Lecture Notes: Understanding Earth and the Universe

Introduction

• Earth and Neighborhood
  • Earth: Our home
  • Solar system: Our cosmic neighborhood

Distance and Scale

• Earth and Moon

  • Distance: Up to 252,088 miles at farthest point
  • All planets in the solar system can fit into this distance

• Planetary Comparisons

  • Great Red Spot on Jupiter: 2x size of Earth
  • Saturn: 9x wider than Earth
  • Saturn’s rings contain fragments as large as mountains

Perspective on Size and Distance

• Sun and Earth

  • Earth from different locations:
    • Moon, Mars, behind Saturn’s rings, beyond Neptune (4 billion miles away)
  • Time perspective:
    • 1 million seconds = 11.5 days
    • 1 billion seconds = 31 years

• Sun Compared to Stars

  • Sun’s size vs. Earth
  • V Y Canis Majoris: 2,000x diameter of the Sun

Galaxies

• Milky Way and Beyond

  • Milky Way size: 100,000 light-years in diameter (621 quadrillion miles)
  • Earth’s position in a small part of the Milky Way
  • NGC 6744: A galaxy twice as wide as the Milky Way

• Universe Scale

  • Hubble telescope image: Thousands of galaxies
  • Galaxies contain millions/billions of stars and planets
  • Age of some objects: Formed 11 billion years ago (3 billion years post-Big Bang)

Conclusion

• Perspective on Life
  • The vastness of the universe offers perspective on daily problems
  • Earth is our home within a vast cosmos