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Question
While we know of thousands of quasars, it is likely none of them still exist today; explain.Answer
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B) Their energy appears to be non-stellar synchrotron radiation.
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Why aren't there young stars in the halo?
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What advantage do radio astronomers have over optical ones in mapping the entire Milky Way?
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How did Herschel try to map our Galaxy 200 years ago, and why did he fail?
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