In this video, I will try to answer the question, what the future of life, earth, and the cosmos may look like. I would like to reflect briefly on why I included videos about the future in a history course. Many of my colleagues and I have noticed that after a journey through big history, students really want to know how the story will continue. I think this curiosity is important, because if you know more about possible futures, you may be able to be better prepared for them. In fact, I think this curiosity is so important that it may be one of the reasons why people study history in the first place. After all, knowing where you came from may help you understand where you are going a bit better. If this is indeed the case, then studying big history may be particularly useful, because it focuses on underlying principles that have help shape the entire known past and are therefore likely to also help shape the future. But before I will tell you a little bit more about principles and their importance for the future, first, a word of caution. The future, obviously, is not just influence by these principles but also by known unknowns, and unknown unknowns. Known unknowns are things we know could happen in the future, such as a comet or asteroid impact. We just don't know if, when, or where they will happen. Unknown unknowns are things that could happen that we're currently unaware of. To give you an example, 100 years ago the developments of MOOCs like this one would probably have been such an unknown unknown. In the rest of the video, I will tell you a bit more about known unknowns, but I obviously cannot tell you anything about unknown unknowns. I can only mention that it might impact the future in ways we currently cannot even imagine yet. So, what known unknowns may influence the future of life and our planet? Some known unknowns are things that happened in the past and might happen again. Examples of such things are volcanic events such as basalt floods that have been associated with a number of mass extinctions in the past. Any eruption of super volcanoes such as a Toba eruption in Indonesia, that may have nearly led to the extinction of our own species, some 70,000 years ago. And I already mentioned, comets or asteroid impacts that have periodically contributed to extinctions, most notably, the extinction of the dinosaurs 65 million years ago. These things might happen again. In fact, we are pretty sure that a basalt flood or supervolcano eruption will happen again, and we even have some candidates, such as, for instance, Yellowstone supervolcano. We just don't know when and where these things will happen. Likewise, we are also pretty sure a giant comet or asteroid will hit the Earth again someday. Even though, we are currently unaware of any that will come dangerously close to us in the foreseeable future. A different type of known unknown is how humans will influence the future of life, Earth, and the universe. For instance, we do not know if our own species will be able to survive the next few centuries. And if it does, how its capacities influence life, our planet and possibly even our cosmic neighborhood will develop. Compared to these known unknowns, we are a bit more certain about how the underlying principles, the underlying patterns that we've been able to discern in big history, may help shape the future. We have seen that in big history, complexity can arise when energy flows through matter within certain Goldilocks conditions. So, we could wonder, what will happen to the matter and energy flows and the Goldilocks conditions required for life, earth, and the cosmos? Most life forms get their energy directly or indirectly from the sun and that star will continue to shine for another 5 billion years. In fact, its luminosity will increase by about 10% every billion years. So in principle, there should be enough energy to sustain life for the next 5 billion years. There's a problem though, the increase in luminosity will lead to a deterioration of the Goldilocks conditions required for life. For instance, it will lead to increase of the withering of rocks. This process will remove carbon dioxide from the atmosphere up to the point where some 900 million years from now, there is too little left to sustain photosynthesis. This will mean the end of plants and algae and eventually also the animals and fungi that eat plant and algae. That is, if the increase in solar luminosity doesn't lead to temperatures lethal for all but the simplest forms of life, first, this may happen from about 1.5 billion years from now. Next, within another billion years, the increasing luminosity of the sun will lead to the evaporation of the oceans. And to a greenhouse effect that will turn the Earth into a very dry and very hot place. On such a planet, life will come to an end, as will the process of plate tectonics, for which water is required. In about 5 billion years from now, the sun's life will also come to an end. This will happen when it will have exhausted all its fuel and it will blow up into a red giant with a diameter of about 250 times its current size. In the process, it may either swallow or scorch the earth and eventually it will blow away its outer shell and will remain as a white dwarf that will slowly cool. While this is happening, our galaxy will be colliding with our galactic neighbor Andromeda, and the collision of gas clouds in these merchant galaxies that may happen from 4 billion years into the future, will trigger the formation of new stars. But eventually these stars will run out of fuel too. And this will happen in about 10 to the power of 14 years, and that's 1 point 14 zeros. After that, there will be no stars left to power the complexity as we know it today. The universe will be dark and empty and it will grow even darker and emptier. This will be the case because scientists now think that the universe will continue to expand forever. It simply doesn't contain enough matter to lead to gravitational effects strong enough to counter the accelerated expansion of the universe. According to most scientists, while the universe becomes emptier, its constituents will slowly fall apart until after about 10 to the power of 100 years, that's a 1 with 100 zeroes. Only electrons, photons, and a couple other small particles will remain. This means that for most of its life, our universe will be a rather boring places. But, when you think about it, it also means that we're currently living in a very special time when dense energy flows through matter, power a great variety of complexity wherever the Goldilocks conditions permit it. So, in a way, we're actually very privileged to be able to witness our universe in what is, in fact, its most exuberant and most creative phase.
