Q. Consider the following scientific observations over geological times:

1. The Moon is moving away from the Earth
2. The Earth is moving closer to the Sun
3. The mean solar day is getting longer
4. The Earth's rotation speed is slowing down

Which of the above statements is/are correct?
Answer: 1, 3 and 4
Notes: Statement 1 is correct: The Moon is slowly moving away from Earth (~3.8 cm/year). Statement 2 is incorrect: Earth's average distance from the Sun remains roughly the same over geological time. Statements 3 and 4 are correct: Tidal friction causes Earth's rotation to slow, making days longer. Thus, only statements 1, 3, and 4 are correct.