Lecture Notes: Advances in Space Technology and Celestial Objects

Introduction

• Recent advances in space technology enable cross-disciplinary collaboration.
  • Fields involved: physics, chemistry, biology, geology.
• Focus: Near-Earth objects such as comets and asteroids.
• Objective: Understanding the origins of the solar system through these studies.

Comets

• Historical Perspective
  • Ancient beliefs linked comets to bad luck and omens of war.
  • Described as heads with long streaming hair or swords.
• Composition and Behavior
  • Made up of rock, dust, and ice.
  • Orbital patterns: huge elliptical orbits.
  • Ice melts near the sun, forming a visible coma and tail.
  • Solar wind forms the tail, which can reach up to 150 million kilometers.
• Origin and Impact Hypothesis
  • Thought to originate from the Oort cloud.
  • A possible hypothesis for the extinction of dinosaurs involves a comet impact.

Meteors

• Definition and Observation
  • Known as falling or shooting stars.
  • Occur when meteoroids enter Earth's atmosphere and burn up.
  • Friction with atmospheric gas causes them to glow and vaporize.
• Coloration of Meteors
  • Determined by chemical composition and speed.
  • Colors include: orange-yellow (sodium), yellow (iron), blue-green (magnesium), violet (calcium), red (nitrogen/oxygen).
• Differences in Terminology
  • Meteoroid: in space, size varies from dust grains to small asteroids.
  • Meteor: a meteoroid that burns up upon entering Earth's atmosphere.
  • Meteorite: a meteor that survives the atmospheric entry and hits the ground.

Interesting Facts About Meteors

• Millions enter Earth's atmosphere daily.
• Visible up to 120 km above the surface.
• Generally, the size of pebbles to baseballs.
• Origin recognition date: 1833.

Asteroids

• Nature and Composition
  • Rocky or metallic objects orbiting the sun.
  • Reflect little light, difficult to observe.
  • Sizes vary from pebbles to mountains.
  • Known as minor planets or planetoids.
  • Ceres: once considered the largest asteroid, now a dwarf planet.
• Orbital Characteristics
  • Many reside in the asteroid belt between Mars and Jupiter.
  • Orbit in elliptical paths, influenced by larger planetary bodies like Jupiter.

Conclusion

• Summary
  • Comets, asteroids, meteors all orbit the sun with distinct characteristics.
  • Comets: made of ice and dust, with nuclei, heads, and tails.
  • Asteroids: rocky, metallic, smaller than planets.
  • Meteors: result from meteoroids entering Earth's atmosphere and burning up.
• Encouragement to keep exploring and learning about celestial phenomena.