to this expansion, and that at some point, the speed between us and these galaxies will exceed the speed of light, causing them to move beyond the observable universe.
The speaker also discusses the three possible scenarios for the universe's geometry: closed (like a sphere), open (like a Pringles potato), and flat (like a flat plane). They mention that according to our observable universe, the universe appears flat and its acceleration will reduce over time but never stop completely. This is considered a "Perfect Equilibrium" scenario, which some scientists find lacking in explanation.
The speaker then raises questions about why the observable universe appears flat and suggests that the universe might not be flat, but the observable universe is a very small piece of the entire universe. They conclude that everything outside the observable universe is part of the universe, and the better question would be what exists outside the observable universe.
1. The speaker explains that the universe is a term used to describe everything that exists, making it impossible for anything to exist outside of it [Source: Document(page_content="00:00:15.60: impossible for anything to exist outside the universe everything that exists is by definition part of the universe")].
2. The observable universe is a slightly more restricted definition of the universe, referring to everything that human beings can see in one way or another [Source: Document(page_content="00:00:53.16: the observable universe is a a slightly more restricted definition of the universe because the observable universe is everything that we human beings can see in one way or another")].
3. The speaker mentions that the observable universe is expanding, with galaxies moving away from us due to this expansion [Source: Document(page_content="00:02:16.92: expanding that is most of the galaxies are being moved away from us by the expansion of the universe")].
4. The speaker discusses the future of the universe, stating that if gravity dominates, the expansion will stop and all matter will eventually come together again. If dark energy dominates, the expansion will accelerate, and all galaxies will leave the observable universe. If there is equilibrium, the universe will slow down but never stop expanding [Source: Document(page_content="00:04:31.44: in the observable universe the universe is flat and the acceleration of the universe will reduce its pace but it will never stop for good and that is strange this is a Perfect Equilibrium scenario without a good explanation and scientists don't like such precise things that there is no explanation it seems wrong and this raises the question why the universe is so perfectly flat")].
5. The speaker suggests that the universe may not be flat, and that its flat appearance is due to the observable universe being a very small piece of the entire universe [Source: Document(page_content="00:05:27.00: observable universe appears flat because it is a very, very small piece of the entire universe maybe if we could see beyond the limits of our observable universe we we would see that the universe is a giant pringle potato or perhaps it is a cosmic donut and in this way it determines whether the universe will compress again or whether it will expand forever")].
6. The speaker concludes by stating that there is nothing outside the universe, and that a better question would be what is outside the observable universe [Source: Document(page_content="00:05:55.62: better question would be what is outside the observable universe and the answer is literally the answer about the future of space-time")].