Crash Course: Big History

Introduction

• Presenter: John Green
• Series will cover the history of everything from the Big Bang to now
• History often considered to start with written records; arbitrary start point
• Big History starts with the creation of the universe and extends to its end

Purpose of Big History

• To provide context to existence
• Integrates multiple fields: cosmology, geology, biology, social sciences, literature, physics
• Focus on broad historical questions
• Uses the ultimate scale; zooms out to see the big picture

Key Concepts

• Earthrise photo (1968) signifies perspective on physical space
• Importance of zooming out to understand history
• Details become fuzzier but provide broader context

Timeline of the Universe (Compressed to 13 years)

• Universe begins (13 years ago)
• First stars and galaxies (12 years ago)
• Earth forms (4.5 years ago)
• First single-celled life (4 years ago)
• Multi-cellular organisms (Cambrian explosion) (3.5 years ago)
• Dinosaurs extinct (3 weeks ago)
• Humans and chimpanzees share ancestor (3 days ago)
• First Homo sapiens (50 minutes ago)
• Agriculture (5 minutes ago)
• Ancient Egypt (3 minutes ago)
• Black Death (24 seconds ago)
• Industrial Revolution (6 seconds ago)
• World War I (2 seconds ago)
• Cold War, man on the moon, birth of the internet (last second)

The Big Bang

• Creation of space-time
• Universe expanded from a tiny point very quickly
• Universe's major work done within first few seconds
• Universe inflated enormously in less than a blink of an eye
• BICEP project supports inflation theory

Formation of Early Universe

• Anti-matter and matter annihilated, leaving one billionth of matter
• Matter from the Big Bang formed everything in the universe
• Atoms formed: mostly hydrogen and helium
• Complex elements formed in stars over billions of years
• Universe cooled down, allowing matter and radiation to separate

Cosmic Background Radiation

• Radiation seen today as Cosmic Background Radiation (CBR)
• CBR is evidence of the Big Bang
• Present everywhere, even in radio static

Expansion of the Universe

• Edwin Hubble's discovery of redshift in galaxies
• Universe expanding; supported by Doppler effect
• Discovery of other galaxies beyond the Milky Way
• Big Bang cosmologists predicted the amount of radiation released
• 1960s discovery of CBR confirmed predictions

Looking Into the Past

• Light speed allows us to see events from 13.8 billion years ago
• Chemical composition of the early universe confirmed
• Helium, hydrogen, and lithium observed

Future Discoveries

• Dark matter unknown but affects gravitational behavior
• Expect future discoveries to alter the story

Conclusion

• Big History connects with every human life
• Forms a common story for mankind
• Next episode will explore more about stars and elements

Key Takeaways

• History cannot be separated from science
• Big History provides a coherent story of the universe
• Enhances understanding and perspective by zooming out