When light from distant stars passes through Earth's atmosphere, it is scattered by air molecules and particles. Blue light scatters more than red light, which is why stars appear to twinkle and why astronomers prefer building observatories at high altitudes or in space, where there is less atmospheric interference.
It can be inferred from the text that
stars do not actually emit light
red light is invisible to astronomers
clearer astronomical observations can be made where atmospheric effects are minimized
all observatories must be located in space
Correct Answer: C
Choice C is the best answer. Astronomers seek locations with less atmospheric interference.
- Context clues: Astronomers prefer "high altitudes or in space" with "less atmospheric interference."
- Meaning: Less interference means clearer observations.
- Verify: The preference for locations above much of the atmosphere confirms this goal.
💡 Strategy: When professionals choose specific locations for their work, infer what makes those locations better.
Choice A is incorrect because the passage discusses starlight being scattered. Choice B is incorrect because red scatters less and is still visible. Choice D is incorrect because "high altitudes" on Earth also work—space isn't required.