MCQ Detailed View

Both Titan, the largest moon of Saturn, and Triton, the largest moon of Neptune, have atmospheres composed mainly of nitrogen (N₂). This is unusual among moons in the solar system, as most moons lack significant atmospheres due to their small size and weak gravity. Titan and Triton are exceptions because of their larger mass and colder surface temperatures, which allow them to retain gases.

Titan’s atmosphere is dense and nitrogen-rich, accounting for about 95% nitrogen and small amounts of methane (CH₄) and other hydrocarbons. This methane undergoes photochemical reactions in sunlight, forming complex organic compounds that create Titan’s orange haze. Titan’s atmosphere is thicker than Earth’s, with surface pressure about 1.5 times that of Earth’s atmosphere.

Triton’s atmosphere is much thinner but still mainly nitrogen, with traces of methane. The nitrogen on Triton exists in a cycle similar to Pluto, where it can freeze onto the surface during colder seasons and sublimate back into the atmosphere when warmed by sunlight. Seasonal changes and geyser-like activity on Triton’s surface release nitrogen gas, maintaining its thin atmosphere.

The other options in the question are incorrect. Titan is not associated with Jupiter or Uranus, and their atmospheres are not dominated by hydrogen like gas giants. Mars and Venus have carbon dioxide-rich atmospheres, not hydrogen. The correct shared feature of Titan and Triton is their nitrogen-dominated atmospheres.

This fact is significant in planetary science because nitrogen is also the main component of Earth’s atmosphere. The study of Titan and Triton helps scientists understand atmospheric evolution, cryovolcanism, and potential chemical processes that may resemble early Earth conditions.

Therefore, the atmospheres of Titan (Saturn’s moon) and Triton (Neptune’s moon) are mainly composed of nitrogen.