LSAT 128 | Section 4 | Reading Comprehension: Q18

RC Question 18 Explanation

QUESTION TEXT: Which one of the following statements about spectroscopy …

DISCUSSION: Spectroscopy is discussed in paragraph 3. We don’t actually know much about the technique itself. What we know is:

• Payne suspected other scientists’ preconceptions about the sun’s composition led to them interpreting spectroscopic data wrong
• Spectroscopic data indicated the sun is 90% hydrogen and the rest mostly helium

___________

1. The passage discussed spectroscopy in the context of astronomy, but it never claims it was exclusive to astronomy.
2. She challenged the skewed interpretation of the data, not the accuracy of the data itself.
3. The passage doesn’t link spectroscopy to the discovery of nuclear fusion.
4. This is wrong. Scientists trusted spectroscopy. But they misinterpreted its data.
5. CORRECT. Paragraph 3 tells us the sun is 90% hydrogen and most of the rest is helium. But scientists believed it was mostly iron, which means spectroscopy was sensitive enough to detect even small amounts of elements like iron and helium (which each constitute less than 10%).