SSC Stenographer 2026 PYQ — Question 17

Solution: The correct answer is Giant impact hypothesis.

Explanation:
☛ The Giant Impact Hypothesis (also known as the Theia Impact or Big Splash) is the most widely accepted scientific theory explaining the formation of the Moon.
☛ According to this theory, approximately 4.5 billion years ago, a Mars-sized celestial body named Theia collided with the early proto-Earth.
☛ The massive energy from the collision ejected a large amount of debris into Earth's orbit, which eventually coalesced under gravity to form the Moon.
☛ This theory successfully explains the Moon's small metallic core, low density, and the strong geochemical similarities between Earth and lunar rocks.

Extra Exam-Relevant Facts:
☛ Fission Theory: Proposed by George Darwin in 1879, which suggested that the Moon separated from a rapidly spinning young Earth.
☛ Capture Theory: Proposed that the Moon was formed elsewhere in the Solar System and was later captured by Earth's gravitational field.
☛ Co-formation Theory: Suggests that the Earth and the Moon formed together side-by-side from the primordial accretion disk at the same time.
☛ The Moon is the only natural satellite of Earth and the fifth-largest natural satellite in the Solar System.

Important One-Liners for Upcoming Exams:
☛ What is the scientific study of the Moon called? → Selenology
☛ What was the name of the Mars-sized body involved in the Moon-forming collision? → Theia
☛ How much time does moonlight take to reach the Earth? → Approximately 1.28 to 1.3 seconds
☛ What fraction of Earth's gravity is present on the Moon's surface? → Approximately 1/6th
☛ Which was the first manned mission to land on the Moon? → Apollo 11 (1969)