Multiple Choice
Why is it that astronomers will NOT see fluctuations in light output in times shorter than about 1 day when they observe an extragalactic source whose diameter is about 1 light-day?
A) Absorption of light by intergalactic matter will smooth out rapid fluctuations within the beam.
B) The light from different parts of the source will be Doppler-shifted by different amounts, allowing observers to see only an average shift.
C) It is inconceivable that a source of this size could vary on such short time scales.
D) Arrival times will be different from different parts of the source, which will smooth out short-term fluctuations.
Correct Answer:
Verified
Correct Answer:
Verified
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