General Science Notes Chapter 16 Class 6 Maharashtra Board

Notes For All Chapters – General Science Class 6

The Universe

The Universe

• The universe is everything that exists, including stars, planets, and galaxies.
• We can see stars in the sky at night. A telescope helps us see them better.

The Milky Way and Galaxies

• A galaxy is a group of many stars and their planets.
• The Milky Way is our galaxy.
• The nearest galaxy to the Milky Way is Andromeda.
• There are different shapes of galaxies: Spiral, Elliptical, Barred Spiral, and Irregular.

Stars

Stars are big, hot balls of gases that shine.
They come in different colors like blue, white, yellow, and red.
Types of stars:

• Sun-like stars – Similar to our Sun (e.g., Sirius, Alpha Centauri).
• Red Giants – Large and bright but cooler than the Sun.
• Supernova – Bigger and brighter than Red Giants.
• Binary Stars – Two or more stars revolving around each other.
• Variable Stars – Their brightness changes (e.g., Polaris).

The Solar System

• The solar system has the Sun, 8 planets, moons, asteroids, comets, and meteors.
• The Sun is a hot, yellow star in the center.
• The inner planets (Mercury, Venus, Earth, Mars) have hard surfaces.
• The outer planets (Jupiter, Saturn, Uranus, Neptune) are large and have rings.

Other Celestial Bodies

• Moons – Satellites that orbit planets (Earth’s moon takes 27.3 days to orbit Earth).
• Asteroids – Small rocky bodies between Mars and Jupiter.
• Dwarf planets – Small planets like Pluto.
• Comets – Ice and dust objects with long tails (e.g., Halley’s Comet).
• Meteors – Falling stars; if they reach Earth, they are called meteorites.

Planets and Their Features