Title: The Future of Humanity on the Cosmic Calendar

Discussion 2: The Cosmic Calendar
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One thing we will see in later chapters is a general life cycle for the Sun. Astronomers can estimate that since the Sun’s formation, it has brightened by 30% over the past 4.5 billion years. It will continue to get brighter still during the next 4.5 billion years. The temperature of the Earth depends directly on the solar luminosity (brightness), so the Earth will heat up. There are feedback mechanisms that help maintain a more-or-less stable climate on Earth – consider trees and the greenhouse effect. But these naturally occurring processes have their limits.
However, over the next 700 million to 1 billion years, as the Sun changes, the temperature on the Earth is projected to climb to over 200°F – right around the temperature where water evaporates. At this point, liquid water would not be able to form on Earth’s surface and life as we know it cannot exist on the planet.
Your assignment: Speculate about the far future. Where will human beings be in a billion years?
One thing that can help put extinction events like this into a cosmological perspective is the Cosmic Calendar. Mentioned in Chapter 1, this “calendar” takes the entirety of the Universe’s history and condenses it into 1-year on a regular calendar. On a calendar like this, dinosaurs survived about one-week while humans have been around for only a few hours.
A really good explanation of this calendar is also available in the 2014 Cosmos series, hosted by Neil deGrasse Tyson. (This show is a re-creation of the 1980’s Cosmos series with host Carl Sagan.)
Cosmos: A Spacetime Odyssey – Cosmic CalendarLinks to an external site. by carterjrfilmsLinks to an external site. https://www.dailymotion.com/video/x3sjrbk