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Difficulty: MediumInferences and Implicit Meaning

When Cecilia Payne published her 1925 doctoral dissertation on stellar atmospheres, her determination that hydrogen was overwhelmingly the most abundant element in stars was met with profound skepticism by the astronomical establishment. At the time, mainstream astrophysics, led by figures such as Henry Norris Russell, operated under the assumption that the elemental composition of stellar atmospheres closely mirrored that of Earth. To account for the disproportionately strong absorption lines of hydrogen observed in stellar spectra without abandoning terrestrial elemental ratios, prevailing models attributed spectral intensity primarily to thermal excitation conditions rather than actual elemental abundance. Payne’s rigorous application of Meghnad Saha’s ionization theory allowed her to decouple line intensity from relative abundance, demonstrating that line strength was a function of both temperature and chemical concentration. Although Russell initially persuaded Payne to frame her conclusion regarding hydrogen abundance as likely spurious, he subsequently published independent calculations confirming her findings. Consequently, while Payne is now recognized for discovering the chemical makeup of stars, contemporary historians argue that the initial resistance to her work stemmed less from institutional bias than from an entrenched theoretical commitment to terrestrial compositional parity.

Which of the following can be inferred from the passage regarding mainstream astrophysics prior to Payne���s 1925 dissertation?

  1. It explained the intensity of stellar hydrogen lines by attributing it to temperature factors rather than elevated chemical concentration.Answer
  2. B
    It utilized Meghnad Saha’s ionization theory to demonstrate that stellar atmospheric composition was identical to Earth's composition.
  3. C
    It rejected the assumption that terrestrial elemental ratios could serve as an accurate baseline for analyzing celestial bodies.
  4. D
    It dismissed Payne’s empirical findings primarily because of pervasive institutional hostility toward women scholars in astronomy.
  5. E
    It established that thermal excitation alone completely determined all observed spectral variations across different stellar types.

Answer

Prior to Payne's dissertation, mainstream astrophysics accounted for strong hydrogen absorption lines by attributing them to thermal excitation conditions rather than high chemical abundance.
The passage explicitly notes that in order to maintain the baseline assumption of terrestrial elemental ratios, early astrophysicists attributed the strong hydrogen lines to thermal excitation rather than actual abundance. Therefore, it can be inferred that they explained these spectral features through temperature mechanisms rather than higher chemical proportions.

Step-by-Step Solution

1
Identify the target of the inference in the passage
The prompt asks for a valid inference regarding the beliefs or methods of 'mainstream astrophysics prior to Payne’s 1925 dissertation'.
Locating the relevant section of text ensures evidence-based reasoning.
2
Analyze passage details regarding pre-1925 astrophysical models
The text states that mainstream astrophysics believed stellar atmospheres mirrored Earth's composition, and to account for strong hydrogen lines without abandoning this ratio, 'prevailing models attributed spectral intensity primarily to thermal excitation conditions rather than actual elemental abundance.'
Implicit meaning must be directly anchored in explicitly stated facts without external assumptions.
3
Match the synthesized passage evidence to the choices
The statement attributing hydrogen line intensity to temperature factors (thermal excitation) rather than high chemical concentration matches the passage evidence directly.
Valid inferences on GRE Reading Comprehension closely paraphrase necessary logical deductions from the text.

Key Concept

Drawing Valid Inferences from Dense Academic Prose
Estimated Time:2m 0s
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Topics

Inferences and Implicit Meaning

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