Conceptual Questions
Question 1: Why is Venus hotter than Mercury?
Question: Mercury is the closest planet to the Sun, yet Venus is the hottest planet in the Solar System. Why?
Answer: Mercury has a very thin atmosphere that cannot hold heat. Venus, however, has a very thick atmosphere made mostly of carbon dioxide. This atmosphere acts like a blanket, trapping the Sun’s heat (Greenhouse Effect), making Venus hotter than Mercury.
Question 2: How can we distinguish a planet from a star in the night sky?
Answer:
- Twinkling: Stars usually twinkle due to the atmosphere, while planets shine with a steady light.
- Movement: Planets change their position relative to the stars over days or weeks (they wander), while stars keep their fixed patterns (constellations).
Question 3: Why do we see phases of the Moon?
Answer: We see different shapes of the Moon (phases) because the Moon does not have its own light; it reflects sunlight. As the Moon revolves around the Earth, we see different portions of its sunlit side.
Solar System Facts Review
Fill in the blanks:
- The path a planet takes around the Sun is called its ________. (Orbit)
- The Indian name for the Milky Way galaxy is ________. (Akasha Ganga)
- ________ are also known as “shooting stars” though they are not stars. (Meteors)
- The planet known as the “Red Planet” is ________. (Mars)
Diagram Practice: Solar System Hierarchy
Can you visualize the order of our cosmic address?
Critical Thinking
Scenario: You are stranded on an island without a compass. It is a clear night. How can you find the North direction?
Solution:
- Look for the Big Dipper constellation (shaped like a large spoon).
- Identify the two “pointer stars” at the outer edge of the spoon’s bowl.
- Trace an imaginary line through them.
- This line points to a moderately bright star, the Pole Star (Polaris).
- Face the Pole Star. You are now facing North.