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Geography

🌍 Chapter 1: The Earth in the Solar System

🔹 Key Concepts

🪐 Celestial Bodies

  • Objects in the night sky like the Sun, Moon, stars are called celestial bodies.

  • Stars are huge, hot glowing balls of gases that emit their own heat and light (e.g. the Sun).

🌌 Constellations

  • A constellation is a group of stars forming a pattern.

  • Ursa Major (Big Bear) and Saptarishi (Seven Sages) are famous constellations.

  • Saptarishi is part of Ursa Major and helps locate the Pole Star.

🌟 Pole Star (North Star)

  • Appears fixed in the northern sky.

  • Used for navigation as it points north.

  • Can be located using the Saptarishi constellation.

🔹 The Solar System

☀️ The Sun

  • A star at the center of the solar system.

  • Source of all heat and light.

  • Nearest star to Earth.

🌍 Planets

  • Do not emit light.

  • Orbit around the Sun.

  • 8 planets:
    🔹 Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

  • Orbit = fixed path around the sun.

🧠 Tip: Use mnemonic – My Very Educated Mother Just Served Us Noodles

🌏 Earth

  • The only planet known to support life.

  • Known as the Blue Planet (2/3rd surface is water).

  • Shape: Geoid (slightly flattened at poles).

🌙 The Moon

  • Natural satellite of Earth.

  • Distance: 3,84,400 km

  • Time for 1 revolution = 27 days.

  • Always shows the same face to Earth.

☄️ Asteroids

  • Rocky objects found between Mars and Jupiter.

  • Orbit the Sun.

🪨 Meteoroids

  • Small rock pieces in space.

  • When entering Earth’s atmosphere, they burn → shooting stars.

🌌 Milky Way Galaxy

  • Galaxy that includes our solar system.

  • Appears as a white band across the sky.

  • Also known as Akash Ganga.

📊 Visual Summary

🌠 Term 🌟 Description
Celestial Body Natural object in space (Sun, stars, planets, moon)
Star Emits own light (e.g., Sun)
Planet Orbits a star, does not emit light
Satellite Orbits a planet (e.g., Moon)
Asteroid Rocky body between Mars & Jupiter
Meteoroid Space rock that may enter Earth’s atmosphere
Constellation Group of stars forming a pattern (e.g., Saptarishi)
Pole Star Appears fixed in the sky, indicates north

❓ Quick Questions (Test Yourself)

  1. Which planet is called Earth’s twin?
    → Venus

  2. Which celestial body appears fixed in the northern sky?
    → Pole Star

  3. What are constellations?
    → Group of stars forming patterns

  4. Why is Earth called the blue planet?
    → Due to large presence of water

  5. Where are asteroids found?
    → Between Mars and Jupiter

📝 Homework

✅ Read this again before bed.
✅ Memorize order of planets.
✅ Try drawing the Solar System diagram.
✅ Practice 5 MCQs.