Natural Satellites and Other Objects

📚 Key Concepts

🔹 The Moon

The Moon is Earth’s natural satellite. It revolves around Earth in about 27 days.

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Key Features:

  • About 1/4 the size of Earth in diameter
  • Distance from Earth: About 384,000 km
  • Has craters formed by asteroid impacts
  • No atmosphere, water, or life
  • Shows different phases as it revolves around Earth

India’s Moon Missions:

  • Chandrayaan-1 (2008): First mission
  • Chandrayaan-2 (2019): Second mission
  • Chandrayaan-3 (2023): Successfully landed near Moon’s south pole
  • National Space Day: August 23 (marking Chandrayaan-3 success)

🔹 Other Objects in Solar System

1. Asteroids

  • Small, rocky, irregular-shaped objects
  • Most found in asteroid belt between Mars and Jupiter
  • Sizes range from 10 m to about 500 km
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2. Comets

  • Made of dust, gases, rocks, and ice
  • Develop long tails when approaching the Sun
  • Called Dhūmaketu in Sanskrit
  • Halley’s Comet appears every 76 years (last seen in 1986)
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